TY  - JOUR
AU  - Ehrhardt, Nina M
AU  - Hanna, Jevri
AU  - Hayek, Dayana
AU  - Fleischmann, Robert
AU  - Grittner, Ulrike
AU  - Thielscher, Axel
AU  - Flöel, Agnes
AU  - Antonenko, Daria
TI  - Memory dependent modulation of hippocampal theta power through frontoparietal phase synchronous brain stimulation.
JO  - Scientific reports
VL  - 15
IS  - 1
SN  - 2045-2322
CY  - [London]
PB  - Springer Nature
M1  - DZNE-2025-00893
SP  - 26504
PY  - 2025
AB  - 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.
KW  - Hippocampus: physiology
KW  - Humans
KW  - Male
KW  - Theta Rhythm: physiology
KW  - Female
KW  - Adult
KW  - Parietal Lobe: physiology
KW  - Frontal Lobe: physiology
KW  - Memory: physiology
KW  - Electroencephalography
KW  - Transcranial Direct Current Stimulation: methods
KW  - Young Adult
KW  - Pilot Projects
LB  - PUB:(DE-HGF)16
C6  - pmid:40695870
DO  - DOI:10.1038/s41598-025-09841-y
UR  - https://pub.dzne.de/record/280056
ER  -