Olfactory Contributions to Sleep-dependent Food Craving
Condition: Sleep Deprivation
MeSH terms: Sleep Deprivation
Study type: Interventional

Summary: 
      This within-subject experiment uses one night of acute sleep restriction (4h) vs normal sleep
      (8h) to study state-dependent changes in olfactory processing. Odor-evoked blood oxygen level
      dependent (BOLD) responses will be measured in olfactory brain regions using functional
      magnetic resonance imaging (fMRI). Food intake will be measured at a buffet.
    

Detailed description: 
      This randomized within-subject sleep-deprivation protocol is designed to examine the effects
      of reduced sleep on neural processing of food odors in olfactory brain areas. Subjects will
      be healthy, normal-weight subjects (N=30) with comparable regular sleep patterns. They will
      be pseudorandomly assigned to first participate in either the sleep deprived (SD) or the
      non-deprived (ND) session, and then undergo a 7-day sleep stabilization phase during which
      subjects will maintain a regular sleep schedule of 8 h (within pre-determined range of 10:30
      pm to 7:30 am). After sleep stabilization, subjects will either sleep normally (ND, 8h
      between 11pm and 7am), or sleep for only for 4h (SD, between 1am and 5am), at home. During
      the sleep stabilization phase and the night of sleep deprivation, sleep duration, as well as
      sleep and wakeup time will be recorded using actigraphy (ActiGraph, LLC, Pensacola, Florida).
      All subjects will participate in both sessions (SD and ND) with the two sessions being
      separated by 4 weeks. In the evening of the next day, olfactory fMRI will be conducted after
      dinner. Isocaloric meals will be provided during the 24h before fMRI and no beverages other
      than water will be permitted. After fMRI, subjects will have ad libitum access to
      high-caloric snacks in the form of an all-you-can-eat buffet.

      During initial screening, subjects will rate the pleasantness of six food odors, including
      three high-caloric sweet odors (caramel, yellow cake, ginger bread) and three high-caloric
      savory odors (potato chips, pot roast, garlic butter). Based on each participant's ratings,
      two sweet and two savory odors that are matched in pleasantness will be selected. In
      addition, two non-food control odors (fir needle and celery seed) will be used. On the
      evening after the sleep manipulation, subjects will arrive at the imaging center at 5:15pm,
      and will consume an isocaloric dinner at 6pm before entering the scanner at 7pm. Neuroimaging
      will be performed on a Siemens PRISMA system with a 64 channel head/neck coil, using imaging
      sequences optimized for signal recovery in olfactory and orbitofrontal cortices. Subjects
      will participate in 4 runs of olfactory stimulation inside the scanner and BOLD responses
      will be acquired with high spatial (2 mm isotopic) and temporal resolution (2000 ms). On each
      trial, subjects will be visually cued to sniff, and an odor (food or non-food) or
      non-odorized air will be delivered. Subsequently, subjects will rate the pleasantness or the
      intensity of the odor (pseudo-randomized). Sniffing will be measured using an fMRI-compatible
      breathing belt and spirometer. A high-resolution anatomical image will be acquired for the
      purpose of spatial normalization and anatomical localization of the fMRI responses.

      Upon arrival at the imaging center, a study study nurse will insert an intravenous sterile
      heparin-lock catheter in the left forearm vein and initiate blood sampling. Blood will be
      drawn every 30 min after arrival, resulting in 5 samples: before dinner, after dinner, before
      fMRI, during fMRI, and after fMRI.

      At the completion of fMRI, participants will be provided with a buffet where they have ad
      libitum access to high-caloric food items (sweet [mini muffins, cinnamon buns, chocolate chip
      cookies, and doughnut holes] and savory high-calorie snacks [pizza bites, potato chips, hash
      browns, garlic bread]). Subjects will be instructed to consume as much food as they like. All
      food items will be weighed pre- and post-consumption, and the consumed calories will be
      calculated.
    

Intervention name(s): Sleep-Deprived; Non-Sleep Deprived
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Sleep for 4 hours at home.; Sleep for 8 hours at home.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science