Department of Neurology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Institute of Brain Science and Department of Physiology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China.
Brain Connect. 2022 Sep;12(7):660-669. doi: 10.1089/brain.2021.0046. Epub 2021 Sep 24.
Patients with postacute anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis are often left with permanent memory impairments. Given that NMDA receptors are essential to memory encoding, and encoding processes have been suggested to contribute to the success of memory retrieval, we investigate whether postacute anti-NMDA receptor encephalitis leads to abnormal brain activation during verbal memory encoding and its potential effects on subsequent memory retrieval performance. To address this issue, this study recruited 21 adult patients with anti-NMDA receptor encephalitis past the acute stage and 22 healthy controls (HCs). Functional magnetic resonance imaging (fMRI) data were collected when they completed an episodic memory task. At the neural level, the patients showed higher brain activation than the HCs in the bilateral hippocampus/parahippocampus (HG/PHG), right superior temporal gyrus (STG), and right thalamus during memory encoding. At the behavioral level, the patients showed worse memory retrieval performance than the HCs. Importantly, greater brain activation in the left HG/PHG during memory encoding was significantly associated with worse memory retrieval performance among the patients. Our findings indicate that postacute anti-NMDA receptor encephalitis is likely related to altered brain activation during memory encoding. Particularly, less memory retrieval performance often observed in patients with postacute anti-NMDA receptor encephalitis may result from abnormal activation in HG during encoding. These observations may enhance our understanding of NMDA receptor dysfunction in the human brain. Impact statement Patients with anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis are often left with permanent memory impairments. In this study, brain activation during verbal memory encoding and its potential effects on subsequent memory retrieval performance are addressed using 21 adult patients with postacute anti-NMDA receptor encephalitis and 22 healthy controls. Greater brain activation in the left hippocampus/parahippocampus during memory encoding was significantly associated with worse memory retrieval performance among the patients. These observations enhance our understanding of NMDA receptor dysfunction in the human brain.
抗 N-甲基-D-天冬氨酸（anti-NMDA）受体脑炎患者常伴有永久性记忆障碍。鉴于 NMDA 受体对记忆编码至关重要，并且编码过程被认为有助于记忆检索的成功，我们研究了急性后抗 NMDA 受体脑炎是否会导致言语记忆编码期间大脑激活异常及其对随后记忆检索性能的潜在影响。为了解决这个问题，本研究招募了 21 名急性后抗 NMDA 受体脑炎成年患者和 22 名健康对照者（HCs）。当他们完成情节记忆任务时，采集了功能磁共振成像（fMRI）数据。在神经水平上，与 HCs 相比，患者在记忆编码期间双侧海马/旁海马区（HG/PHG）、右侧颞上回（STG）和右侧丘脑的大脑激活更高。在行为水平上，患者的记忆检索表现比 HCs 差。重要的是，记忆编码期间左 HG/PHG 的大脑激活越大，患者的记忆检索表现越差。我们的研究结果表明，急性后抗 NMDA 受体脑炎可能与记忆编码期间大脑激活改变有关。特别是，急性后抗 NMDA 受体脑炎患者中经常观察到的记忆检索表现较差可能是由于编码过程中 HG 的异常激活所致。这些观察结果可能增强我们对人类大脑中 NMDA 受体功能障碍的理解。
