Premium
Memory encoding‐related anterior hippocampal potentials are modulated by deep brain stimulation of the entorhinal area
Author(s) -
Hansen Niels,
Chaieb Leila,
Derner Marlene,
Hampel Kevin G.,
Elger Christian E.,
Surges Rainer,
Staresina Bernhard,
Axmacher Nikolai,
Fell Juergen
Publication year - 2018
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.22808
Subject(s) - entorhinal cortex , hippocampus , hippocampal formation , neuroscience , psychology , parahippocampal gyrus , amygdala , deep brain stimulation , temporal lobe , epilepsy , medicine , disease , parkinson's disease
Background Deep brain stimulation (DBS) of the human entorhinal area using 50 Hz pulses has revealed conflicting results regarding memory performance. Moreover, its impact on memory‐related hippocampal potentials has not yet been investigated. Methods We recorded data from seven epilepsy patients implanted with depth electrodes in the entorhinal cortex, hippocampus, amygdala, and parahippocampal cortex. Entorhinal DBS (bipolar, biphasic 50 Hz pulses, on‐ and off‐cycles of 15 s) was applied with low amplitude (0.1 mA) to resemble physiologic conditions. During DBS on‐ and off‐periods, patients learned noun‐color associations that were later tested. Results During entorhinal DBS we observed more positive deflections of event‐related potentials (ranging from 700 to 950 ms) in the anterior hippocampus for the on‐ vs. off‐condition. We detected no effects in the amygdala, mid hippocampus and parahippocampal cortex. On the behavioral level, no differences in memory performance (item and source memory) were apparent in the on‐ vs. off‐condition, neither across all trials nor across patients. Discussion Our findings indicate that entorhinal DBS with low amplitude has an impact on memory encoding‐related potentials within the anterior hippocampus, but not on memory performance per se.