# Meal scheduling corrects obesogenic diet induced-uncoupling of cortico-hippocampal activities supporting memory

Prabahan Chakraborty, Yann Dromard, Emilie M André, Maheva Dedin, Margarita Arango-Lievano, Ana Raner, Antoine Besnard, Thamyris Santos Silva, Jean-Christophe Helbling, Guillaume Ferreira, et al.

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## ► To cite this version:

Prabahan Chakraborty, Yann Dromard, Emilie M André, Maheva Dedin, Margarita Arango-Lievano, et al.. Meal scheduling corrects obesogenic diet induced-uncoupling of cortico-hippocampal activities supporting memory. EBioMedicine, 2025, 117, pp.105783. 10.1016/j.ebiom.2025.105783. hal-05122786

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# Meal scheduling corrects obesogenic diet induced-uncoupling of cortico-hippocampal activities supporting memory

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Prabahan Chakraborty,ª,ᵇ Yann Dromard,ª Emilie M. André,ª,ᶜ Maheva Dedin,ª Margarita Arango-Lievano,ª Ana Raner,ᵈ Antoine Besnard,ª Thamyris Santos Silva,ª Jean-Christophe Helbling,ᵈ Guillaume Ferreira,ᵈ Etienne Challet,ᶜ Marie-Pierre Moisan,ᵈ,**, and Freddy Jeanneteauª,\*

oa

OPEN ACCESS

ªInstitut de Génomique Fonctionnelle, University of Montpellier, INSERM, CNRS, 141 rue de la Cardonille, 34094, Montpellier, France

ᵇDepartment of Genetic Engineering, School of Bioengineering, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, 60203, India

ᶜDépartement de Maieutique, University of Montpellier, 641 Avenue du Doyen Gaston Giraud, 34070, France

ᵈUniv. Bordeaux, INRAE, INP Bordeaux, Nutrition et Neurobiologie intégrée, NutriNeurO, 146 Rue Léo Saignat, 33076, Bordeaux, France

ᵉInstitut des Neuroscience Cellulaires et intégratives, University of Strasbourg, CNRS, 8 All. du Général Rouvillois, 67000, Strasbourg, France

## Summary

**Background** Highly caloric food consumed around the clock perturbs the metabolism and cognitive functioning. We hypothesised that obesogenic food could alter neuronal representations of memory depending on the feeding-fasting cycle.

**Methods** We tracked memory performance, dendritic spine dynamics and neuronal representations of memory in C57Bl6J mice fed obesogenic food *ad libitum* from peri-adolescence. We aimed to correct energy rich diet-induced plasticity deficits and cognitive impairment with time-restricted feeding in males and females. We further used chemogenetics, pharmacology and knock-in mice to investigate functional correlates underlying diet-induced neurocognitive impairments.

**Findings** We found that changes in the feeding-fasting cycle reverted the effects of *ad libitum* obesogenic food on memory impairment in both sexes (n = 55, *p* = 0.003). Concurrently, it also corrected the increased dendritic spine maintenance and neuroactivity in hippocampus and the decreased spine maintenance and activity in parietal cortex (n = 48, *p* < 0.005). Bi-directional effects in cortex and hippocampus mediated by glucocorticoid signalling are causal to behavioural changes (n = 91, *p* = 0.0008), and scaling hippocampal with cortical activities restored memory in mice fed obesogenic food (n = 44, *p* = 0.02).

**Interpretation** These results indicate that meal scheduling is a promising approach to confront glucocorticoid signalling bias and memory deficits caused by obesogenic food.

**Funding** Agence Nationale de la Recherche (ANR-21-CE14-0086), Fondation pour la Recherche sur le Cerveau (FRC).

**Copyright** © 2025 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

**Keywords:** Obesity; Adolescence; Intermittent fasting; Memory; Connectivity; Engram

## Introduction

Fighting the obesity epidemic is a top priority of health practitioners, given that its prevalence has tripled in the last decade. Direct causes include over-nutrition with energy-dense food, reduced physical activity, and lifestyle pattern changes,¹ making it important to identify and correct mechanistic components underlying this global epidemic.

One principal factor that drives such physiological maladaptation is the misalignment of endogenous biological rhythms, which synchronises activity-sleep and

feeding-fasting to the appropriate time of the day-night cycle.² Repeated disruption of such patterns due to mismatched timing of eating and sleeping increases the risk of obesity and comorbidities like mental illnesses.³ This may arise due to extended periods of indoor artificial lighting causing shorter sleep and longer access to food, particularly Western-style diet (high caloric diet enriched in saturated fat and refined sugars), that can disrupt circadian rhythms at the behavioural, molecular and metabolic levels.⁴

eBioMedicine
2025;117: 105783

Published Online xxx
https://doi.org/10.1016/j.ebiom.2025.105783

<footnote>*Corresponding author.</footnote>

<footnote>**Corresponding author.</footnote>

<footnote>E-mail addresses: freddy.jeanneteau@igf.cnrs.fr (F. Jeanneteau), marie-pierre.moisan@inrae.fr (M.-P. Moisan).</footnote>
Research in context

Evidence before this study

What and when we eat contributes to our health. This is particularly worrisome for children and adolescents because of the lifelong effects that unrestricted snacking on highly caloric food could cause on brain maturation. A variety of school policies and nutritional programs have emerged to prevent poor nutritional habits. But obesity is on the rise and a major cause of neurological disabilities difficult to detect and treat. Human studies are limited by the size and duration of sampling with low resolution metrics to prove causality between nutritional habits and cognitive health trajectory. Animal studies have shown that all-day snacking on highly caloric food disrupts innate biological rhythms that influence hormonal secretions, neuronal structure and function in brain regions that encode, store and retrieve memories. It is not known if, like adipocytes and hepatocytes, the brain in obesity can develop glucocorticoid resistance -a state that would prevent the robust but complex effects of this hormone on memory- to the point that researchers still question whether glucocorticoids are a cause or solution to obesity related-brain comorbidities.

Added value of this study

Longitudinal sampling of several metrics at multiple
timepoints in mice fed highly caloric food since peri-
adolescence up to adulthood showed that the trajectory of
obesity-related brain comorbidities is corrected when
reinstating the feeding/fasting cycle, albeit consuming highly
caloric food. Glucocorticoid resistance manifesting as receptor
phosphorylation deficits impeding coincidence detection

between glucocorticoid and neuronal activities -was reversible when reinstating the feeding/fasting cycle, albeit consuming highly caloric food. Studies in receptor mutant mice lacking a phosphorylation site-independent of glucocorticoids showed it is required to reinstate neuroplasticity to changes of feeding/fasting cycle, albeit consuming highly caloric food. Fos-trapping experiments showed less engagement of pyramidal neurons in the cortex when activity-dependent phosphorylation of glucocorticoid receptor was low, and more in the hippocampus of mice fed obesogenic diet, which reinstating the feeding/fasting cycle reverted, albeit consuming highly caloric food. Finally, chemogenetic experiments confirmed the requirement for the co-engagement of cortical and hippocampal pyramidal neurons to fully remember, despite poor nutritional habits.

Implications of all the available evidence

The cortico-hippocampal activities necessary for remembering are uncoupled by obesogenic food consumed *ad libitum* but not on meal scheduling, extending neuroimaging correlation studies in adolescents with obesity. Poor nutritional habits cause glucocorticoid resistance in the brain as previously suggested, with altered neuronal representation of memory that meal scheduling corrected. The findings should be validated in humans to inform school policy and health advice. Future research will develop allosteric ligands targeting phosphorylation motifs in the glucocorticoid receptor as more specific alternative to orthosteric ligands for the treatment of obesity-related brain comorbidities.

Circadian glucocorticoid rhythm, for instance, is
disrupted by high-fat diet (HFD) in mice,⁵ hand-in-hand
with a change in feeding rhythms.⁶ Reducing glucocor-
ticoid levels by treatment with a glucocorticoid
synthesis-inhibitor, improves recognition memory in
HFD-fed mice.⁷ Other studies reported dysregulation of
hippocampal glucocorticoid-receptor (GR) levels rather
than its ligand concentration in a model of obesity-
related memory deficits.⁸ Although glucocorticoids use
GR to propagate rapid non-genomic and slow genomic
signalling, the impairment of long-term synaptic
potentiation from induction when fed HFD suggests
that rapid signalling is involved, and possibly via GR
phosphorylation as it correlates with its reversal.⁹
Among the multiple GR phosphorylation sites, serine
134 (S134)-mediated signalling triggers brain-derived
neurotrophic factor (BDNF)-dependent positive neuro-
plasticity of glucocorticoids, learning and memory¹⁰
whereas S226-mediated signalling triggers negative
plasticity of glucocorticoids and cognitive impairment.¹¹
The ratio of phosphorylation between S134 and S226
reflects the direction of neuroplasticity and memory
performance¹² that could explain bidirectional effects of

glucocorticoids in obesity.¹² Importantly, the human
polymorphism Val66Met in *BDNF* gene disrupts
activity-dependent secretion of BDNF, S134-mediated
neuroplasticity¹³ and glucocorticoid sensitivity.¹⁴
Consistently, double transgenic mice carrying the
*BDNF* Val66Met genotype and a loss-of-function muta-
tion in S134 impaired activity-dependent neuroplasticity
of memory without additive effects, confirming that
both pathways interact and that the sole glucocorticoid-
dependent sites are insufficient to transduce the full
spectrum of GR signalling.¹³ Therefore, coincidence
detection of BDNF and glucocorticoids converging on
GR-dependent kinases and phosphatases determines
the spectrum of signalling responses.¹⁵ Given that GR
activation impairs neuroplasticity by suppressing BDNF
expression in obese mice,¹⁶ we reasoned that HFD could
alter the GR phosphorylation ratio that supports struc-
tural changes from the glucocorticoid-binding pocket to
the docking of signalling effectors.¹⁷,¹⁸ In agreement, low
phosphorylation at S134 while high at S226 in the cortex
of patients with Alzheimer's disease correlated with
memory impairment.¹² Furthermore, substitution of
S134 by an alanine residue while retaining S226 in the
APP/PS1 mouse model of Alzheimer's disease accelerated the progression of cortical amyloidosis and synaptic damage.¹² While interventions like environmental enrichment reverted GR-signalling defects in obese mice⁸ unlike in *BDNF* Val66Met mice,¹³ whether GR-phosphorylation ratio underlies memory impairment by HFD remains unknown, and could offer a more specific approach to correcting deficits.

To correct obesity-related diseases, a range of nutritional programs emerged, including caloric restriction (e.g. low-fat food), nutrient choice (e.g. ketogenic diet) and intermittent fasting (e.g. time-restricted feeding, TRF). For instance, most participants with mild cognitive impairment practicing intermittent fasting reverted to the neurotypical ageing category, which was more than in participants not abiding to the practice.¹⁹,²⁰ However, human studies are limited by the acute nature of cognitive testing, the mix of different age-groups and the scarcity of long-term follow-ups investigating the effects of a variety of intermittent fasting styles on cognitive functioning.²¹ Animal models, by contrast, provide a robust system to investigate long-term effects of intermittent fasting designs on cognition. Beneficial effects of TRF were reported on memory and hippocampal synaptic plasticity in adult rodents fed with normal-diet or HFD²² known to impair cognition in different age-groups,²³,²⁴ diet duration,²⁵ neurodegeneration models²⁶ and ageing-related conditions.²⁷,²⁸ Given that memory retrieval is functionally linked to the maintenance and reactivation of collective synapses between task-allocated neurons,²⁹ we ask whether HFD disrupts such mechanisms by altering glucocorticoids signalling, and if TRF can reverse them.

We addressed these questions using longitudinal *in vivo* imaging of dendritic spines in two brain regions involved in recognition memory—the hippocampus and sensory cortex, that are both involved in early and remote memory retrieval.¹⁰ This allowed us to track neuroplastic changes of (i) memory-impairment with peri-adolescent obesogenic diet, (ii) its correction in the *same animal* with TRF in adulthood, and (iii) in mouse carriers of the loss-of-function mutation S134A while retaining S226-mediated signalling. We found that the GR-phosphorylation ratio sustained the bi-directional neuroplasticity between cortex and hippocampus by obesogenic-diet. We additionally used chemogenetics and RU486 infusion to determine the functional role of bi-directional neuroplasticity.

## Methods

### Ethics

Experiments abide to the Directive by the Council of European Communities (86/609/EEC) and were approved by the French Ministry of research and ethics committee (CCEA-APAFIS1769-28536, 1574-18707). All efforts were made to minimise animal suffering and

reduce their number. All experiments adhere to the ARRIVE guidelines.

### Animals

Age/weight/sex-matched B6.Cg-Tg(*Thy1-YFP*)Hjrs/J, *Fostm2.1(acre/ERT2)*Luo/J, B6.Cg-Gt (ROSA) 26Sortm14(CAG-tdTomato)Hze/J from Jackson labs, and NR3C1 knock-in mutant Ser134Ala/Ser267Ala (*B6.Tg(Nr3c1tm2/Jean*)/J)¹³ were group-housed under standard pathogen-free laboratory conditions (12/12 light/dark cycle, lights on at 7 am, 22 °C, 60% humidity, food and water *ad libitum*). See Table 1 for details. All lines were maintained for more than 10 generations in C57BL6J background. All animals were bred and raised in the IGF experimental husbandry EOPS zone. Genotypes were determined before group allocation at P21. We used males and females from P21 to 4.5 months of age. GR phosphorylation numbering scheme by species is described elsewhere.³¹ All chemogenetic experiments are done in a mix of males and females as no sex difference were identified in the primary analysis (Figs. 1 and 2), and *in vivo* imaging was only done in males (due to excessive fluorescence in *Thy1-YFP* female mice). Mice are observed everyday by zootechnicians. Grid of endpoint measures includes body weight, behaviour, posture, dehydration. All animals were handled by experimenters for a week before testing. All animals were habituated to the experiment-room for 1 h before behaviour tests. For surgeries, all animals were administered pre-op with lidocaine, anaesthetics and myorelaxant and post-op with meloxicam, carprofen.

