Unit on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health Bethesda, MD, USA.
Front Syst Neurosci. 2010 Aug 10;4. doi: 10.3389/fnsys.2010.00031. eCollection 2010.
Spatial patterns of spontaneous neural activity at rest have previously been associated with specific networks in the brain, including those pertaining to the functional architecture of the primary visual cortex (V1). However, despite the prominent anatomical differences between cortical layers, little is known about the laminar pattern of spontaneous activity in V1. We address this topic by investigating the amplitude and coherence of ongoing local field potential (LFP) signals measured from different layers in V1 of macaque monkeys during rest and upon presentation of a visual stimulus. We used a linear microelectrode array to measure LFP signals at multiple, evenly spaced positions throughout the cortical thickness. Analyzing both the mean LFP amplitudes and between-contact LFP coherences, we identified two distinct zones of activity, roughly corresponding to superficial and deep layers, divided by a sharp transition near the bottom of layer 4. The LFP signals within each laminar zone were highly coherent, whereas those between zones were not. This functional compartmentalization was found not only during rest, but also when the receptive field was stimulated during a visual task. These results demonstrate the existence of distinct superficial and deep functional domains of coherent LFP activity in V1 that may reflect the intrinsic interplay of V1 microcircuitry with cortical and subcortical targets, respectively.
静息状态下自发神经活动的空间模式先前与大脑中的特定网络有关,包括与初级视觉皮层(V1)的功能结构有关的网络。然而,尽管皮质层之间存在明显的解剖差异,但关于 V1 中自发活动的分层模式知之甚少。我们通过研究猕猴 V1 中不同层在静息和呈现视觉刺激时测量的局部场电位(LFP)信号的幅度和相干性来解决这个问题。我们使用线性微电极阵列在皮质厚度内的多个均匀间隔位置测量 LFP 信号。分析平均 LFP 幅度和接触间 LFP 相干性,我们确定了两个活动的明显区域,大致对应于浅层和深层,由 4 层底部附近的急剧转变分开。每个层区的 LFP 信号具有高度的相干性,而区之间的信号则没有。这种功能分隔不仅在静息时存在,而且在视觉任务中刺激感受野时也存在。这些结果表明 V1 中存在明显的浅层和深层功能域的相干 LFP 活动,这可能分别反映了 V1 微电路与皮质和皮质下靶标的内在相互作用。