Maier Alexander, Cox Michele A, Dougherty Kacie, Moore Brandon, Leopold David A
Department of Psychology, College of Arts and Science, Vanderbilt University, Nashville, TN, USA.
Section on Cognitive Neurophysiology and Imaging, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA.
Eye Brain. 2014 Sep 23;6(Suppl 1):113-120. doi: 10.2147/EB.S51822. eCollection 2014.
The mammalian neocortex features distinct anatomical variation in its tangential and radial extents. This review consolidates previously published findings from our group in order to compare and contrast the spatial profile of neural activity coherence across these distinct cortical dimensions. We focus on studies of ongoing local field potential (LFP) data obtained simultaneously from multiple sites in the primary visual cortex in two types of experiments in which electrode contacts were spaced either along the cortical surface or at different laminar positions. These studies demonstrate that across both dimensions the coherence of ongoing LFP fluctuations diminishes as a function of interelectrode distance, although the nature and spatial scale of this falloff is very different. Along the cortical surface, the overall LFP coherence declines gradually and continuously away from a given position. In contrast, across the cortical layers, LFP coherence is discontinuous and compartmentalized as a function of depth. Specifically, regions of high LFP coherence fall into discrete superficial and deep laminar zones, with an abrupt discontinuity between the granular and infragranular layers. This spatial pattern of ongoing LFP coherence is similar when animals are at rest and when they are engaged in a behavioral task. These results point to the existence of partially segregated laminar zones of cortical processing that extend tangentially within the laminar compartments and are thus oriented orthogonal to the cortical columns. We interpret these electrophysiological observations in light of the known anatomical organization of the cortical microcircuit.
哺乳动物新皮层在其切向和径向范围具有明显的解剖学差异。本综述整合了我们团队之前发表的研究结果，以便比较和对比在这些不同皮层维度上神经活动连贯性的空间分布。我们重点关注在两种类型的实验中从初级视觉皮层多个部位同时获取的持续局部场电位（LFP）数据的研究，在这些实验中，电极触点要么沿着皮层表面分布，要么处于不同的层位。这些研究表明，在这两个维度上，持续LFP波动的连贯性都随着电极间距离的增加而减弱，尽管这种衰减的性质和空间尺度有很大不同。沿着皮层表面，整体LFP连贯性从给定位置逐渐且持续下降。相比之下，在皮层各层之间，LFP连贯性作为深度的函数是不连续且分隔的。具体而言，高LFP连贯性区域分为离散的浅层和深层区域，在颗粒层和颗粒下层之间存在突然的不连续性。当动物处于休息状态和进行行为任务时，这种持续LFP连贯性的空间模式是相似的。这些结果表明存在部分分离的皮层处理层状区域，这些区域在层状隔室内切向延伸，因此与皮层柱正交。我们根据已知的皮层微电路解剖组织来解释这些电生理观察结果。