### Ad libitum high fat and sucrose diet (HFD) and time-restricted feeding (TRF)

Mice were fed since weaning (day 21) to either a high fat-high sucrose diet (HF: 4.7 kcal/g, cholesterol 0.195 mg/g (45% kcal saturated fat), 35% carbohydrates with 50% sucrose, D12451 Research Diet) or a control normal chow (NC: 3.3 kcal/g, 8% kcal fat, 45% proteins, 73% carbohydrates, A04 SAFE) for 12 weeks, provided either *ad libitum* or with time-restriction (food access from zt11 to zt1, active period) for the last 4 weeks, an adaption from published protocols.³²,³³ This regimen was chosen over shorter TRF durations (2 weeks,³⁴) that has been reported in adult mice treated with HFD for 18 weeks, but not adolescent mice as in this study. Here, the effects of 4-weeks TRF examined in young adults superimpose with the *ad libitum* consumption of HF or NC during peri-adolescence. Mice fed *ad libitum* on NC or subjected to TRF were given the same normal chow diet all along. Similarly, mice fed *ad libitum* on HFD or subjected to TRF received the same high-fat/sugar meal. Food intake was monitored automatically using MBRose HM-2 system (Faaborg, Denmark) according to the supplier recommendations. Briefly, male mice were kept 6 per cage and individual monitoring of food intake
Antibodies

<table><thead><tr><th>Immunogen</th><th>Details</th><th>Source</th><th>Use</th><th>Manufacturer</th></tr></thead><tbody><tr><td>GFP</td><td>Cat# ab13970, RRID:AB_300798</td><td>Chicken polyclonal</td><td>1:3000</td><td>Abcam (validated in Arango-Lievano et al. Scientific reports 2016)</td></tr><tr><td>RFP</td><td>Cat# 600-401-379, RRID:AB_2209751</td><td>Rabbit polyclonal</td><td>1:3000</td><td>Rockland (validated in Arango-Lievano et al. Scientific reports 2016)</td></tr><tr><td>Iba1</td><td>Cat# 5076 RRID:AB_2224402</td><td>Rabbit polyclonal</td><td>1:1000</td><td>Abcam (validated in Dromard et al. Acta Neuropathologica com 2022)</td></tr><tr><td>GFAP</td><td>Cat# 7260, RRID:AB_305808</td><td>Rabbit polyclonal</td><td>1:1000</td><td>Merck (validated in Dromard et al. Acta Neuropathologica com 2022)</td></tr><tr><td>c-Fos (9F6)</td><td>Cat# 2250, RRID:AB_2247211</td><td>Rabbit polyclonal</td><td>1:1000</td><td>Cell Signalling Technology (validated in Borie et al. Cell report Medicine 2024)</td></tr><tr><td>c-Fos (E8)</td><td>Cat# sc-166940, RRID:AB_10609634</td><td>Mouse monoclonal</td><td>1:100</td><td>Santa Cruz Laboratories (validated in Borie et al. Cell report Medicine 2024)</td></tr><tr><td>GAD67</td><td>Cat# MAB5406, RRID:AB_2278725</td><td>Mouse monoclonal</td><td>1:500</td><td>Merck (validated in Arango-Lievano et al. PNAS 2019)</td></tr><tr><td>p-GR [S267]</td><td>S267 in human, S284 in mice, S287 in rat</td><td>Rabitt polyclonal</td><td>1:1000</td><td>Custom made (Lambert et al. MCB., 2013, Arango-Lievano et al. PNAS 2019, Dromard et al. Acta Neuropathol Com 2022)</td></tr><tr><td>p-GR [S134]</td><td>S134 in human, S152 in mice, S155 in rat</td><td>Rabbit polyclonal</td><td>1:1000</td><td>Custom made (Lambert et al. MCB., 2013, Arango-Lievano et al. PNAS 2019, Dromard et al. Acta Neuropathol Com 2022)</td></tr><tr><td>p-GR [S211]</td><td>S211 in human, S232 in rat</td><td>Rabbit polyclonal</td><td>1:1000</td><td>Gift from M. Garabedian NYU USA (validated in Arango-Lievano et al. PNAS 2015, Lambert et al. MCB., 2013)</td></tr><tr><td>p-GR [S226]</td><td>S226 in human, S246 in rat</td><td>Rabbit polyclonal</td><td>1:1000</td><td>Gift from M. Garabedian NYU USA (validated in Arango-Lievano et al. PNAS 2015, Lambert et al. MCB., 2013)</td></tr><tr><td>Goat anti-rabbit Alexa-Fluor488/594/647</td><td>Cat#A-11034/11037/21244; RRID: AB_2576217, RRID: AB_2534095, RRID: AB_2535812</td><td></td><td>1:2000</td><td>Thermo Fisher Scientific</td></tr><tr><td>Goat anti-mouse Alexa-Fluor488/594/647</td><td>Cat#A-11029/11032/21236; RRID: AB_2534088; RRID: AB_2534091; RRID: AB_141725</td><td></td><td>1:2000</td><td>Thermo Fisher Scientific</td></tr></tbody></table>

Drugs

<table><thead><tr><th></th><th>Effect</th><th>Working concentration</th><th>Comments</th><th>Manufacturer</th></tr></thead><tbody><tr><td colspan="5"><strong>Compound name</strong></td></tr><tr><td>CNO</td><td>DREADD ligand CAS# 2250025-93-3 HB6149</td><td>In vivo: 2 mg/kg soluble in 0.9% saline with 0.5% DMSO</td><td>Used in intraperitoneal injections</td><td>Hello Bio</td></tr><tr><td>RU486</td><td>GR antagonist CHEBI:50692</td><td>In vivo: 10 mg/kg soluble in 2% ethanol in 0.9% saline</td><td>Used in intraperitoneal injections</td><td>Hello Bio</td></tr><tr><td>4OH-TAM</td><td>ERa agonist CAS# 68047-06-3 HB2508</td><td>In vivo: 25 mg/kg in 15% DMF and 85% sesame oil</td><td>Used in intraperitoneal injections</td><td>Hello Bio</td></tr><tr><td colspan="5"><strong>Other compounds</strong></td></tr><tr><td>High fat food irradiated</td><td>D12451i</td><td>45% Kcal from fat</td><td>4.7 kcal/g [consisting of 24% lipids (45 kcal) saturated, 35% refined sugar (35 kcal) of which 50% sucrose</td><td>Research diet</td></tr><tr><td>Normal chow food irradiated</td><td>A04</td><td>10% Kcal from fat</td><td>3.3 kcal/g [consisting of 8.4 kcal from fat, 45% proteins and 73% carbohydrates)</td><td>SAFE</td></tr><tr><td>Paraformaldehyde</td><td>Cat#P6148</td><td>4%</td><td>Tissue fixation</td><td>Merck</td></tr><tr><td>pentobarbital</td><td>Anaesthetic VetCode QN51AA01</td><td>In vivo: 50 mg/kg</td><td>Intraperitoneal injection</td><td>Ceva Santé Animale</td></tr><tr><td>xylazine</td><td>anaesthetic VetCode QN05CM92</td><td>In vivo: 1.3 g/kg</td><td>Use in combination with ketamine. Intraperitoneal injection</td><td>Ceva Santé Animale</td></tr><tr><td>Ketamine</td><td>anaesthetic VetCode QN01AX03</td><td>In vivo: 6.6 g/kg</td><td>Use in combination with xylazine. Intraperitoneal injection</td><td>Ceva Santé Animale</td></tr></tbody></table>

Virus

<table><thead><tr><th>Virus name</th><th>Concentration</th><th>Volume injected</th><th>Manufacturer</th></tr></thead><tbody><tr><td>psSAAV-2-mCamk2a-hM3D (Gq)_mCherry-WPRE-hGHp(A)</td><td>14 x 10E12 vg/ml</td><td>500 nL/hemisphere at 2 x 10<sup>11</sup> viruses/mL</td><td>Univ Zurich</td></tr><tr><td>pSSAAV-2-mCamk2a-hM4D (Gi)_mCherry-WPRE-hGHp(A)</td><td>3.1 x 10E12 vg/ml</td><td>500 nL/hemisphere at 2 x 10<sup>11</sup> viruses/mL</td><td>Univ Zurich</td></tr></tbody></table>

Reagents

<table><thead><tr><th>Name</th><th>Catalogue number</th><th>Manufacturer</th></tr></thead><tbody><tr><td>Fluoromount</td><td>CAT# 00-4958-02</td><td>ThermoFisher Scientific</td></tr><tr><td>Dental cement</td><td>CAT#203097</td><td>Paladur, Henry Schein</td></tr></tbody></table>

Mice

<table><thead><tr><th>Name</th><th>Background</th><th>Details</th><th>Source</th></tr></thead><tbody><tr><td>Fostm2.1 (icre/ERT2)Luo/J</td><td>Fos2A-iCreER (TRAP2)</td><td>C57BL6J<br/>Cat#030323;<br/>RRID:IMSR_JAX:030323</td><td>Jackson laboratories</td></tr></tbody></table>

(Table 1 continues on next page)
Mice

<table><thead><tr><th>Name</th><th>Background</th><th>Details</th><th>Source</th></tr></thead><tbody><tr><td colspan="4">(Continued from previous page)</td></tr><tr><td>B6.Cg-Gt (ROSA)26Sor<sup>tm14 (CAG-tdTomato)Hze/J</sup></td><td>Ai14</td><td>C57BL6J</td><td>Cat# 0079144; RRID:IMSR_JAX:007914; Jackson laboratories</td></tr><tr><td>B6.Cg-Tg (Thy1-YFP)HJs/J</td><td>Thy1-YFP-H</td><td>C57BL6J</td><td>Cat#003782; RRID:IMSR_JAX:003782; Jackson laboratories</td></tr><tr><td>B6.Tg(Nr3c1<sup>tm2/jean</sup>)/J</td><td>NR3C1 knockin mutant Ser134Ala/Ser267Ala</td><td>C57BL6J</td><td>Homemade (Arango-Lievano et al. PNAS 2019, Dromard et al. Acta Neuropathol com 2022)</td></tr><tr><td>C57BL6J</td><td></td><td>C57BL6J</td><td>Cat#000664; RRID: IMSR_JAX:000664; Charles River</td></tr></tbody></table>

Genotyping Primers

<table><thead><tr><th>Gene</th><th>Sequence 5'-3'</th></tr></thead><tbody><tr><td>WT F oIMR9020 (Ai14)</td><td>AAG GGA GCT GCA GTG GAG TA</td></tr><tr><td>WT R oIMR9021 (Ai14)</td><td>CCG AAA ATC TGT GGG AAG TC</td></tr><tr><td>Mutant F WPRE oIMR9103 (Ai14)</td><td>GGC ATT AAA GCA GCG TAT CC</td></tr><tr><td>Mutant F tdTomato oIMR9105 (Ai14)</td><td>CTG TTC CTG TAC GGC ATG G</td></tr><tr><td>WT F 37830 (fostrap2)</td><td>GTC CGG TTC CTT CTA TGC AG</td></tr><tr><td>Common 37831 (fostrap2)</td><td>GAA CCT TCG AGG GAA GAC G</td></tr><tr><td>Mutant F 37832 (fostrap2)</td><td>CCT TGC AAA AGT ATT ACA TCA CG</td></tr><tr><td>Primer_01 F NR3C1 knockin mutant Ser134Ala/Ser267Ala</td><td>GCAGGCCGCTCAAGTGTTTTCT</td></tr><tr><td>primer_02 R NR3C1 knockin mutant Ser134Ala/Ser267Ala</td><td>CACTGACCAACGAGAAACGATTAC</td></tr><tr><td>primer_03 F NR3C1 knockin mutant Ser134Ala/Ser267Ala</td><td>GCAGGCAGAAGTGTGTTTAGC</td></tr><tr><td>primer_04 R NR3C1 knockin mutant Ser134Ala/Ser267Ala</td><td>CAGTCATAGCCGAATAGCCTCTC</td></tr><tr><td>Tg R 15731 (Thy1-YFP)</td><td>CGG TGG TGC AGA TGA ACT T</td></tr><tr><td>Tg R 16072 (Thy1-YFP)</td><td>ACA GAC ACA CAC CCA GGA CA</td></tr><tr><td>Control F oIMR7338 (Thy1-YFP)</td><td>CTA GGC CAC AGA ATT GAA AGA TCT</td></tr><tr><td>Control R oIMR7339 (Thy1-YFP)</td><td>GTA GGT GGA AAT TCT AGC ATC ATC C</td></tr></tbody></table>

Softwares and agorithms

<table><thead><tr><th>Name</th><th>Source</th></tr></thead><tbody><tr><td>Graphpad prism 9.0 SCR_002798</td><td>http://graphpad.com</td></tr><tr><td>Adobe Creative Suite 6 (Photoshop, Illustrator)</td><td>https://www.adobe.com/de/products/cs6.html</td></tr><tr><td>Fiji Image J SCR_003070</td><td>http://imagej.net/Fiji</td></tr><tr><td>Behavioural Observation Research Interactive Software (BORIS) v. 7.9.4</td><td>https://boris.readthedocs.io/</td></tr><tr><td>R</td><td>https://www.r-project.org/</td></tr></tbody></table>

Data availability

<table><caption>Table 1: List of reagents.</caption><thead><tr><th>Name</th><th>Source</th></tr></thead><tbody><tr><td>Zenodo</td><td>https://zenodo.org/records/10953723</td></tr></tbody></table>

was ensured by a RFID chip placed under the skin of the neck. Mice of each experimental group were monitored for 6 days during the same period (week 11 and 12 of diet exposure). The last 4 days were kept to calculate mean total calorie intake, diurnal food intake percentage and circadian food intake. For the latter, data were fitted to cosinor regressions (SigmaPlot v13, Systat software Inc., San Jose, CA, USA) as follows: [y = A+(B·cos(2·π·(x-C)/24))] where A is the mean level, B the amplitude, C the acrophase of the 24-h rhythm.

