Brett B, Krishnan G, Barth D S
Department of Psychology, University of Colorado, Boulder 80309-0345, USA.
Brain Res. 1996 May 20;721(1-2):155-66. doi: 10.1016/0006-8993(96)00168-0.
Functional subdivisions of auditory cortex in the rat were identified based on the distribution of temporal components of the mid-latency auditory evoked potential (MAEP) recorded with a multichannel epipial electrode array. Spontaneous data collected from the same location exhibited spindle-shaped bursts of oscillations in the gamma-band (20-40 Hz) whose location and spatial distribution were similar to that of the MAEP complex in that the bursts were localized to primary and secondary auditory cortex, the principle targets of thalamocortical projections. This suggested that the neural generators of these electrophysiological events may be similar. However, ablation of the medial geniculate nucleus (MG) of the thalamus revealed that while this nucleus is required for the generation of MAEPs, it is not required for the generation of spontaneous gamma-band oscillations. Ablation of subcortical cholinergic nuclei revealed that cholinergic input via the thalamus or the basal forebrain is not necessary for the generation of either MAEPs or spontaneous gamma-band oscillations recorded in this study. These results indicated that there may be networks of cells in sensory cortical areas endowed with an intrinsic capacity to oscillate independently of sensory or cholinergic input, but that may be modulated by this input.
基于用多通道软脑膜电极阵列记录的中潜伏期听觉诱发电位（MAEP）的时间成分分布，确定了大鼠听觉皮层的功能分区。从同一位置收集的自发数据显示，在γ波段（20 - 40Hz）出现纺锤形振荡爆发，其位置和空间分布与MAEP复合体相似，因为这些爆发局限于初级和次级听觉皮层，即丘脑皮质投射的主要目标区域。这表明这些电生理事件的神经发生器可能相似。然而，丘脑内侧膝状体（MG）的损毁显示，虽然该核是产生MAEP所必需的，但不是产生自发γ波段振荡所必需的。皮层下胆碱能核的损毁显示，通过丘脑或基底前脑的胆碱能输入对于本研究中记录的MAEP或自发γ波段振荡的产生并非必要。这些结果表明，感觉皮层区域可能存在细胞网络，它们具有独立于感觉或胆碱能输入而振荡的内在能力，但可能会受到这种输入的调节。
