Department of Epileptology, University of Bonn, Bonn D-53105, Germany.
Department of Psychology, University of Birmingham, United Kingdom.
Hippocampus. 2018 Jan;28(1):12-17. doi: 10.1002/hipo.22808. Epub 2017 Oct 30.
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.
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.
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.
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.
使用 50Hz 脉冲对人类内嗅区进行深度脑刺激 (DBS) 研究表明，其对记忆表现的影响结果相互矛盾。此外，其对与记忆相关的海马电位的影响尚未得到研究。
我们记录了 7 名癫痫患者的数据，这些患者的深度电极植入内嗅皮质、海马体、杏仁核和海马旁回。采用低幅度（0.1mA）的双极、双相 50Hz 脉冲进行内嗅 DBS（on- 和 off- 周期为 15s），以模拟生理条件。在 DBS 的 on- 和 off- 周期期间，患者学习名词-颜色联想，随后进行测试。
在进行内嗅 DBS 时，我们观察到在前海马体中，事件相关电位的正偏移（范围为 700 至 950ms）在 on- 条件下比 off- 条件下更为明显。我们在杏仁核、中海马体和海马旁回中没有检测到任何影响。在行为水平上，在 on- 条件下，无论是在所有试验还是在所有患者中，记忆表现（项目和来源记忆）都没有差异。
我们的发现表明，低幅度的内嗅 DBS 对内嗅前海马体的记忆编码相关电位有影响，但对记忆表现本身没有影响。
