NYU Langone Health, Department of Neurology, New York, NY 10017, USA.
NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA.
Brain. 2021 Jun 22;144(5):1590-1602. doi: 10.1093/brain/awab044.
We describe the spatiotemporal course of cortical high-gamma activity, hippocampal ripple activity and interictal epileptiform discharges during an associative memory task in 15 epilepsy patients undergoing invasive EEG. Successful encoding trials manifested significantly greater high-gamma activity in hippocampus and frontal regions. Successful cued recall trials manifested sustained high-gamma activity in hippocampus compared to failed responses. Hippocampal ripple rates were greater during successful encoding and retrieval trials. Interictal epileptiform discharges during encoding were associated with 15% decreased odds of remembering in hippocampus (95% confidence interval 6-23%). Hippocampal interictal epileptiform discharges during retrieval predicted 25% decreased odds of remembering (15-33%). Odds of remembering were reduced by 25-52% if interictal epileptiform discharges occurred during the 500-2000 ms window of encoding or by 41% during retrieval. During encoding and retrieval, hippocampal interictal epileptiform discharges were followed by a transient decrease in ripple rate. We hypothesize that interictal epileptiform discharges impair associative memory in a regionally and temporally specific manner by decreasing physiological hippocampal ripples necessary for effective encoding and recall. Because dynamic memory impairment arises from pathological interictal epileptiform discharge events competing with physiological ripples, interictal epileptiform discharges represent a promising therapeutic target for memory remediation in patients with epilepsy.
我们描述了 15 名接受侵入性 EEG 的癫痫患者在进行联想记忆任务时皮质高频活动、海马棘波活动和癫痫样放电的时空过程。成功的编码试验表现出海马和额叶区域显著增加的高频活动。与失败的反应相比，成功的提示回忆试验表现出持续的海马高频活动。在成功的编码和检索试验中，海马的棘波率更高。在编码过程中出现的癫痫样放电与海马记忆减少 15%（95%置信区间 6-23%）有关。在检索过程中，海马的癫痫样放电预示着记忆减少 25%（15-33%）。如果癫痫样放电发生在编码的 500-2000ms 窗口内，记忆的可能性会降低 25-52%，如果在检索期间发生，则降低 41%。在编码和检索过程中，海马的癫痫样放电后棘波率会短暂下降。我们假设，癫痫样放电通过减少对有效编码和回忆至关重要的生理海马棘波，以区域和时间特异性的方式损害联想记忆。由于动态记忆障碍是由与生理棘波竞争的病理性癫痫样放电事件引起的，因此癫痫样放电是癫痫患者进行记忆矫正的一个很有前途的治疗靶点。