Open field

Mice (males and females) positioned in the centre freely explored an arena (50 × 50 cm, dim light ~50 lux) for 10 min. Animals were continuously recorded on video

for offline scoring of locomotor activity by an observer blind for experimental groups. Total distance travelled and time spent in the centre (29 × 29 cm) were determined with EzTrack (available on Github¹⁵). Data are presented in Fig. 1.

Novel object recognition

Mice (males and females) positioned in the centre freely explored a L-shaped arena (30 × 10 cm, dim light ~50 lux) for 10 min on day 1 for habituation, with identical objects on each side on day 2, and with one old/previously explored (Lego blocks) and one novel object (falcon tube) on each side on day 3. Animals were continuously recorded on video for offline scoring of object exploration by an observer blind to experimental groups. In
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<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

**Fig. 1:** No effect of diet nor schedule on locomotion, anxiety and body weight. **a.** Developmental gain of body weight in males and females as a function of diet change (between week 1 and 8) and schedule change (between week 8 and 12). Bold lines indicate means ± SEM, thin lines individual subjects of n = 6 males +6 females with NC ad libitum, 7 males +7 females with HFS ad libitum, 6 males +4 females with NC restricted, 7 males +4 females with HFS restricted. Data has normal distribution (Shapiro-Wilk test *p* = 0.52). The use of the chi-square distribution instead of the F-distribution is justified by the lack of homoscedasticity (Levene's test *p* < 0.0001). Four-way ANOVA (model type III): Chisq analysis: Effect of diet χ2(1,35) = 0.9 *p* = 0.3, sex χ2(1,35) = 1.2 *p* = 0.2, TRF χ2(1,35) = 0.07 *p* = 0.7, time χ2(1,35) = 292 *p* < 0.0001, diet x sex χ2(1,35) = 0.7 *p* = 0.3, sex x TRF χ2(1,35) = 0.0001 *p* = 0.99, diet x TRF χ2(1,35) = 0.02 *p* = 0.8, sex x time χ2(2,70) = 10 *p* = 0.005, diet x time χ2(2,70) = 14 *p* = 0.0008, TRF x time χ2(2,70) = 0.3 *p* = 0.8, sex x diet x TRF χ2(1,35) = 0.02 *p* = 0.8, sex x diet x time χ2(2,70) = 0.5 *p* = 0.7, sex x time x TRF χ2(2,70) = 3.5 *p* = 0.1, diet x TRF x time χ2(2,70) = 0.01 *p* = 0.9, sex x diet x TRF x time χ2(2,70) = 0.3 *p* = 0.8. Pairwise comparisons with post-hoc Tukey's test indicate no effect of sex within groups at each time points. There is no effect of single factors except time, which interacts with sex and diet. **b.** Distance travelled in the open field in males and females as a function of diet change (between week 1 and 8) and schedule change (between week 8 and 12). Bold lines indicate means ± SEM, thin lines individual subjects of n = 6 males +6 females with NC ad libitum, 7 males +7 females with HFS ad libitum, 6 males +9 females with NC restricted, 6 males +7 females with HFS restricted. Data has normal distribution (Shapiro-Wilk test *p* = 0.06) and homoscedasticity (Levene's test *p* = 0.13). Four-way ANOVA (model type III): Chisq analysis: Effect of sex χ2(1,56) = 1.5 *p* = 0.2, diet χ2(1,56) = 0.9 *p* = 0.3, TRF χ2(1,56) = 0.006 *p* = 0.9, time χ2(1,56) = 4.5 *p* = 0.1, diet x sex χ2(1,56) = 0.5 *p* = 0.4, sex x TRF χ2(1,56) = 0.6 *p* = 0.4, diet x TRF χ2(1,56) = 0.5 *p* = 0.4, sex x time χ2(2,71) = 1.4 *p* = 0.4, diet x time χ2(2,71) = 0.6 *p* = 0.7, TRF x time χ2(2,71) = 2.7 *p* = 0.2, sex x diet x TRF χ2(1,56) = 0.7 *p* = 0.4, sex x diet x time χ2(2,71) = 1.3 *p* = 0.5, sex x time x TRF χ2(2,71) = 1.5 *p* = 0.4, diet x TRF x time χ2(2,71) = 0.02 *p* = 0.9, sex x diet x TRF x time χ2(2,71) = 0.6 *p* = 0.7. There is no effect of single factors nor interactions between factors. **c.** % time spent in the centre of the open field in males and females as a function of diet change (between week 1 and 8) and schedule change
Fig. 3, we reported % time of object exploration as New/ (New + Old) and Old/(New + Old). In Fig. 2, there was too many groups to compare (2 sexes, 3 time points, 2 diets, 2 feeding schedules). Therefore, we opted for the reporting of an object preference index calculated as (New-Old)/(New + Old). For the chemogenetic experiments (Fig. 3), the ligand CNO (clozapine-N-Oxide) 2 mg/kg dissolved in 0.5% DMSO in saline (used a vehicle control) was injected intra-peritoneally 45 min before the retrieval test on day 3. For the pharmacology experiments (Fig. 4), RU486 10 mg/kg dissolved in 2% ethanol in saline (used a vehicle control) was injected IP after the same objects exploration session to disrupt memory consolidation.

## Contextual fear conditioning

This task was always done at the end because it is aversive and could influence the other behavioural metrics if done earlier. A week before testing, mice (males and females) were habituated to the experimenter. One day before conditioning, mice were left to explore without any stimulation for 3 min the neutral context B: rectangular opaque box without grid on the floor (18 × 35 × 22 cm) cleaned with 1% acetic acid lights OFF. This pre-exposure allowed the mice to acclimate and become familiar with the chamber (neutral context) used for the tone re-exposure test. On the next day, mice were placed in context A: transparent Plexiglas chamber (20 × 20 × 30 cm) with an electric grid floor, cleaned with 70% ethanol, lights ON and conditioned with 2 electrical foot-shocks (unconditional stimulus: US 0.4 mA, 1s) and 2 tones (conditional stimulus CS 65 dB, 1000 Hz, 15s) given pseudo-randomly after and before the shocks. More precisely, during the unpairing procedure, 100s after being placed in the chamber animals received a shock, then, after a 20s interval, a tone; finally, after a 30s delay, the same tone and the same shock spaced by a 30s interval were presented. After 20s, animals were returned to their home cage. As the tone is never followed by shock delivery, animals identify the conditioning context (set of static background contextual cues that constitutes the environment in which the conditioning takes place), and not the tone, as the right predictor of the shock (predictive context condition). On day 2, mice were re-exposed to the tone (65 dB 2 min) in context B. More precisely, first 2 min (no tone), next 2 min (tone), and last 2 min (no tone). Conditioned response to the tone is expressed by the percentage of

freezing during the tone presentation. 2 h later mice were re-exposed to the conditioning context A for 6 min without any stimulation (no tone, no shock). Freezing to the context was calculated as the percentage of the total time spent freezing during the successive three blocks of 2 min periods of the test. Freezing, defined as a lack of all movement except respiration, was used as an index of conditioned fear response. Animals were continuously recorded on video for offline second-by-second scoring of freezing by an observer blind to experimental groups.

## Thinned skull cortical window

Thy1-YFP mice anesthetised with ketamine (0.075 mg/ g) and xylazine (0.01 mg/g) were kept warm at 37 °C, with pre-surgical lidocaine (10 mg, drops) on skull, and ophthalmic ointment applied on the eyes. Skull bone was thinned to transparency using disposable ophthalmic surgical blades (Surgistar, Vista, CA, USA) and a disposable head plate implanted over the window for imaging as previously.³⁶ The scalp is sutured and topped with antibiotic cream to avoid infection between imaging sessions.

## Intra-hippocampal optical window

Thy1-YFP mice anesthetised with ketamine (0.075 mg/ g) and xylazine (0.01 mg/g) were kept warm at 37 °C, with pre-surgical lidocaine (10 mg, drops) on skull, and ophthalmic ointment applied on the eyes. A 3-4 mm craniotomy (AP -2.3 mm, ML 2 mm) was prepared by drilling with permanent flow of cold HEPES-buffered artificial cerebrospinal fluid (aCSF in mM, 120 NaCl, 3.5 KCl, 0.4 KH₂PO₄, 15 glucose, 1.2 CaCl₂, 5 NaHCO₃, 1.2 Na₂SO₄, 20 HEPES, pH = 7.4) and removal of dura and cortex by vacuum suction down to callosal projections.³⁷ A detailed map of the pial vasculature and dendritic territories were taken for subsequent relocation as previously described.³⁸ The glass plug was glued to the skull and fixed with the custom head plate with dental cement. Adhesive plastic was kept over the window was protected from dust until imaging. Post-operative care consisted of 1 mg/kg meloxicam administration for 3 days.

## 2-photon image acquisition

Images were acquired in the somatosensory cortex S1 with a FVMPE RS two-photon microscope (Olympus, Hamburg, Germany) equipped with a 20×, numerical

<footnote>(between week 8 and 12). Bold lines indicate means ± SEM, thin lines individual subjects of n = 6 males +6 females with NC ad libitum, 4 males +7 females with HFS ad libitum, 6 males +9 females with NC restricted, 7 males +9 females with HFS restricted. Data has homogeneity of variance (Levene's test p = 0.1). The use of the chi-square distribution instead of the F-distribution is justified by the lack of normality (Shapiro-Wilk test p < 0.0001). Four-way ANOVA (model type III): Chisq analysis: Effect of sex χ²(1,42) = 0.2 p = 0.6, diet χ²(1,42) = 0.1 p = 0.7, TRF χ²(1,42) = 0.01 p = 0.9, time χ²(2,72) = 0.1 p = 0.9, diet x sex χ²(1,42) = 0.4 p = 0.5, sex x TRF χ²(1,42) = 0.01 p = 0.8, diet x TRF χ²(1,42) = 0.01 p = 0.89, sex x time χ²(2,72) = 1.6 p = 0.4, diet x time χ²(2,72) = 1.1 p = 0.5, TRF x time χ²(2,72) = 0.3 p = 0.8, sex x diet x TRF χ²(1,42) = 0.03 p = 0.8, sex x diet x time χ²(2,72) = 2.3 p = 0.3, sex x time x TRF χ²(2,72) = 0.4 p = 0.7, diet x TRF x time χ²(2,72) = 0.6 p = 0.7, sex x diet x TRF x time χ²(2,72) = 0.1 p = 0.5. There is no effect of single factors nor interactions between factors.</footnote>
<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /></figure>

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /></figure>

<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

<figure><img src="image_14.png" /></figure>

**Fig. 2:** *Time-restricted feeding on HFD reverted memory impairments.*

**a.** Males (n = 23) and females (n = 32) fed high fat/sugar (HF) or normal chow (NC) were subjected to repeat testing in the open field (OF), for novel object recognition memory (NOR) and fear conditioning memory (FC). Black colour: *ad libitum*, pink colour: time restricted feeding.

**b.** Diurnal food intake. Means ± SEM, n = 11 mice/group. Unpaired t-test *p* = 0.02.

**c.** Total daily calorie intake. Means ± SEM, n = 12 mice/group. Mann-Whitney test: NC ad lib vs. HF ad lib *p* = 0.002, NC TRF vs. HF TRF *p* = 0.0002, NC ad lib vs. NC TRF *p* = 0.6, HF ad lib vs. HF TRF *p* = 0.18.

**d.** Four days circadian food intake. Non-linear fit, n = 12 mice/group. Amplitude: effect of diet *p* = 0.004, regimen *p* < 0.0001; Mesor: effect of diet *p* = 0.04, regimen *p* = 0.2; Acrophase: effect of diet *p* = 0.9, regimen *p* = 0.19.

**e.** Recall of object recognition memory was assessed 24 h after learning session with the same objects.

**f.** Discrimination of the new object over the old one (index = new/(new + old)). Mice fed NC or HF *ad libitum* (black) or on *restricted-time* (purple). Bold lines indicate means ± SEM, thin lines individual subjects (n = 14 mice with NC *ad libitum*, 11 with HF *ad libitum*, 15 with NC *restricted*, 15 with HF *restricted*).

Four-way ANOVA: Effect of sex × diet × schedule × objects *F*(2,92) = 0.8 *p* = 0.4. Consolidated 3-way ANOVA without sex factor: Effect of diet × schedule × objects *F*(2,151) = 6.08 *p* = 0.002, effect of schedule × objects *F*(2,151) = 5 *p* = 0.007, effect of diet × objects *F*(2,151) = 17.8 *p* < 0.0001, effect of diet × schedule *F*(1,151) = 1.62 *p* = 0.02, effect of diet *F*(1,151) = 48.4 *p* < 0.0001, effect of objects *F*(2,151) = 9.1 *p* = 0.0002, effect of schedule *F*(1,151) = 4.49 *p* = 0.03. See Supplementary Table S1 for post-hoc analysis \* *p* < 0.05 and Cohen's *d* effect size.

**g.** Males (n = 17) and females (n = 31) fed HF or NC were tested for FC memory in adulthood. Electrical foot shocks were delivered during conditioning in context A, while an unpaired tone was delivered in a novel context B. Recall of FC memory was assessed 24 h later in context B with the unpaired tone and 2 h later in the conditioning context A without shocks.

