DOI: 10.5061/dryad.573n5tbn2
title: Data from: Dual transcranial electromagnetic stimulation of the precuneus boosts human long-term memory

description: Non-invasive brain stimulation techniques have the potential to improve
 memory functions. However, the results so far have been relatively modest
 and time-consuming. Here, we implemented a novel 3-minute combination of
 personalized repetitive transcranial magnetic stimulation (intermittent
 theta burst-iTBS) coupled with simultaneous application of gamma
 transcranial alternating current stimulation (γtACS) over the precuneus, a
 brain area connected to the hippocampus, to modulate long-term memory in
 healthy subjects. Only dual electromagnetic stimulation of the precuneus
 produced an increase in long-term associative memory as compared to iTBS
 alone and sham conditions in a sample of healthy volunteers. The effects
 were replicated in another independent sample, in which the increased
 associative memory was retained for up to one week. Moreover, dual
 stimulation increased gamma oscillations and functional connectivity
 between the precuneus and hippocampus through the white matter tracts that
 link the precuneus to the temporal lobe. These findings suggest that dual
 stimulation may lead to neuronal assemblies in a state favorable for
 enhancing long-term plasticity. Personalized dual electromagnetic
 stimulation of the precuneus may represent a new powerful approach for
 enhancing memory functions in several healthy and clinical conditions.
description: # Data from: Dual transcranial electromagnetic stimulation of the
 precuneus boosts human long-term memory Dataset DOI:
 [10.5061/dryad.573n5tbn2](10.5061/dryad.573n5tbn2) ## Description of the
 data and file structure Non-invasive brain stimulation techniques have the
 potential to improve memory functions. However, the results so far have
 been relatively modest and time-consuming. Here, we implemented a novel
 3-minute combination of personalized repetitive transcranial magnetic
 stimulation (intermittent theta burst-iTBS) coupled with simultaneous
 application of gamma transcranial alternating current stimulation (γtACS)
 over the precuneus, a brain area connected with the hippocampus, to
 modulate long-term memory in healthy subjects. We conducted four
 experiments aimed at understanding the effects of dual iTBS+γtACS on
 associative memory performance, cortical oscillatory activity and
 functional connectivity. ### Files and variables **File: EXP1_STMB.xlsx**
 **Description:** This file contains the short-term memory binding test
 (STMB) data performed in experiment 1. The test was administered three
 times after three stimulation conditions (iTBS+sham-γtACS;
 sham-iTBS+sham-γtACS; iTBS+γtACS). STMB is a recognition task relying on a
 change detection paradigm. Participants were instructed to remember visual
 arrays of three black shapes (shape) or colored shapes (binding) presented
 for 2 seconds (study phase). After a 1-second delay where a blank screen
 was presented (retention interval), a display with the same or different
 items appeared in new random locations on the screen (test phase). 
 **Variables** * Accuracy (ACC), expressed in percentage, and reaction
 times (RT), expressed in ms, are reported for each stimulation condition
 (iTBS+sham-γtACS; sham-iTBS+sham-γtACS; iTBS+γtACS) and condition of the
 test (shape; binding). Each row corresponds to a study participant.
 **File: EXP2_STMB.xlsx** **Description:** This file contains
 the short-term memory binding test (STMB) data performed in experiment 2.
 The test was administered two times after two stimulation conditions
 (iTBS+sham-γtACS; iTBS+γtACS). STMB is a recognition task relying on a
 change detection paradigm. Participants were instructed to remember visual
 arrays of three black shapes (shape) or colored shapes (binding) presented
 for 2 seconds (study phase). After a 1-second delay where a blank screen
 was presented (retention interval), a display with the same or different
 items appeared in new random locations on the screen (test phase). 
 **Variables** * Accuracy (ACC), expressed in percentage, and reaction
 times (RT), expressed in ms, are reported for each stimulation condition
 (iTBS+sham-γtACS; iTBS+γtACS) and condition of the test (shape;
 binding). Each raw correspond to a study participant. **File:
 EXP3_TMS-EEG.xlsx** **Description:** This file contains cortical
 oscillations data collected in experiment 3 through the combination of
 transcranial magnetic stimulation (TMS) and electroencephalography (EEG)
 performed over the precuneus and the left posterior parietal cortex in
 response to two stimulation conditions (iTBS+sham-γtACS; iTBS+γtACS). To
 assess the effects of the stimulation, the TMS-EEG was performed before
 (T0), just after (T1), and after 20 minutes from the stimulation (T2).
