Center for Neural Science, New York University, New York, NY 10003, USA.
Proc Natl Acad Sci U S A. 2012 Aug 21;109(34):13871-6. doi: 10.1073/pnas.1201478109. Epub 2012 Aug 7.
Studying the laminar pattern of neural activity is crucial for understanding the processing of neural signals in the cerebral cortex. We measured neural population activity [multiunit spike activity (MUA) and local field potential, LFP] in Macaque primary visual cortex (V1) in response to drifting grating stimuli. Sustained visually driven MUA was at an approximately constant level across cortical depth in V1. However, sustained, visually driven, local field potential power, which was concentrated in the γ-band (20-60 Hz), was greatest at the cortical depth corresponding to cortico-cortical output layers 2, 3, and 4B. γ-band power also tends to be more sustained in the output layers. Overall, cortico-cortical output layers accounted for 67% of total γ-band activity in V1, whereas 56% of total spikes evoked by drifting gratings were from layers 2, 3, and 4B. The high-resolution layer specificity of γ-band power, the laminar distribution of MUA and γ-band activity, and their dynamics imply that neural activity in V1 is generated by laminar-specific mechanisms. In particular, visual responses of MUA and γ-band activity in cortico-cortical output layers 2, 3, and 4B seem to be strongly influenced by laminar-specific recurrent circuitry and/or feedback.
研究神经活动的层模式对于理解大脑皮层中神经信号的处理至关重要。我们测量了猕猴初级视觉皮层（V1）中对漂移光栅刺激的神经群体活动（多单位尖峰活动（MUA）和局部场电位，LFP）。在 V1 中，持续的视觉驱动 MUA 在皮层深度上大致保持恒定水平。然而，持续的、视觉驱动的、局部场电位功率集中在γ带（20-60 Hz），在对应于皮质-皮质输出层 2、3 和 4B 的皮层深度处最大。γ带功率也倾向于在输出层中更持续。总体而言，皮质-皮质输出层占 V1 中总γ带活动的 67%，而由漂移光栅诱发的总尖峰的 56%来自 2、3 和 4B 层。γ带功率的高分辨率层特异性、MUA 和 γ带活动的层分布及其动力学表明，V1 中的神经活动是由层特异性机制产生的。特别是，皮质-皮质输出层 2、3 和 4B 中的 MUA 和 γ带活动的视觉反应似乎受到层特异性递归电路和/或反馈的强烈影响。
