INSERM U1028, UMR5292, UCBL, Lyon Neuroscience Research Center, Neurocampus, 95 boulevard Pinel, Bron 69500, France.
CNRS, Integrative Neuroscience and Cognition Center, Université Paris Cité, 45, rue des Saints-Pères, Paris F-75006, France.
Cereb Cortex. 2023 Jun 20;33(13):8286-8299. doi: 10.1093/cercor/bhad114.
Neocortical interneurons provide inhibition responsible for organizing neuronal activity into brain oscillations that subserve cognitive functions such as memory, attention, or prediction. However, the interneuronal contribution to the entrainment of neocortical oscillations within and across different cortical layers was not described. Here, using layer-specific optogenetic stimulations with micro-Light-Emitting Diode arrays, directed toward parvalbumin-expressing (PV) interneurons in non-anesthetized awake mice, we found that supragranular layer stimulations of PV neurons were most efficient at entraining supragranular local field potential (LFP) oscillations at gamma frequencies (γ: 25-80 Hz), whereas infragranular layer stimulation of PV neurons better entrained the LFP at delta (δ: 2-5 Hz) and theta (θ: 6-10 Hz) frequencies. At the level of neuronal action potential activity, we observed that supragranular neurons better followed the imposed PV stimulation rhythm than their infragranular counterparts at most frequencies when the stimulation was delivered in their respective layer. Moreover, the neuronal entrainment evoked by local stimulation could propagate across layers, though with a lesser impact when the stimulation occurs in deep layers, suggesting a direction-specific laminar propagation. These results establish a layer-based framework for oscillations to entrain the primary somatosensory cortex in awake conditions.
新皮层中间神经元提供抑制作用，负责将神经元活动组织成脑振荡，从而支持认知功能，如记忆、注意力或预测。然而，中间神经元对新皮层振荡的同步化的贡献，无论是在不同皮层层内还是跨皮层层，都没有被描述。在这里，我们使用带有微发光二极管阵列的层特异性光遗传学刺激，针对非麻醉清醒小鼠中表达 Parvalbumin 的中间神经元（PV 神经元），发现超颗粒层的 PV 神经元刺激最有效地同步超颗粒层局部场电位（LFP）在 γ 频段（γ：25-80 Hz）的振荡，而颗粒下层的 PV 神经元刺激则更好地同步 δ（δ：2-5 Hz）和 θ（θ：6-10 Hz）频段的 LFP。在神经元动作电位活动水平上，我们观察到，在大多数频率下，当刺激在各自的层中施加时，超颗粒层神经元比其颗粒下层神经元更能跟随施加的 PV 刺激节律。此外，局部刺激引起的神经元同步化可以在皮层层之间传播，但当刺激发生在深层时，影响较小，这表明存在具有方向性的皮层层间传播。这些结果为在清醒状态下同步初级体感皮层的振荡建立了一个基于皮层层的框架。