**h.** % Freezing behaviour during recall of the context A. Mice fed NC or HF *ad libitum* (black) on *restricted-time* (purple). Bold lines indicate means ± SEM, thin lines individual subjects (n = 10 mice with NC *ad libitum*, 10 with HF *ad libitum*).
aperture NA1.0 water-immersion objective (Apocromat,
Carl Zeiss) and an InSight ×3 femtosecond-pulsed
infrared laser (Spectra-Physics, Evry, France) for
optimal fluorescence excitation and emission separa-
tion. Laser power was adjusted with the depth from
15 mW superficially and kept below 30 mW. For hip-
pocampal imaging, the cover glass was rinsed with
water and filled with ASCF. Images were acquired in
dCA1 with the same microscope equipped with a long-
range working distance (4 mm) objective 25x NA1.05
water-immersion (XLPLN25XWMP2, Olympus). Exci-
tation was 960 nm for YFP. Images in S1 were taken
with a digital zoom of 7.2x at each image session using
0.75 µm step with a scanning dwell time of 2.55 µsec per
pixel. Images in dCA1 were taken with a digital zoom of
7.2x at each image session using 1 µm step with a
scanning dwell time of 2.55 µsec per pixel. Laser power
was adjusted with the depth from 20 mW superficially
up to 60 mW. Each scan stacks consists of images at
512 × 512 pixels resolution.

Image post-processing and analysis

The field of view (200 × 200 × 150 µm) in consecutive
images was realigned with RegStack plugin and dis-
tances between nearest spines along dendrites
measured with ImageJ. Dendritic spines were marked
manually with the Cell counter plugin of ImageJ. Two or
more additions (or eliminations) of spines ≤5 µm along
a dendrite define a dynamic cluster of formation (or
elimination) as previously described.¹⁷ All clear headed-
protrusions emanating laterally from the dendritic shaft
were counted. In cortex, approximately 200 dendritic
spines from at least 10–20 apical dendritic segments
were counted per conditions throughout the imaging
sessions and averaged per animal. We counted twice
that amount in hippocampus given the higher spine
density at apical dendrites. The presence, loss and gain
of spines were counted between sessions for each
segment and plotted as a function of distance to the
nearest spine. Distance measurement between spines
was set at the base of the neck to the base of the next
spine following the trace of the dendritic shaft. The
proportion of clustered formation (or elimination)
equals the number of spines in clusters divided by the
total number of new spines added (or eliminated) be-
tween imaging sessions. We used a bootstrapping
method to ensure that spine clusters are not random as
previously.¹⁶ New spine survival was defined as the
number of spines gained between image 1 and 2, and
further maintained in image 3, normalised by the

number of spines present in the first time point. Old
spine survival corresponds to the maintenance of pre-
existing spines across time points divided by the total
number of spines at the first time point.

Stereotaxic surgery

AAV2-mCamk2a-hM3D (Gq)\_mCherry-WPRE-hGHp(A),
AAV2-mCamk2a-hM4D (Gi)\_mCherry-WPRE-hGHp(A)
(500 nl, Univ Zurich, Switzerland) were used in this study.
Eleven weeks-old C57BL6J mice were injected at 2 sites in
S1 (AP −0.1 mm and −0.9 mm, ML ± 2.5 mm,
DV −1.0 mm) and/or at one site in dCA1 (AP −1.8 mm,
ML ± 1.5 mm, DV −1.3 mm). Multi-sites expression of
transgenes was verified post-mortem.

Genetic tagging of cells

Transgenic mice with *Fos* promoter that drives the expression of c-Fos and ER<sup>T2</sup>-iCre knocked-in the gene's 3'-UTR<sup>19</sup> were used. Hydroxytamoxifen (4OH-TAM: I.P. 25 mg/kg dissolved in 15% Dimethyl-formamide, 85% sesame oil) sends ER<sup>T2</sup>-iCre into the nucleus expressing tdTomato via loxP recombination.

Histology

Brains were harvested following transcardial perfusion
with phosphate buffered saline (PBS) followed with 4%
paraformaldehyde, and post-fixed for 24 h at 4 °C. Free-
floating coronal sections of 40 µm obtained with a
vibratome, were rinsed in PBS then blocked in 5%
normal goat (or donkey) serum, PBS, 0.1% Triton X-100
for 2 h at 25 °C. Primary antibodies, RFP (1:3000,
Rockland), Iba1 (1:1000, Abcam), GFAP (1:1000,
Merck), c-Fos 9F6 (1:1000, Cell signalling), p-GR S134
(1:1000, homemade¹⁰) p-GR S226 (1:1000, Gift from M.
Garabedian, NYU USA¹⁸), GR P20 (1:400, Santa Cruz
biotechnologies) were incubated for 2 days at 4 °C and
secondary antibodies (1:2000, ThermoFisher Scientific)
for 2 h at 25 °C. Sections were washed in PBS, 0.1%
Triton and mounted in Fluoromount (Sigma Aldrich).
Images were acquired with an epifluorescence micro-
scope (Imager Z1, Carl Zeiss), and the overlap between
c-Fos and YFP cells or c-Fos and tdTomato cells counted
with FIJI by an experimentalist blind to the groups.

Statistics

Animal were randomly allocated to experimental groups
and analysed by scientists blinded to the groups. There
was no a priori calculation of sample size because the
number of mice with correct genotype was never exact.
No data was excluded. Missing timepoints is due to

<footnote>*libitum*, 13 with NC *restricted*, 12 with HF *restricted*). Chisq analysis: Effect of sex χ²*(1,40)* = 0.15 *p* = 0.69, diet χ²*(1,40)* = 6.5 *p* = 0.01, schedule χ²*(1,40)* = 3.7 *p* = 0.05, time χ²*(2,40)* = 72 *p* < 0.0001, diet x schedule χ²*(1,40)* = 5 *p* = 0.02, time x schedule χ²*(2,80)* = 4.8 *p* = 0.09, diet x time χ²*(2,80)* = 1.4 *p* = 0.4, diet x schedule x time χ²*(2,80)* = 0.4 *p* = 0.7, sex x diet χ²*(1,40)* = 0.03 *p* = 0.8, sex x schedule χ²*(1,40)* = 0.2 *p* = 0.6, sex x time χ²*(2,80)* = 1.1 *p* = 0.5, sex x diet x schedule χ²*(1,40)* = 0.2 *p* = 0.6, sex x schedule x time χ²*(2,80)* = 0.4 *p* = 0.7, sex x diet x time χ²*(2,80)* = 2 *p* = 0.3, sex x diet x schedule x time χ²*(2,80)* = 0.4 *p* = 0.4. See Supplementary Table S1 for post-hoc analysis *p* < 0.05 and effect size.</footnote>
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<figure><img src="image_16.png" /></figure>

<figure><img src="image_17.png" /></figure>

<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /></figure>

<figure><img src="image_20.png" /></figure>

<figure><img src="image_21.png" /></figure>

**Fig. 3: Time-restricted feeding on HFD reverted dendritic spine impairments.** a. Design with imaging at 3 time points in *Thy1-YFP* males (n = 24) fed with high fat/sugar (HF) or normal chow (NC). Black colour: *ad libitum*, pink colour: time restricted feeding. b. Longitudinal *in vivo* multi-photon imaging of pyramidal neurons in somatosensory cortex S1 via a transcranial window and in dorsal hippocampus subfield dCA1 via an intrahippocampal window implanted on week 4. Arrows point to dynamic spines. Scale = 4 µm. c. Representation of stable (small black dots) and dynamic (red dots for gains, blue dots for losses) spines along dendritic territories between week 8 and 12. Dynamic remodelling comes in clusters defined as 2 or more dendritic spines within 5 µm distance from each other. d. % Spine addition between week 8 and 12 (means ± SEM of n = 6 mice/group). Two-way ANOVA For S1: Effect of schedule $F_{(1,20)}$ = 12.3 *p* = 0.002, diet $F_{(1,20)}$ = 5.2 *p* = 0.03, interaction $F_{(1,20)}$ = 6.1 *p* = 0.02. For CA1: Effect of schedule $F_{(1,20)}$ = 59 *p* < 0.0001, diet $F_{(1,20)}$ = 35 *p* < 0.0001, interaction $F_{(1,20)}$ = 71 *p* < 0.0001. See Supplementary Table S1 for post-hoc analysis **\*\*p* < 0.01, ***\*\*p* < 0.001 and effect size. e. % Spine elimination between week 8 and 12 (means ± SEM of n = 6 mice/group). Two-way ANOVA For S1: Effect of schedule $F_{(1,20)}$ = 52 *p* < 0.0001, diet $F_{(1,20)}$ = 95 *p* < 0.0001, interaction $F_{(1,20)}$ = 32 *p* < 0.0001. For CA1: Effect of schedule $F_{(1,20)}$ = 11 *p* = 0.003, diet $F_{(1,20)}$ = 0.8 *p* = 0.3, interaction $F_{(1,20)}$ = 3.9 *p* = 0.06. See Supplementary Table S1 for post-hoc analysis \*\*\*\*p* < 0.05, **\*\*\*\*p* < 0.001 and effect size. f. % Old spine maintenance between week 8 and 12 (means ± SEM of n = 6 mice/group). Two-way ANOVA For S1: Effect of schedule $F_{(1,20)}$ = 8 *p* < 0.0001, diet $F_{(1,20)}$ = 57 *p* < 0.0001, interaction $F_{(1,20)}$ = 0.3 *p* = 0.5. For CA1: Effect of schedule $F_{(1,20)}$ = 12 *p* = 0.001, diet $F_{(1,20)}$ = 0.5 *p* = 0.4, interaction $F_{(1,20)}$ = 4.5 *p* = 0.04. See Supplementary Table S1 for post-hoc analysis \*\*\*\*p* < 0.05, **\*\*\*\*p* < 0.01, ***\*\*\*\*p* < 0.001 and effect size. g. % New spine maintenance between week 8 and 13 (means ± SEM of n = 6 mice/group). Two-way ANOVA For S1: Effect of schedule $F_{(1,20)}$ = 10 *p* = 0.003, diet $F_{(1,20)}$ = 9 *p* = 0.006, interaction $F_{(1,20)}$ = 8 *p* = 0.008. For CA1: Effect of schedule $F_{(1,20)}$ = 0.05 *p* = 0.8, diet $F_{(1,20)}$ = 8 *p* = 0.008, interaction $F_{(1,20)}$ = 2.4 *p* = 0.13. See Supplementary Table S1 for post-hoc analysis \*\*\*\*p* < 0.05, **\*\*\*\*p* < 0.01, ***\*\*\*\*p* < 0.001 and effect size.
<figure><img src="image_22.png" /></figure>

**Fig. 4:** Time-restricted feeding on HFD reverted neuronal engagement deficits. a. c-Fos induction labelled with antibodies in pyramidal neurons of somatosensory cortex S1 and dorsal hippocampus subfield dCA1 in *Thy1-YFP* males (n = 28). Arrowheads point to dual labelled cells. HF: high fat/sugar, NC: normal chow. Black colour: ad libitum, pink colour: time restricted feeding. Scale = 50 µm. b. % Fos-activated YFP neurons 1 h after NOR on week 13 (means ± SEM of n = 7 mice/group). Two-way ANOVA for S1: Effect of schedule F(1,24) = 4.7 p = 0.04, diet F(1,24) = 0.6 p = 0.4, interaction F(1,24) = 12 p = 0.001. Two-way ANOVA for CA1 (n = 7 mice/group except n = 6 HF *restricted*): Effect of schedule F(1,23) = 1 p = 0.3, diet F(1,23) = 6.7 p = 0.01, interaction F(1,23) = 2.7 p = 0.1. See *Supplementary Table S1* for post-hoc analysis \*\*p < 0.01 and effect size. c. % YFP neurons among Fos-activated cells 1 h after NOR on week 13 (means ± SEM of n = 7 mice/group). Two-way ANOVA for S1: Effect of schedule F(1,24) = 1.4 p = 0.2, diet F(1,24) = 1.7 p = 0.1, interaction F(1,24) = 0.006 p = 0.9. Two-way ANOVA for CA1 (n = 7 mice/group except n = 6 HF *restricted*): Effect of schedule F(1,23) = 4.4 p = 0.04, diet F(1,23) = 4.6 p = 0.04, interaction F(1,23) = 9.7 p = 0.005 post-hoc analysis \*\*p < 0.01. See *Supplementary Table S1* for post-hoc statistics and effect size. d. Timeline for the genetic tagging in *Fos-TRAP2;Ai14* males (n = 33) of Fos-activated neurons (tdTomato) engaged by novel object recognition (NOR) testing on week 8 and reactivated (cFos induction) on week 13. e. NOR-evoked Fos-induction on week 13 in neurons of S1 and dCA1 engaged by NOR (tagged with tdTomato) on week 8. Arrowheads point to dual labelled cells. Scale = 50 µm. f. % Fos-activated tdTomato cells 1 h after NOR on week 13 (means ± SEM). Two-way
unexpected death from repeated anaesthesia or lack of testing. Normality of datasets was tested with Shapiro-Wilk test and homogeneity of variance with Spearman's or Levene's test. ANOVA was used for multifactorial comparisons with post-hoc analyses reporting significant difference of the means (2-way model: main effects of diet and schedule or DREADD and CNO, 3-way model: main effects of time, diet and schedule or DREADD Gi, Gq and CNO, or genotype, diet and regimen or RU486, vehicle and diet, and their interactions with Prism 9 (GraphPad). We used R for 4-way ANOVA model that included the sex factor and 5-way model that included sex with all other factors in the mutant experiment. The use of the chi-square distribution instead of the F-distribution is justified by the lack of homoscedasticity. For data that did not meet the assumption of parametric analysis, we used the Friedman's test to determine difference between all factors and repeated measures with post-hoc Wilcoxon's test and Kruskal-Wallis test for pairwise comparisons. *p* values were corrected for false discovery rate (α = 0.05), and Cohen's *d* calculated as an indicator of effect size between groups (see Supplemental Table S1 for details).

## Role of funders

Funders had no role in study design, data collection, analyses, interpretation, and writing.

