Middleton Steven, Jalics Jozsi, Kispersky Tilman, Lebeau Fiona E N, Roopun Anita K, Kopell Nancy J, Whittington Miles A, Cunningham Mark O
Institute of Neuroscience, Newcastle University, Newcastle NE2 4HH, United Kingdom.
Proc Natl Acad Sci U S A. 2008 Nov 25;105(47):18572-7. doi: 10.1073/pnas.0809302105. Epub 2008 Nov 7.
Local circuits in the medial entorhinal cortex (mEC) and hippocampus generate gamma frequency population rhythms independently. Temporal interaction between these areas at gamma frequencies is implicated in memory-a phenomenon linked to activity of NMDA-subtype glutamate receptors. While blockade of NMDA receptors does not affect frequency of gamma rhythms in hippocampus, it exposes a second, lower frequency (25-35 Hz) gamma rhythm in mEC. In experiment and model, NMDA receptor-dependent mEC gamma rhythms were mediated by basket interneurons, but NMDA receptor-independent gamma rhythms were mediated by a novel interneuron subtype-the goblet cell. This cell was distinct from basket cells in morphology, intrinsic membrane properties and synaptic inputs. The two different gamma frequencies matched the different intrinsic frequencies in hippocampal areas CA3 and CA1, suggesting that NMDA receptor activation may control the nature of temporal interactions between mEC and hippocampus, thus influencing the pathway for information transfer between the two regions.
内嗅皮质内侧（mEC）和海马体中的局部回路可独立产生γ频率的群体节律。这些区域在γ频率下的时间相互作用与记忆有关，而记忆是一种与NMDA亚型谷氨酸受体活性相关的现象。虽然阻断NMDA受体会影响海马体中γ节律的频率，但它会在mEC中暴露出第二种较低频率（25 - 35赫兹）的γ节律。在实验和模型中，依赖NMDA受体的mECγ节律由篮状中间神经元介导，但不依赖NMDA受体的γ节律由一种新型中间神经元亚型——杯状细胞介导。这种细胞在形态、内在膜特性和突触输入方面与篮状细胞不同。这两种不同的γ频率与海马体CA3区和CA1区不同的固有频率相匹配，这表明NMDA受体激活可能控制mEC和海马体之间时间相互作用的性质，从而影响这两个区域之间的信息传递途径。