 Theta (θ), alpha (α), beta (β), low gamma (γ), and high gamma (highγ)
 oscillatory activity were investigated. **Variables** * The oscillatory
 power (µV^2^) obtained by the subtraction of T1 to T0 (ΔT1) and T2 to T0
 (ΔT2) is reported for each frequency band (θ, α, β, γ, highγ) and
 stimulation condition (iTBS+sham-γtACS; iTBS+γtACS). The first sheet
 (DELTA PC) reports the oscillatory power of the TMS-EEG performed over the
 precuneus, the second sheet (DELTA L-PPC) reports the oscillatory power of
 the TMS-EEG performed over the left posterior parietal cortex. Each raw
 correspond to a study participant. **File: EXP1_FNAT.xlsx**
 **Description:** This file contains the face-name associative task (FNAT)
 data performed in experiment 1. The test was administered three times
 after three stimulation conditions (iTBS+sham-γtACS; sham-iTBS+sham-γtACS;
 iTBS+γtACS). FNAT, evaluating long-term associative memory, consisted of a
 learning phase followed by immediate and delayed recalls and recognition
 trial. During the learning phase, participants were asked to learn 12
 faces associated with a name and an occupation. Right after the learning
 phase, there was an immediate cued recall phase, in which the participants
 were asked to recall the name and the occupation of each face previously
 shown while observing the faces again. The delayed cued recall consisted
 of showing the same faces and asking participants to say each name and
 occupation. During the recognition trial, participants were asked to
 recognize the correct name and/or occupation among three alternatives
 each. **Variables** * FNAT accuracy is reported with a percentage index
 for the sum of names correctly associated with the face (NAME), the sum of
 occupations correctly associated with the face (OCCUP) and the sum of
 items where both name and occupation were correctly associated to the face
 (TOT). These indices are reported for each task phase (immediate, delayed
 and recognition) and each stimulation condition (iTBS+sham-γtACS;
 sham-iTBS+sham-γtACS; iTBS+γtACS). **File: EXP2_FNAT.xlsx**
 **Description:** This file contains the face-name associative task (FNAT)
 data performed in experiment 2. FNAT was administered two times after two
 stimulation conditions (iTBS+sham-γtACS; iTBS+γtACS). FNAT, evaluating
 long-term associative memory, consisted of a learning phase followed by
 immediate and three delayed recalls and recognition trial. During the
 learning phase, participants were asked to learn 12 faces associated with
 a name and an occupation. Right after the learning phase, there was an
 immediate cued recall phase, in which the participants were asked to
 recall the name and the occupation of each face previously shown while
 observing the faces again. The delayed cued recall, performed after 15
 minutes (delayed), 24 hours (delayed24) and 7 days (delayed7d), consisted
 of showing the same faces and asking participants to say each name and
 occupation. In the recognition trial, participants were asked to recognize
 the correct name and/or occupation among three alternatives each.
 **Variables** * FNAT accuracy is reported with a percentage index for the
 sum of names correctly associated with the face (NAME), the sum of
 occupations correctly associated with the face (OCCUP) and the sum of
 items where both name and occupation were correctly associated to the face
 (TOT). These indices are reported for each task phase (immediate,
 delayed, delayed24, delayed7d and recognition) and each stimulation
 condition (iTBS+sham-γtACS; sham-iTBS+sham-γtACS; iTBS+γtACS). #### File:
 EXP4_RM.xlsx **Description:** This file contains data about functional
 connectivity between the precuneus and hippocampus acquired with
 experiment 4. fMRI was acquired before and after two stimulation
 conditions (iTBS+sham-γtACS; iTBS+γtACS). **Variables** *  Functional
 connectivity between the precuneus and the hippocampus is reported before
 and after iTBS+sham-γtACS and iTBS+γtACS. ## Human subjects data We
 confirm that all participants gave explicit consent to publish the
 de-identified data. All data were de-identified assigning a code to each
 participant.