## Results

### Time-restricted feeding on HFD ameliorated memory impairments

To explore the impact of TRF on HFD (45% kcal from fat, 17% sucrose) *ad libitum* since weaning, access to food was limited to zt11-to-zt1 (active period) for postnatal week 12–15, while NC-fed controls too stayed either in TRF schedule or *ad libitum*. Several outcome measures were collected at weaning (baseline, week 1), while on HFD before TRF (week 8), and after 4 weeks of TRF (week 12) (Fig. 2a). After 8 weeks of HFD, males and females had significant change in body weight (*p* = 0.0008, ANOVA Fig. 1a), normal locomotor activity (Fig. 1b), no anxiety (Fig. 1c), and were thus randomly assigned to the *ad libitum* or TRF groups. Diurnal food intake increased in mice fed HFD compared to normal chow (NC) (Fig. 2b). On average over four days, TRF had no impact on calorie intake in mice fed HFD compared to NC (Fig. 2c) but it restored circadian food intake of mice fed HFD back to the normal rhythm of mice fed NC *ad libitum* (Fig. 2c). At weeks 1, 8 and 12, memory

performance was assessed with the novel object recognition (NOR) test (Fig. 2e). Both males and females went from normal performance at weaning (week 1) to cognitive impairment when fed HFD *ad libitum* for 8 and 12 weeks (Fig. 2f). ANOVA with post-hoc comparisons showed significant difference between group-means (*p* < 0.0001) with large effect size (*d* > 2) for HFD compared to NC, with no sex-difference (Supplementary Table S1). Remarkably, TRF on HFD reversed memory impairments in both males (*p* = 0.02) and females (*p* = 0.04) with large effect sizes (male: *d* = 1.78, female: *d* = 1.9), and TRF on NC had no effect on memory-performance (males: *p* = 0.9, *d* = 0.7, females: *p* = 0.9, *d* = 0.6).

We further validated this finding by testing contextual fear memory in the same mice on week 13 (Fig. 2g), as previous studies suggested diet-effects on emotional memory.⁴⁰ In agreement, *ad libitum* HFD reduced the time of freezing in the conditioning context A as compared to NC-fed mice, without sex-differences (Fig. 2e, Supplementary Table S1). ANOVA revealed significant difference between groups (*p* = 0.0002) with large effect size (*d* = 1.35) specific to shock-paired context A, but not to shock-unpaired tone presentation in context B (*p* = 0.9, *d* = 0.4). TRF on HFD also reverted emotional memory impairments across sex (males: *p* = 0.05, *d* = 1.5, females *p* = 0.002, *d* = 1.7), with no effect on NC-fed animals (males: *p* = 0.5, *d* = 0.5, females: *p* = 0.5, *d* = 0.2). Therefore, *ad libitum* HFD degraded both aversive and non-aversive memories, which could be successfully reverted by TRF across sex. Given these results, further experiments were conducted in a mix of both sexes.

### Time-restricted feeding on HFD reversed cortical and hippocampal spine changes

To investigate the dynamics of neuronal alterations accompanying memory restoration on TRF, we imaged *in vivo* remodelling of dendritic spines at the same three timepoints as described above (Fig. 5a). Comparisons between the 1st and 2nd images (week 8 vs. 12) indicated dynamic remodelling of dendritic spines due to TRF, while the persistence of this change was recorded in session 3 (week 12 vs. 13) (Fig. 5b). Previous studies on the same HFD model indicated that obesogenic diet during adolescence can *enhance* and *reduce* neuronal functions depending on the brain regions.¹⁰⁻¹² This prompted us to prepare optical imaging windows atop the sensory cortex (S1) and dorsal hippocampus (dCA1) as both activate during retrieval of episodic memory³⁰ in

<footnote>ANOVA for S1 (n = 8 mice with NC *ad libitum*, 9 with HF *ad libitum*, 7 with NC *restricted*, 9 with HF *restricted*): Effect of schedule $F_{(1,29)} = 12 p = 0.001$, diet $F_{(1,29)} = 22 p < 0.0001$, interaction $F_{(1,29)} = 5.4 p = 0.02$. Two-way ANOVA for CA1 (n = 8 mice with NC *ad libitum*, 8 with HF *ad libitum*, 5 with NC *restricted*, 9 with HF *restricted*): Effect of schedule $F_{(1,26)} = 4.6 p = 0.04$, diet $F_{(1,26)} = 7.7 p = 0.009$, interaction $F_{(1,26)} = 8 p = 0.008$. See Supplementary Table S1 for post-hoc analysis ***p < 0.001, analysis ****p < 0.0001 and effect size. g. Summary: HFD enhanced dCA1 activation, decreased S1 activation, and TRF reverted it.</footnote>
<figure><img src="image_23.png" /></figure>

**Fig. 5:** Downplaying *dCA1* activity trumps S1 deficits and memory impairment in mice fed obesogenic food **a.** Timeline. Clozapine-N-oxide (CNO as DREADD ligand) injected i.P. at 2 mg/kg 45 min before novel object recognition (NOR) testing. HC: high fat/sugar, NC: normal chow. **b.** Bilateral injections of hM3dq (DREADD activator: Gq) virus in somatosensory cortex S1 in males (n = 24) and females (n = 8). **c.** Transgene expression and CNO-evoked induction of c-Fos labelled with antibodies. Scale = 500 and 40 µm, respectively. **d.** % Time exploring the old vs. new objects in the NOR on week 12 (means ± SEM of n = 10 mice with NC ad libitum + vehicle, 7 with HF ad libitum + vehicle, 9 with NC ad libitum + CNO, 7 with HF ad libitum + CNO). Three-way ANOVA: Effect of diet x CNO x objects F(1,29) = 0.8 p = 0.3, effect of CNO x objects F(1,29) = 2.8 p = 0.1, effect of diet x objects F(1,29) = 0.4 p = 0.5, effect of objects F(1,29) = 15 p = 0.0005, effect of CNO F(1,29) = 54 p < 0.0001. See Supplementary Table S1 for post-hoc analysis \*\*p < 0.01, \*\*\*p < 0.001 and effect size. **e.** Bilateral injections of hM4di (DREADD inhibitor: Gi) virus in dorsal hippocampus subfield dCA1 in males (n = 16) and females (n = 10). **f.** Transgene expression and CNO-evoked repression of NOR-induced c-Fos labelled with antibodies. Scale = 250 and 65 µm, respectively. **g.** % Time exploring the old vs. new objects in the NOR on week 12 (means ± SEM of n = 6 mice with NC ad libitum + vehicle, 6 with HF ad libitum + vehicle, 7 with NC ad libitum + CNO, 7 with HF ad libitum + CNO). Three-way ANOVA: Effect of diet x CNO x objects F(1,22) = 3.8 p = 0.06, effect of CNO x objects F(1,22) = 331 p < 0.0001, effect of diet x objects F(1,22) = 0.3 p = 0.5, effect of objects F(1,22) = 28 p < 0.0001, effect of CNO F(1,22) = 80 p < 0.0001. See Supplementary Table S1 for post-hoc analysis \*\*p < 0.01, \*\*\*p < 0.001 and effect size. **h.** Bilateral injections of hM4di (or hM3dq) virus in dCA1 and S1 in males (n = 20) and females (n = 22). **i.** Transgene expression at 4 sites. Scale = 700 µm. **j.** % Time exploring the old vs. new objects in the NOR on week 12 (means ± SEM of n = 7 Sham controls with HF ad libitum + vehicle, 7 sham controls with HF ad libitum + CNO, 7 Gi mice with HF ad libitum + vehicle, 9 Gi with HF ad libitum + CNO, 7 Gq with HF ad libitum + vehicle, 7 Gq with HF ad libitum + CNO). Two-way ANOVA: Effect of objects F(1,12) = 0.09 p = 0.7, CNO F(1,12) = 3.6 p = 0.078, interaction F(1,12) = 2 p = 0.1. Three-way ANOVA: Effect of DREADD x CNO x objects F(1,26) = 0.04 p = 0.8, effect of CNO x objects F(1,26) = 0.24 p = 0.6, effect of DREADD x objects F(1,26) = 0.9 p = 0.3, effect of objects F(1,26) = 6.5 p = 0.016, effect of DREADD F(1,26) = 224 p < 0.0001. See Supplementary Table S1 for post-hoc analysis \*p < 0.05 and effect size. Gi: DREADD inhibitor, Gq: DREADD activator.
transgenic *Thy1*-YFP mice labelling sparse layer-5 pyramidal neurons with bright YFP-fluorescence. Mice use S1 layer-5 pyramidal neurons for detailed exploration (e.g. object texture-sensing)¹³ and dCA1 pyramidal neurons to form representation of tactile information while encoding episodic memory.⁴⁴

A comparison between imaging sessions 1 and 2 showed robust remodelling of dendritic spines often occurring in clusters within 5 µm distance in both S1 and dCA1 (Fig. 5c). The extent of changes was exceptionally high and region-specific in mice fed HFD. In particular, only dCA1 neurons increased spine addition (Fig. 5d) whereas only S1 neurons increased spine elimination in mice fed HFD ad libitum (Fig. 5e). ANOVA showed significant group-mean differences for spine additions (*p* < 0.0001) with a large effect size (*d* = 5.1) in dCA1 but not in S1 (*p* = 0.8, *d* = 0.1). Spine eliminations, on the other hand, showed no difference between groups in dCA1 (*p* = 0.4, *d* = 0.4), with only a significant effect in S1 (*p* < 0.0001, *d* = 6). The maintenance of pre-existing spines decreased in S1 significantly (*p* < 0.0001, *d* = 3.5) without being affected in dCA1 (*p* = 0.3, *d* = 0.8) (Fig. 5f), while newly-formed spine survival decreased in S1 (*p* = 0.004, *d* = 2.3) but increased in dCA1 (*p* = 0.004, *d* = 2.1) (Fig. 5g).

Strikingly, TRF on HFD reversed all these effects with significant difference between groups with large effect sizes (Supplementary Table S1). Specifically, TRF improved spine addition, lowered the extent of spine deletion and rescued new spine survival in S1 (Fig. 5d, e, g), while it prevented new spine additions and survival in dCA1 (Fig. 5d, g). The only exception was that TRF failed to change the reduced maintenance of pre-existing spines in S1 (ANOVA *p* < 0.0001, *d* = 2.8) (Fig. 5f), despite the increase of spine additions (ANOVA *p* = 0.003, *d* = 1.5) (Fig. 5d). Remarkably, the normalised dynamics of spine remodelling persisted in the 3rd imaging sessions of S1 and dCA1 on TRF while it remained altered on HFD ad libitum (Supplementary Fig. S1). Altogether, the results indicate that TRF corrected structural alterations of pyramidal neurons caused by HFD in S1 and dCA1.

## Time-restricted feeding on HFD reverted cortical and hippocampal activity changes

To confirm differential engagement of neurons in S1 vs. dCA1 suggested by dendritic spine remodelling, we harvested brains 1 h after NOR recall to quantify cFos immediate early gene induction in *Thy1*-YFP pyramidal neurons (Fig. 6a). The number of Fos-positive YFP-neurons decreased in S1 and increased in dCA1 with ad libitum HFD (Fig. 6b), with YFP-neuron proportion within Fos-activated cells only changing in dCA1 (Fig. 6c). ANOVA analysis showed significant differences between groups in dCA1 and S1 with large effect sizes (dCA1: *p* = 0.005, *d* = 1.7, S1: *p* = 0.005, *d* = 1.55). Hence, pyramidal neurons were contrastingly engaged

between S1 (*less*) and dCA1 (*more*) after recall, and remarkably, TRF reversed these effects (Fig. 6b). HFD-fed mice on TRF tend to show less activation in dCA1 (*p* = 0.07, *d* = 1.7) and significantly more in S1 (*p* = 0.0005, *d* = 2.12), also decreasing the proportion of YFP neurons within the population of Fos-activated cells in dCA1 (*p* = 0.0001, *d* = 1.88) (Fig. 6c).

Does HFD also affect re-activation of memory-encoding cells? To address this, cFos-positive cells were marked with a permanent genetic tracer in double-transgenic mice (Floxed-tdTomato crossed with Fos-TRAP2 (ER$^{T2}$-CRE). These animals were fed HFD ad libitum from week 1-to-8, and TRF initiated at adulthood from week 8-to-12. Tomato-tagging was induced by hydroxytamoxifen (4OH-TAM) injection immediately after NOR recall and before schedule change on week 8. Four weeks later during TRF, mice were retested in NOR (with the same objects and test conditions) and brains harvested 1 h later (Fig. 6d). Mice fed HFD ad libitum showed lesser re-engagement of NOR memory-encoding cells in S1 (Tomato$^+$/cFos$^+$ cells ANOVA *p* < 0.0001, *d* = 3.8) and greater reactivation in dCA1 (*p* = 0.0003, *d* = 2.5) (Fig. 6e). Remarkably, TRF corrected the engagement of Tomato$^+$ cells in dCA1 (ANOVA *p* = 0.0007, *d* = 1.9) and in S1 (*p* = 0.0001, *d* = 1.7) (Fig. 6e). Together, the results indicate that TRF on HFD re-engaged memory-activated cells *more* in S1 and *less* in dCA1.

## Corticohippocampal chemogenetic manipulation corrected HFD-induced memory deficits

We next used chemogenetics to determine causality between neuronal engagement and memory performance. In particular, we tested if reversing the contrasting patterns of change in S1 vs. dCA1 can correct memory in HFD-fed mice. Animals were bilaterally injected with Designer-Receptor-Exclusively-Activated-by-Designer-Drugs (DREADD) to activate (S1) or inhibit (dCA1) pyramidal neurons, targeted under a Camk2a promoter. The DREADD ligand CNO (or vehicle) was injected 45 min prior to NOR recall on week 12 (Fig. 3a).

