%0 Journal Article
%A Ehrhardt, Nina M
%A Hanna, Jevri
%A Hayek, Dayana
%A Fleischmann, Robert
%A Grittner, Ulrike
%A Thielscher, Axel
%A Flöel, Agnes
%A Antonenko, Daria
%T Memory dependent modulation of hippocampal theta power through frontoparietal phase synchronous brain stimulation.
%J Scientific reports
%V 15
%N 1
%@ 2045-2322
%C [London]
%I Springer Nature
%M DZNE-2025-00893
%P 26504
%D 2025
%X Targeting subcortical regions like the hippocampus with non-invasive brain stimulation is challenging due to predominantly cortical distribution of electric fields. Frontoparietal phase-synchronous transcranial alternating stimulation (tACS) offers a promising approach to modulate hippocampal functions, though its ability to induce modulation of oscillatory activity in deep subcortical targets remains to be shown. In this pilot study, we applied dual-site theta-tACS (in-phase between left frontoparietal regions) during a temporal order memory task. To quantify hippocampal activity and connectivity, we performed subcortical source analyses of electroencephalography (EEG) data using a hierarchical subspace pursuit algorithm. While memory did not differ between tACS and sham conditions, we observed tACS-induced increases in hippocampal theta power and its connectivity in individuals with superior memory performance. This study provides first-time evidence that phase-synchronized tACS over lateral frontoparietal areas influences hippocampal theta oscillatory activity, substantiating its potential to modulate hippocampal functions in health and disease.
%K Hippocampus: physiology
%K Humans
%K Male
%K Theta Rhythm: physiology
%K Female
%K Adult
%K Parietal Lobe: physiology
%K Frontal Lobe: physiology
%K Memory: physiology
%K Electroencephalography
%K Transcranial Direct Current Stimulation: methods
%K Young Adult
%K Pilot Projects
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:40695870
%R 10.1038/s41598-025-09841-y
%U https://pub.dzne.de/record/280056