Barth D S, MacDonald K D
Department of Psychology, University of Colorado, Boulder 80309-345, USA.
Nature. 1996 Sep 5;383(6595):78-81. doi: 10.1038/383078a0.
Perhaps the most widely recognized but least understood electrophysiological activity of the cerebral cortex is its characteristic electrical oscillations. Recently, there have been efforts to understand the mechanisms underlying high-frequency gamma oscillations(approximately 40 Hz) because they may coordinate sensory processing between populations of cortical cells. High-resolution cortical recordings show the gamma oscillations are constrained to sensory cortex, that they occur independently in auditory and somatosensory cortex, and that they are phase-locked between primary and secondary sensory cortex. As yet, the mechanism of their neurogenesis is unknown. Whereas cortical neurons can produce gamma oscillations without subcortical input, they may also be modulated by the thalamus and basal forebrain. Here we report that the neural generator of gamma oscillations in auditory cortex seems to be intracortical, serving to synchronize interactions between the primary and secondary areas. The acoustic thalamus directly modulates these oscillations, which are inhibited by stimulation of the dorsal and ventral divisions of the medial geniculate nucleus (MGd and MGv) and evoked by stimulation of the adjacent posterior intralaminar nucleus (PIL).
或许大脑皮层最广为人知却又最不为人所理解的电生理活动就是其特有的电振荡。最近，人们一直在努力理解高频伽马振荡（约40赫兹）背后的机制，因为它们可能协调皮层细胞群之间的感觉处理。高分辨率皮层记录显示，伽马振荡局限于感觉皮层，在听觉和体感皮层中独立发生，并且在初级和次级感觉皮层之间是锁相的。迄今为止，它们的神经发生机制尚不清楚。虽然皮层神经元可以在没有皮层下输入的情况下产生伽马振荡，但它们也可能受到丘脑和基底前脑的调节。在此我们报告，听觉皮层中伽马振荡的神经发生器似乎位于皮层内，用于同步初级和次级区域之间的相互作用。听觉丘脑直接调节这些振荡，内侧膝状体核的背侧和腹侧部分（MGd和MGv）的刺激会抑制这些振荡，而相邻的后内侧层核（PIL）的刺激则会诱发这些振荡。