In S1, hM3Dq-activation with CNO (Fig. 3b) induced cFos in infected cells (Fig. 3c, Supplementary Fig. S2), indicating increased engagement of S1 pyramidal neurons. HFD-fed mice improved object discrimination comparable to NC-fed controls when injected with CNO (ANOVA *p* = 0.009, *d* = 2.9) unlike with vehicle (*p* = 0.7, *d* = 0.23) (Fig. 3d).

In dCA1, on the other hand, we expressed the DREADD inhibitor hM4Di in pyramidal neurons (Fig. 3e), which decreased Fos-induction after CNO injection (Fig. 3f, Supplementary Fig. S3). HFD-fed mice improved object discrimination comparable to NC-fed controls when injected with CNO (ANOVA *p* = 0.0007, *d* = 3.1) unlike with vehicle (*p* = 0.3, *d* = 0.7) (Fig. 3g). Therefore, bi-directional effects of HFD on pyramidal neurons of S1
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**Fig. 6:** HFD-induced memory deficits associated with GR phosphorylation and function. a. Timeline in males (n = 43) during week 12: RU486 (GR antagonist) injected I.P. at 10 mg/kg immediately after novel object recognition (NOR) training. b. % Time exploring the old and new objects (means ± SEM of n = 12 mice with NC ad libitum + vehicle, 11 with HF ad libitum + vehicle, 12 with NC ad libitum + RU486, 8 with HF ad libitum + RU486). Three-way ANOVA: Effect of RU486 $F_{(1,39)} = 67$ p < 0.0001, effect of objects $F_{(1,39)} = 2.7$ p = 0.1, effect of diet $F_{(1,39)} = 0$ p = 0.9, effect of diet × objects $F_{(1,39)} = 0.9$ p = 0.3, effect of objects × X RU486 $F_{(1,39)} = 4.8$ p = 0.03, effect of diet × RU486 $F_{(1,39)} = 0$ p = 0.9, effect of diet × RU486 × objects $F_{(1,39)} = 0.7$ p = 0.3. See Supplementary Table S1 for post-hoc analysis \*p = 0.01. HC: high fat/sugar diet, NC: normal chow. c. Remodelling of dendritic spines in *Thy1-YFP* males (n = 28) fed normal chow *ad libitum*. Arrows point to dynamic spines. Scale = 3 µm. d. % Spine gains and losses (means ± SEM) in S1 (n = 16 mice) and dCA1 (n = 12 mice). Two-way ANOVA: interaction of spine dynamics and RU486 $F_{(1,20)} = 14.9$ p = 0.001 in S1. Kruskal-Wallis test p = 0.002 in CA1: Effect of RU486 on additions p = 0.003, eliminations p
(deactivation) and dCA1 (hyperactivation) are causal to
memory impairment, and reversible with chemogenetics.

Scaling hippocampal and cortical activities
corrected HFD-induced memory deficits

Next, we targeted DREADD expression in both S1 and dCA1 of the same mice to dissect their functional uncoupling in HFD-induced memory deficits (Fig. 3h). First, hM4Di-mediated inhibition in both S1 and dCA1 significantly improved memory (Fig. 3j, ANOVA CNO: *p* = 0.02, *d* = 1.7, Vehicle: *p* = 0.18, *d* = 0.9) compared to sham-injected, HFD-fed controls. This contrasted with hM3Dq-mediated activation of both S1 and dCA1 that failed to ameliorate memory performance in *ad libitum* HFD-fed mice (Fig. 3j, ANOVA CNO: *p* = 0.3, *d* = 0.5, Vehicle: *p* = 0.5, *d* = 0.5). This indicated that dCA1 activation occluded the beneficial effects of S1 activation in the HFD-model, and that down-scaling activity in dCA1pyramidal neurons was necessary and sufficient to correct memory retrieval.

Blocking GR recapitulates opposite effects in S1 and
dCA1 by HFD *ad libitum*

To investigate the underlying mechanism, we injected
the GR antagonist RU486, well-known modulator of
dendritic spine remodelling and object recognition
memory.⁴⁵,⁴⁶ We tracked the remodelling of dendritic
spines in S1 and dCA1 when RU486 was injected
immediately after NOR training (Fig. 4a) as it impaired
memory retention 24 h later (ANOVA *p* = 0.01, Fig. 4b).
Imaging 7-day spine turnover on week 12 (Fig. 4c)
showed that RU486 inverted the ratio of additions vs.
eliminations compared to vehicle-injected controls, by
enhancing net loss of spines in S1 and gains in dCA1
(Kruskal–Wallis test *p* = 0.03, Fig. 4d), similar to the
effect of HFD *ad libitum* (Fig. 5c and d). We harvested
brains 1 h after NOR for histological examination of GR
signalling markers dependent on glucocorticoids
(pS226), or BDNF (pS134)⁴⁷ (Fig. 4e). Strikingly, pS134
levels decreased in S1 but increased in dCA1 of
HFD-fed mice, while TRF reversed these opposite
effects (Fig. 4f) without changing GR levels
(Supplementary Fig. S4). In contrast, TRF failed to
revert HFD-induced changes of pS226 (Fig. 4g). These
results suggest that specific components of GR signal-
ling could be downregulated in S1 and upregulated in
dCA1 by HFD *ad libitum*.

GR phosphorylation promotes memory retention
by TRF on obesogenic food

We next used mouse carriers of S134A constitutive knock-in mutation (previously described¹¹) to first determine the role of pS134-mediated signalling on the feeding-fasting cycle. Mutant mice had normal locomotor activity and anxiety despite an effect on body weight gain (ANOVA for the interaction of genotype with diet and sex *p* = 0.03 but not with TRF *p* = 0.7, Supplementary Fig. S5 and Table S1). Brains collected 1 h after NOR recall showed lesser Fos-induction in S1 (Fig. 7a) and more in dCA1 (Fig. 7b) compared to WT controls, regardless of diet and meal scheduling, suggesting a lack of pS134 occluded the aversive effects of HFD and prevented the beneficial effects of TRF. Behaviourally, mutant mice exhibited NOR memory deficits early (Fig. 7c) that persisted on weeks 8 and 12 thereby mimicking the effect of HFD (Fig. 7d and e). Yet, TRF failed to correct memory deficits in HFD-fed mutant mice contrary to wildtype controls, suggesting that pS134 is required for recognition memory (Fig. 7e).

Finally, we tested emotional memory in mutant mice using contextual fear conditioning. Although acquisition was undistinguishable between genotypes (Fig. 7f), freezing behaviour was reduced in mutants specifically during recall of context (Fig. 7g). Again, TRF had no effect in the mutants, suggesting that pS134 is also required for emotional memory.

Discussion

The present study shows that cortico-hippocampal activ-
ities necessary for remembering are uncoupled by obe-
sogenic food consumed *ad libitum* but not on meal
scheduling. Similar cortico-hippocampal mechanisms for
memory retrieval previously involved the parietal cortex
(PC) of mice and humans.³⁰ Interestingly, not only do
neuroimaging studies in PC-lesioned individuals
revealed its active role in memory retrieval,³⁰ but also in
typically developing children where co-activation of PC-
hippocampus axis is seen upon exposure to food.⁴⁸ Che-
mogenetic manipulations in mice proved that cortical
mechanisms are sufficient for remembering.⁴⁹ We pre-
dict that cortical pathways regulate attentional states and
stabilise behavioural representations in the hippocam-
pus,⁵⁰ which is disrupted by HFD.

= 0.08. See Supplementary Table S1 post-hoc analysis \*\*p < 0.01. e. GR phosphorylation at sites dependent (S226) and independent (S134) of glucocorticoids in males (n = 30). f. Intensity (means ± SEM) of p-GR S134 in S1 (n = 11 mice) and dCA1 (n = 12 mice). Purple = TRF, black = *ad libitum*. Two-way ANOVA for S1 data: Effect of diet *F*<sub>(1,11)</sub> = 1 *p* = 0.3, TRF *F*<sub>(1,11)</sub> = 4.5 *p* = 0.05, interaction *F*<sub>(1,10)</sub> = 7.9 *p* = 0.01. For CA1 data: Effect of diet *F*<sub>(1,8)</sub> = 25 *p* = 0.001, TRF *F*<sub>(1,8)</sub> = 12.5 *p* = 0.007, interaction *F*<sub>(1,8)</sub> = 4.5 *p* = 0.06. See Supplementary Table S1 for post-hoc analysis \*p < 0.05. TRF: time restricted feeding, ad lib: ad libitum. g. Intensity (means ± SEM) of p-GR S226 in S1 (n = 12 mice) and dCA1 (n = 10 mice). Purple = TRF, black = *ad libitum*. Kruskal–Wallis test *p* = 0.7 for S1 data. Two-way ANOVA for CA1 data: Effect of diet *F*<sub>(1,10)</sub> = 0.8 *p* = 0.3, TRF *F*<sub>(1,10)</sub> = 0.6 *p* = 0.4, interaction *F*<sub>(1,10)</sub> = 0.01 *p* = 0.9. See Supplementary Table S1 post-hoc analysis \*p < 0.05.
<figure><img src="image_30.png" /><figcaption>**Fig. 7:** GR phosphorylation promotes memory retention by TRF in mice fed obesogenic food. **a.** Fos induction in S1 1 h after object recognition memory test (means ± SEM, n = 16 WT GR<sup>S134/S134</sup> and 16 mutants GR<sup>A134/A134</sup> homozygotes). Three-way ANOVA: Effect of genotype *F*<sub>(1,24)</sub> = 24 p < 0.0001; interaction of diet and regimen *F*<sub>(1,24)</sub> = 4.3 *p* = 0.04 post-hoc analysis \* *p* < 0.05, \*\* *p* < 0.01. See Supplementary Table S1 for details. HC: high fat/sugar diet, NC: normal chow, TRF: time restricted feeding. **b.** Fos induction in dCA1 1 h after object recognition memory test (means ± SEM, n = 16 WT, 14 mutants). Three-way ANOVA: Effect of genotype *F*<sub>(1,22)</sub> = 5.4 *p* = 0.02; interaction of diet and genotype *F*<sub>(1,22)</sub> = 5 *p* = 0.03 post-hoc analysis \* *p* < 0.05, \*\* *p* < 0.01. See Supplementary Table S1 for details. **c.** % Time exploring the old and new objects 24 h after the training. Data are means ± SEM of n = 55 WT GR<sup>S134/S134</sup> homozygotes (n = 24 males, 31 females) and 42 mutants GR<sup>A134/A134</sup> homozygotes (n = 24 males, 18 females). Three-way ANOVA: Effect of sex *F*<sub>(1,54)</sub> = 0.1 *p* = 0.7, genotype *F*<sub>(1,54)</sub> = 0.1 *p* = 0.7, effect of objects *F*<sub>(1,54)</sub> = 17 *p* < 0.0001. Consolidated 2-way ANOVA without sex factor: Effect of genotype *F*<sub>(1,95)</sub> = 0.9 *p* = 0.3, effect of objects *F*<sub>(1,95)</sub> = 9.2 *p* = 0.003, interaction *F*<sub>(1,95)</sub> = 32 *p* < 0.0001. See Supplementary Table S1 for post-hoc analyses \*\*\* *p* < 0.001 and effect size. **d.** % Time exploring the old and new objects 24 h after the training. Data are means ± SEM of n = 24 WT NC (n = 9 males, 15 females), 25 WT HF (n = 12 males, 13 females), 21 mutants NC (n = 13</figcaption></figure>
Our longitudinal approach showed a reversal of behavioural and structural correlates of memory in the *same mice* after a change of feeding-fasting cycle, compared to feeding obesogenic food *ad libitum* around the clock. We report an excessive engagement of pyramidal neurons in dCA1 and disengagement in S1 with converging lines of evidence (Fos-induction, engramme-trapping, dendritic spine maintenance). In agreement, Golgi-stained dCA1 neurons also showed higher densities of dendritic spines in adult mice fed HFD since adolescence⁵¹ associated with enhanced hippocampal long term potentiation (LTP).⁴¹ Additionally, TRF on HFD did not change overall dCA1 spine density either in Golgi-stained neurons⁵¹ or in *Thy1-YFP* neurons. However, we noted a specific improvement in turnover of newly formed spines, in agreement with the normalisation of LTP by TRF.²²

One striking observation is that HFD triggered bidirectional changes during peri-adolescence, persisting into adulthood. *Inhibiting* dCA1 hyperexcitation before retrieval corrected memory impairment in HFD-fed mice,⁴⁰,⁴² consistent with previous findings on emotional memories.⁵² Thus, optimal dCA1 excitation is necessary to retrieve contextual memories. Conversely, chronic gain of excitation bilaterally throughout dCA1 previously caused severe amnesia,⁵² similar to HFD-induced aberrant activity and LTP in dCA1.⁹,⁴¹,⁴² In S1, on the other hand, chemogenetic *activation* of pyramidal neurons only improved memories in HFD-fed mice, but not in controls. Together, it can be predicted that

augmenting S1 activity could moderate dCA1 activity as previously shown with multi-unit recordings.⁵³ HFD-fed mice showed uncoupling between a weakened S1 and hyperactivated dCA1. We confirmed that scaling activities between S1 and dCA1 is critical using cross-regional DREADD experiments, wherein partial inhibition of S1 and dCA1 was sufficient to remember despite HFD *ad libitum*. Conversely, partial excitation of both S1 and dCA1 failed to improve HFD-induced memory deficits. Thus, downscaling hyperactive dCA1 was both necessary and sufficient to improve long-term memory. This result is consistent with a previous study showing that the most stable populations of dCA1 pyramidal neurons in terms of dendritic spine remodelling to sensory stimulation- are the ones engaged in neural representations of behaviours.⁵⁴ Therefore, the issue with eating too rich a diet for too long might come down to how dCA1 activity is shaped by multiple convergent streams of information that participate in creating an integrated neuronal representation of exploratory behaviours.³⁰

Our findings in mice are also in agreement with co-activated hippocampus and sensory cortex in response to energy-dense food in neurotypical human participants,⁵⁵,⁵⁶ a response that is uncoupled after a meal in children with obesity as compared to children with normal weight.⁵⁷ We showed that prolonged consumption of energy-dense food in mice triggered region-specific changes in neuroplasticity that biased glucocorticoid phospho-signalling. Increased levels of

males, 8 females), 21 mutants HF (n = 11 males, 10 females). Four-way ANOVA: Effect of sex *F*(1,166) = 0 *p* > 0.9, genotype *F*(1,166) = 0 *p* > 0.9, effect of objects *F*(1,166) = 0 *p* > 0.9, effect of diet *F*(1,166) = 0 *p* > 0.9, sex X objects *F*(1,166) = 2 *p* = 0.08, sex X genotype *F*(1,166) = 0 *p* > 0.9, sex X diet *F*(1,166) = 0 *p* > 0.9, genotype X objects *F*(1,166) = 38 *p* < 0.0001, objects X diet *F*(1,166) = 110 *p* < 0.0001, genotype X diet *F*(1,166) = 0 *p* > 0.9, sex X genotype X objects *F*(1,166) = 2 *p* = 0.1, sex X genotype X diet *F*(1,166) = 0 *p* > 0.9, sex X diet X objects *F*(1,166) = 0.08 *p* = 0.7, genotype X diet X objects *F*(1,166) = 52 *p* < 0.0001, sex X genotype X diet X objects *F*(1,166) = 0.1 *p* = 0.7. Consolidated 3-way ANOVA without sex factor: Effect of genotype *F*(1,87) = 86 *p* < 0.0001, effect of objects *F*(1,87) = 0.4 *p* = 0.5, effect of diet *F*(1,87) = 1385 *p* < 0.0001, genotype X objects *F*(1,87) = 21 *p* < 0.0001, objects X diet *F*(1,87) = 51 *p* < 0.0001, genotype X diet *F*(1,87) = 265 *p* < 0.0001, genotype X diet X objects *F*(1,87) = 27 *p* = 0.0003. See Supplementary Table S1 for post-hoc analyses \*\*\*p < 0.001 and effect size. e. % Time exploring the old and new objects 24 h after the training. Data are means ± SEM of n = 9 WT NC ad lib (n = 3 males, 6 females), 15 WT NC TRF (n = 6 males, 9 females), 10 WT HF ad lib (n = 4 males, 6 females), 15 WT HF TRF (n = 7 males, 8 females), 10 mutants NC ad lib (n = 6 males, 4 females), 11 mutants NC TRF (n = 7 males, 4 females), 10 mutants HF ad lib (n = 4 males, 6 females), 11 mutants HF TRF (n = 7 males, 4 females). Five-way ANOVA: No main effects of single factors. Interaction of diet X objects *F*(1,108) = 80 *p* < 0.0001, genotype X object *F*(1,108) = 19 *p* < 0.0001, diet X schedule X object *F*(1,108) = 10 *p* = 0.001, diet X genotype X object *F*(1,108) = 30 *p* < 0.0001, diet X sex X schedule X object *F*(1,108) = 10 *p* = 0.01, diet X genotype X object X sex X schedule *F*(1,108) = 7.3 *p* = 0.008. See Supplementary Table S1 for post-hoc analysis \*\*p < 0.01, \*\*\*p < 0.001 and effect size. f. No effect of genotype, TRF or diet on freezing behaviour during fear conditioning. Data are means ± SEM of n = 10 WT NC ad lib (n = 4 males, 6 females), 11 WT NC TRF (n = 6 males, 5 females), 10 WT HF ad lib (n = 4 males, 6 females), 13 WT HF TRF (n = 6 males, 7 females), 12 mutants NC ad lib (n = 6 males, 6 females), 10 mutants NC TRF (n = 6 males, 4 females), 10 mutants HF ad lib (n = 4 males, 6 females), 8 mutants HF TRF (n = 5 males, 3 females). ANOVA: No effect of main factors or interactions. See Supplementary Table S1 for details. g. Effect of TRF % freezing behaviour 24 h post-conditioning in context A (without shocks) and context B (with the unpaired tone). Data are means ± SEM of n = 10 WT NC ad lib (n = 4 males, 6 females), 11 WT NC TRF (n = 6 males, 5 females), 10 WT HF ad lib (n = 4 males, 6 females), 13 WT HF TRF (n = 6 males, 7 females), 12 mutants NC ad lib (n = 6 males, 6 females), 10 mutants NC TRF (n = 6 males, 4 females), 10 mutants HF ad lib (n = 4 males, 6 females), 8 mutants HF TRF (n = 5 males, 3 females). Friedman's test *p* < 0.0001 indicates an effect of all factors with repeated measures (timepoints) validated with post-hoc Wilcoxon's test. Kruskal-Wallis test shows no effect of sex with context recall *p* = 0.9 but with tone recall *p* = 0.008 although the effect size with Cohen's *d* = 0.5 is neglectable. In contrast, there are significant effects of context with genotype *p* < 0.0001, with diet *p* = 0.0002 and with TRF *p* = 0.003. Pairwise group comparison indicates effects of genotypes, diet and TRF with large effect size. See Supplementary Table S1 for post-hoc analysis \*p < 0.05 and effect size.
corticosterone was detectable after 12 weeks of HFD in rats, associated with enhanced synaptic depression in CA1 neurons.⁵⁸ Pharmacological blockade with RU486 promoted net spine loss in S1 and gains in dCA1, perhaps due to the types of neurons and synapses involved.⁵⁹ Inhibiting GR action with RU486 post-learning previously ameliorated object location memory in rats fed HFD for 1 week,⁶⁰ contrary to what we find in mice fed HFD for 12 weeks, suggesting that GR signalling evolved between acute and chronic exposure to energy-dense food. For instance, HFD decreased brain-derived neurotrophic factor (BDNF) levels in the cortex along with cognitive impairments,⁶¹,⁶² which could bias GR phospho-signalling toward the S226-dependent pathway. Here, we show that HFD suppressed GR signalling via the S134-dependent pathway while bolstering the S226-dependent pathway. Experiments in mice lacking S134 occluded the effects of feeding-fasting cycle, suggesting it is required for bidirectional experience-dependent synaptic plasticity.¹³,⁶³ This is in agreement with HFD causing a circadian phase-shift in the expression of BDNF,⁶⁴ GR⁶⁵ and corticosterone levels.⁶⁶ Therefore, we propose that chronic HFD impeded the neurotrophic signalling of glucocorticoids¹⁷,⁵⁹,⁶⁷ in the cortico-hippocampal axis coupling attention with remembering. Promoting GR phosphorylation with inhibitors (or genetic invalidation) of the GR-phosphatase PP5 previously ameliorated adipogenesis and glucose tolerance induced by HFD⁶⁸,⁶⁹ but the effects on brain co-morbidities are yet to be explored.

In a recent transcriptomic study, we showed that the beneficial effects of 14 h TRF in the peri-adolescence HFD model also involved thyroid hormones and astrocytic-mediated regulation of glutamatergic transmission.⁷⁰ Cross-talk between thyroid and glucocorticoid signalling is well known, it remains to be investigated in this model to reinstate the cortico-hippocampal coupling that sustains long-term memory, and to confront obesity-related memory deficits.

The present set of observations do not exclude several alternate possibilities. For instance, it is possible that TRF could benefit all types of Western-style diets. It can also not be excluded that TRF benefits on cognition could involve GR in adipocytes and hepatocytes.⁷¹ Moreover, while we used the peri-adolescent HFD model because it is well characterised in terms of metabolic, neuroinflammatory and cognitive outcomes,²³,⁶⁰,⁷²⁻⁷⁴ TRF would also benefit other models such as when HFD started at adulthood or during gestation. For instance, gestational HFD caused protracted GR desensitisation to a corticosterone challenge in adulthood that amplified neuroinflammation.⁷⁵ Likewise, drug-induced GR desensitisation during gestation worsened glucose tolerance and inflammation by HFD after birth.⁷⁶ Thus, it cannot be excluded that TRF could benefit cognitive functioning in all age categories, nor predict lasting effects on shorter protocols nor after the

cessation of TRF. So far, only one study assessed the effects of one-week TRF, which was sufficient to improve short-term working memory in HFD-fed adult mice, but the effect on long-term memory was not tested.²² The involvement of glucocorticoid-binding to the mineralocorticoid receptor has not been tested and therefore cannot be excluded from the regulation of dendritic spine remodelling, learning and memory.⁴⁶,⁵⁹,⁶⁷ It cannot be excluded that cortico-hippocampal coupling is also necessary to retrieve remote memories (weeks/ months after learning) by TRF. Although the stability of memory performance has not been addressed post-TRF, the longitudinal sampling in the same mice (methodological strength of this study) was sufficient to demonstrate reversal in each animal that changed feeding-fasting cycle. Despite the remodelling of dendritic spines by TRF in the cortico-hippocampal axis, it cannot be excluded that sprouting dendritic spines harbour silent synapses like in the stressed amygdala,⁷⁷ which *in vivo* AMPA-uncaging could rule out as previously.³⁶ Finally, the lack of reciprocal direct glutamatergic projections between S1 and dCA1 indicates that cortico-hippocampal coupling could result from polysynaptic circuits modulating dCA1 responses to sensory stimulation possibly via the dentate gyrus-CA3-CA1 pathway, the subiculum-dCA1 pathway and also through thalamic inputs.⁴⁴ Future studies will advance the use of TRF beyond caveats and limitations.

**Contributors**

Conceptualisation: FJ, MPM, GF, EC; Methodology: YD, MAL, FJ, PC, AB, TSS; Investigations: YD, PC, EMA, AR; Funding acquisition: MPM, GF; Project supervision: FJ; Writing: FJ; Editing: PC, FJ, EC, GF, MPM. All authors approved the final manuscript.

**Data sharing statement**

Data are available without restriction on Zenodo https://zenodo.org/records/10953723.

**Declaration of interests**

EC, FJ, MPM received grant from ANR. GF and FJ received funding from FRC. All other authors declare no conflict of interest.

**Acknowledgements**

MPM (PI) and FJ, EC (Co-PI) acknowledge funding from ANR-21-CE14-0086. GF and FJ, EC (Co-PI) were supported by Fondation pour la Recherche sur le cerveau. AB and FJ acknowledges salary payment from CNRS. EC acknowledges funding from University of Strasbourg. EMA acknowledges funding from University of Montpellier. JCH, MPM, AR, GF received funding from INRAE. TSS, MAL, PC, YD acknowledge salary payments from Inserm. AR acknowledges salary payments from University of Bordeaux.

**Appendix A. Supplementary data**

Supplementary data related to this article can be found at https://doi.org/10.1016/j.ebiom.2025.105783.

**References**

1. Christakis NA, Fowler JH. The spread of obesity in a large social network over 32 years. *N Engl J Med.* 2007;357(4):370–379.
2 Meléndez-Fernández OH, Liu JA, Nelson RJ. Circadian rhythms disrupted by light at night and mistimed food intake alter hormonal rhythms and metabolism. *Int J Mol Sci.* 2023;24(4):3392.

3 Taillard J, Sagaspe P, Philip P, Bioulac S. Sleep timing, chronotype and social jetlag: impact on cognitive abilities and psychiatric disorders. *Biochem Pharmacol.* 2021;191:114438.

4 Longo VD, Panda S. Fasting, circadian rhythms, and time-restricted feeding in Healthy lifespan. *Cell Metab.* 2016;23(6):1048–1059.

5 Yokoyama Y, Nakamura TJ, Yoshimoto K, et al. A high-salt/high fat diet alters circadian locomotor activity and glucocorticoid synthesis in mice. *PLoS One.* 2020;15(5):e0233386.

6 Teeple K, Rajput P, Gonzalez M, Han-Hallett Y, Fernández-Juricic E, Casey T. High fat diet induces obesity, alters eating pattern and disrupts corticosterone circadian rhythms in female ICR mice. *PLoS One.* 2023;18(1):e0279209.

7 Janthakhin Y, Kingtong S, Juntapremjit S. Inhibition of glucocorticoid synthesis alleviates cognitive impairment in high-fat diet-induced obese mice. *Compr Psychoneuroendocrinology.* 2022;10:100130.

8 Gergerlioglu HS, Oz M, Demir EA, Nurullahoglu-Atalik KE, Yerlikaya FH. Environmental enrichment reverses cognitive impairments provoked by Western diet in rats: role of corticosteroid receptors. *Life Sci.* 2016;148:279–285.

9 Biyong EF, Alfos S, Dumetz F, et al. Dietary vitamin A supplementation prevents early obesogenic diet-induced microbiota, neuronal and cognitive alterations. *Int J Obes.* 2021;45(3):588–598.

10 Arango-Lievano M, Lambert WM, Bath KG, Garabedian MJ, Chao MV, Jeanneteau F. Neurotrophic-priming of glucocorticoid receptor signaling is essential for neuronal plasticity to stress and antidepressant treatment. *Proc Natl Acad Sci U S A.* 2015;112(51):15737–15742.

11 Graff J, Rei D, Guan JS, et al. An epigenetic blockade of cognitive functions in the neurodegenerating brain. *Nature.* 2012;483(7388):222–226.

12 Dromard Y, Arango-Lievano M, Borie A, et al. Loss of glucocorticoid receptor phosphorylation contributes to cognitive and neurocentric damages of the amyloid-β pathway. *Acta Neuropathol Commun.* 2022;10(1):91.

13 Arango-Lievano M, Borie AM, Dromard Y, et al. Persistence of learning-induced synapses depends on neurotrophic priming of glucocorticoid receptors. *Proc Natl Acad Sci U S A.* 2019;116(26):13097–13106.

14 Notaras M, Hill R, Gogos JA, Van Den Buuse M. BDNF Val66Met genotype determines hippocampus-dependent behavior via sensitivity to glucocorticoid signaling. *Mol Psychiatry.* 2016;21(6):730–732.

15 Arango-Lievano M, Lambert WM, Jeanneteau F. Molecular biology of glucocorticoid signaling. *Adv Exp Med Biol.* 2015;872:33–57.

16 Wosiski-Kuhn M, Erion JR, Gomez-Sanchez EP, Gomez-Sanchez CE, Stranahan AM. Glucocorticoid receptor activation impairs hippocampal plasticity by suppressing BDNF expression in obese mice. *Psychoneuroendocrinology.* 2014;42:165–177.

17 Jeanneteau F, Meijer OC, Moisan M. Structural basis of glucocorticoid receptor signaling bias. *J Neuroendocrinol.* 2023;35(2):e13203.

18 Lambert WM, Xu CF, Neubert TA, Chao MV, Garabedian MJ, Jeanneteau FD. Brain-derived neurotrophic factor signaling rewrites the glucocorticoid transcriptome via glucocorticoid receptor phosphorylation. *Mol Cell Biol.* 2013;33(18):3700–3714.

19 Currenti W, Godos J, Castellano S, et al. Association between time restricted feeding and cognitive status in older Italian adults. *Nutrients.* 2021;13(1):191.

20 Ooi TC, Meramat A, Rajab NF, et al. Intermittent fasting enhanced the cognitive function in older adults with mild cognitive impairment by inducing biochemical and metabolic changes: a 3-year progressive study. *Nutrients.* 2020;12(9):2644.

21 Gudden J, Arias Vasquez A, Bloemendaal M. The effects of intermittent fasting on brain and cognitive function. *Nutrients.* 2021;13(9):3166.

22 Davis JA, Paul JR, Yates SD, et al. Time-restricted feeding rescues high-fat-diet-induced hippocampal impairment. *iScience.* 2021;24(6):102532.

23 Boitard C, Etchamendy N, Sauvant J, et al. Juvenile, but not adult exposure to high-fat diet impairs relational memory and hippocampal neurogenesis in mice. *Hippocampus.* 2012;22(11):2095–2100.

24 Hernandez AR, Watson C, Federico QP, et al. Twelve months of time-restricted feeding improves cognition and alters microbiome

composition independent of macronutrient composition. *Nutrients.* 2022;14(19):3977.

25 Longo VD, Di Tano M, Mattson MP, Guidi N. Intermittent and periodic fasting, longevity and disease. *Nat Aging.* 2021;1(1):47–59.

26 Whittaker DS, Akhmetova L, Carlin D, et al. Circadian modulation by time-restricted feeding rescues brain pathology and improves memory in mouse models of Alzheimer's disease. *Cell Metab.* 2023;35(10):1704–1721.e6.

27 Chu CQ, Yu LL, Qi GY, et al. Can dietary patterns prevent cognitive impairment and reduce Alzheimer's disease risk: exploring the underlying mechanisms of effects. *Neurosci Biobehav Rev.* 2022;135:104556.

28 Mattson MP, Moehl K, Ghena N, Schmaedick M, Cheng A. Intermittent metabolic switching, neuroplasticity and brain health. *Nat Rev Neurosci.* 2018;19(2):63–80.

29 Choi JH, Sim SE, Kim JI, et al. Interregional synaptic maps among engram cells underlie memory formation. *Science.* 2018;360(6387):430–435.

30 Cabeza R, Ciaramelli E, Olson IR, Moscow M. The parietal cortex and episodic memory: an attentional account. *Nat Rev Neurosci.* 2008;9(8):613–625.

31 Arango-Lievano M, Jeanneteau F. Timing and crosstalk of glucocorticoid signaling with cytokines, neurotransmitters and growth factors. *Pharmacol Res.* 2016;113(Pt A):1–17.

32 Morales L, Del Olmo N, Valladolid-Acebes I, et al. Shift of circadian feeding pattern by high-fat diets is coincident with reward deficits in obese miceGaetani S, ed. *PLoS One.* 2012;7(5):e36139.

33 Chaix A, Zarrinpar A, Miu P, Panda S. Time-restricted feeding is a preventative and therapeutic intervention against diverse nutritional challenges. *Cell Metab.* 2014;20(6):991–1005.

34 Davis JA, Paul JR, Yates SD, et al. Time-restricted feeding rescues high-fat-diet-induced hippocampal impairment. *iScience.* 2021;24(6):102532.

35 Pennington ZT, Diego KS, Francisco TR, et al. ezTrack—a step-by-step guide to behavior tracking. *Curr Protoc.* 2021;1(10):e255.

36 Dromard Y, Arango-Lievano M, Fontanaud P, Tricaud N, Jeanneteau F. Dual imaging of dendritic spines and mitochondria in vivo reveals hotspots of plasticity and metabolic adaptation to stress. *Neurobiol Stress.* 2021;15:100402.

37 Ulivi AF, Castello-Waldow TP, Weston G, et al. Longitudinal two-photon imaging of dorsal hippocampal CA1 in live mice. *J Vis Exp.* 2019;19:148.

38 Arango-Lievano M, Giannoni P, Claeysen S, Marchi N, Jeanneteau F. Longitudinal in vivo imaging of the cerebrovasculature: relevance to CNS diseases. *J Vis Exp.* 2016;118. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28060355.

39 DeNardo LA, Liu CD, Allen WE, et al. Temporal evolution of cortical ensembles promoting remote memory retrieval. *Nat Neurosci.* 2019;22(3):460–469.

40 Naneix F, Bakoyiannis I, Santoyo-Zedillo M, et al. Chemogenetic silencing of hippocampus and amygdala reveals a double dissociation in periadolescent obesogenic diet-induced memory alterations. *Neurobiol Learn Mem.* 2021;178:107354.

41 Vouimba RM, Bakoyiannis I, Ducourneau EG, Maroun M, Ferreira G. Bidirectional modulation of hippocampal and amygdala synaptic plasticity by post-weaning obesogenic diet intake in male rats: influence of the duration of diet exposure. *Hippocampus.* 2021;31(2):117–121.

42 Bakoyiannis I, Ducourneau EG, N'diaye M, et al. Obesogenic diet induces circuit-specific memory deficits in mice. *Elife.* 2024;13:e80388.

43 Chen CC, Lu J, Yang R, Ding JB, Zuo Y. Selective activation of parvalbumin interneurons prevents stress-induced synapse loss and perceptual defects. *Mol Psychiatry.* 2018;23(7):1614–1625.

44 Pereira A, Ribeiro S, Wiest M, et al. Processing of tactile information by the hippocampus. *Proc Natl Acad Sci U S A.* 2007;104(46):18286–18291.

45 Okuda S, Roozendaal B, McGaugh JL. Glucocorticoid effects on object recognition memory require training-associated emotional arousal. *Proc Natl Acad Sci U S A.* 2004;101(3):853–858.

46 Liston C, Cichon JM, Jeanneteau F, Jia Z, Chao MV, Gan WB. Circadian glucocorticoid oscillations promote learning-dependent synapse formation and maintenance. *Nat Neurosci.* 2013;16(6):698–705.

47 Huzard D, Rappeneau V, Meijer OC, et al. Experience and activity-dependent control of glucocorticoid receptors during the stress response in large-scale brain networks. *Stress.* 2021;24(2):130–153.

48 Luo S, Alves J, Hardy K, et al. Neural processing of food cues in prepubertal children. *Pediatr Obes.* 2019;14(2):e12435.
49 Burianová H, Ciaramelli E, Grady CL, Moscovitch M. Top-down and bottom-up attention-to-memory: mapping functional connectivity in two distinct networks that underlie cued and uncued recognition memory. *Neuroimage*. 2012;63(3):1343-1352.

50 Aly M, Turk-Browne NB. Attention stabilizes representations in the human Hippocampus. *Cereb Cortex*. 2015;bhv041.

51 Valladolid-Acebes I, Fole A, Martín M, et al. Spatial memory impairment and changes in hippocampal morphology are triggered by high-fat diets in adolescent mice. Is there a role of leptin? *Neurobiol Learn Mem*. 2013;106:18-25.

52 Krueger JN, Wilmot JH, Teratani-Ota Y, et al. Amnesia for context fear is caused by widespread disruption of hippocampal activity. *Neurobiol Learn Mem*. 2020;175:107295.

53 Bellistri E, Aguilar J, Brotons-Mas JR, Foffani G, de la Prida LM. Basic properties of somatosensory-evoked responses in the dorsal hippocampus of the rat. *J Physiol*. 2013;591(10):2667-2686.

54 Castello-Waldow TP, Weston G, Ulivi AF, et al. Hippocampal neurons with stable excitatory connectivity become part of neuronal representationsCsicsvari J, ed. *PloS Biol*. 2020;18(11):e3000928.

55 Rapuano KM, Huckins JF, Sargent JD, Heatherton TF, Kelley WM. Individual differences in reward and somatosensory-motor brain regions correlate with adiposity in adolescents. *Cereb Cortex*. 2016;26(6):2602-2611.

56 Stice E, Yokum S, Burger KS, Epstein LH, Small DM. Youth at risk for obesity show greater activation of striatal and somatosensory regions to food. *J Neurosci*. 2011;31(12):4360-4366.

57 Bruce AS, Holsen LM, Chambers RJ, et al. Obese children show hyperactivation to food pictures in brain networks linked to motivation, reward and cognitive control. *Int J Obes*. 2010;34(10):1494-1500.

58 Pratchayasakul W, Kerdphoo S, Petsophonsakul P, Pongchaidecha A, Chattipakorn N, Chattipakorn SC. Effects of high-fat diet on insulin receptor function in rat hippocampus and the level of neuronal corticosterone. *Life Sci*. 2011;88(13):619-627.

59 Jeanneteau F, Coutellier L. The glucocorticoid footprint on the memory engram. *Curr Opin Endocr Metab Res*. 2022;25:100378.

60 Khazen T, Hatoum OA, Ferreira G, Maroun M. Acute exposure to a high-fat diet in juvenile male rats disrupts hippocampal-dependent memory and plasticity through glucocorticoids. *Sci Rep*. 2019;9(1):12270.

61 Kanoski SE, Meisel RL, Mullins AJ, Davidson TL. The effects of energy-rich diets on discrimination reversal learning and on BDNF in the hippocampus and prefrontal cortex of the rat. *Behav Brain Res*. 2007;182(1):57-66.

62 Molteni R, Barnard RJ, Ying Z, Roberts CK, Gómez-Pinilla F. A high-fat, refined sugar diet reduces hippocampal brain-derived neurotrophic factor, neuronal plasticity, and learning. *Neuroscience*. 2002;112(4):803-814.

63 Jeanneteau F, Borie A, Chao M, Garabedian M. Bridging the gap between BDNF and glucocorticoid effects on brain networks.

*Neuroendocrinology*. 2019. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30572337.

64 Genzer Y, Dadon M, Burg C, Chapnik N, Froy O. Effect of dietary fat and the circadian clock on the expression of brain-derived neurotrophic factor (BDNF). *Mol Cell Endocrinol*. 2016;430:49-55.

65 Quagliarini F, Mir AA, Balazs K, et al. Cistromic reprogramming of the diurnal glucocorticoid hormone response by high-fat diet. *Mol Cell*. 2019;76(4):531-545.e5.

66 Appiakannan HS, Kestyus DR, Weber ET. Effects of high fat diet and chronic circadian challenge on glucocorticoid regulation in C57BL/6J mice. *Physiol Behav*. 2019;204:100-105.

67 Jeanneteau F. Fast signaling by glucocorticoids shapes neural representations of behaviors. *Steroids*. 2023;199:109294.

68 Jacob W, Rosenzweig D, Vázquez-Martin C, Duce SL, Cohen PTW. Decreased adipogenesis and adipose tissue in mice with inactivated protein phosphatase 5. *Biochem J*. 2015;466(1):163-176.

69 Grankvist N, Amable L, Honkanen RE, Sjöholm Å, Ortsäter H. Serine/threonine protein phosphatase 5 regulates glucose homeostasis in vivo and apoptosis signalling in mouse pancreatic islets and clonal MIN6 cells. *Diabetologia*. 2012;55(7):2005-2015.

70 Helbling JC, Ginieis R, Mortessagne P, et al. Time-restricted feeding prevents memory impairments induced by obesogenic diet consumption in mice, in part through hippocampal thyroid hormone signaling. *Mol Metab*. 2024;6:102061.

71 Desarzens S, Faresse N. Adipocyte glucocorticoid receptor has a minor contribution in adipose tissue growth. *J Endocrinol*. 2016;230(1):1-11.

72 Tsan L, Décarie-Spain L, Noble EE, Kanoski SE. Western diet consumption during development: setting the stage for neurocognitive dysfunction. *Front Neurosci*. 2021;15:632312.

73 Murray S, Chen EY. Examining adolescence as a sensitive period for high-fat, high-sugar diet exposure: a systematic review of the animal literature. *Front Neurosci*. 2019;13:1108.

74 Reichelt AC, Rank MM. The impact of junk foods on the adolescent brain. *Birth Defects Res*. 2017;109(20):1649-1658.

75 Wijenayake S, Rahman MF, Lum CMW, De Vega WC, Sasaki A, McGowan PO. Maternal high-fat diet induces sex-specific changes to glucocorticoid and inflammatory signaling in response to corticosterone and lipopolysaccharide challenge in adult rat offspring. *J Neuroinflammation*. 2020;17(1):116.

76 Sheen JM, Hsieh CS, Tain YL, et al. Programming effects of prenatal glucocorticoid exposure with a postnatal high-fat diet in diabetes mellitus. *Int J Mol Sci*. 2016;17(4):533.

77 Suvrathan A, Bennur S, Ghosh S, Tomar A, Anilkumar S, Chattarji S. Stress enhances fear by forming new synapses with greater capacity for long-term potentiation in the amygdala. *Philos Trans R Soc Lond B Biol Sci*. 2014;369(1633):20130151.