Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720.
Department of Physics, University of California-Berkeley, Berkeley, California 94720.
J Neurosci. 2022 May 4;42(18):3733-3748. doi: 10.1523/JNEUROSCI.1787-21.2022. Epub 2022 Mar 24.
Electrocorticography (ECoG) methodologically bridges basic neuroscience and understanding of human brains in health and disease. However, the localization of ECoG signals across the surface of the brain and the spatial distribution of their generating neuronal sources are poorly understood. To address this gap, we recorded from rat auditory cortex using customized μECoG, and simulated cortical surface electrical potentials with a full-scale, biophysically detailed cortical column model. Experimentally, μECoG-derived auditory representations were tonotopically organized and signals were anisotropically localized to less than or equal to ±200 μm, that is, a single cortical column. Biophysical simulations reproduce experimental findings and indicate that neurons in cortical layers V and VI contribute ∼85% of evoked high-gamma signal recorded at the surface. Cell number and synchrony were the primary biophysical properties determining laminar contributions to evoked μECoG signals, whereas distance was only a minimal factor. Thus, evoked μECoG signals primarily originate from neurons in the infragranular layers of a single cortical column. ECoG methodologically bridges basic neuroscience and understanding of human brains in health and disease. However, the localization of ECoG signals across the surface of the brain and the spatial distribution of their generating neuronal sources are poorly understood. We investigated the localization and origins of sensory-evoked ECoG responses. We experimentally found that ECoG responses were anisotropically localized to a cortical column. Biophysically detailed simulations revealed that neurons in layers V and VI were the primary sources of evoked ECoG responses. These results indicate that evoked ECoG high-gamma responses are primarily generated by the population spike rate of pyramidal neurons in layers V and VI of single cortical columns and highlight the possibility of understanding how microscopic sources produce mesoscale signals.
脑电描记术 (ECoG) 在基础神经科学和理解健康与疾病人类大脑方面架起了桥梁。然而，大脑表面的 ECoG 信号的定位及其产生神经元源的空间分布尚不清楚。为了解决这一差距，我们使用定制的 μECoG 记录大鼠听觉皮层，并使用全尺度、生物物理细节丰富的皮质柱模型模拟皮质表面的电场电位。在实验中，μECoG 衍生的听觉代表是音位组织的，信号在小于或等于±200 μm 的范围内呈各向异性定位，即单个皮质柱。生物物理模拟再现了实验结果，并表明皮质层 V 和 VI 中的神经元对记录在表面的诱发高γ信号贡献了约 85%。细胞数量和同步性是决定皮层柱对诱发 μECoG 信号的分层贡献的主要生物物理特性，而距离仅是一个最小因素。因此，诱发的 μECoG 信号主要来源于单个皮质柱的下颗粒层中的神经元。ECoG 在基础神经科学和理解健康与疾病人类大脑方面架起了桥梁。然而，大脑表面的 ECoG 信号的定位及其产生神经元源的空间分布尚不清楚。我们研究了感觉诱发 ECoG 反应的定位和起源。我们在实验中发现 ECoG 反应呈各向异性地定位在一个皮质柱上。生物物理细节模拟揭示了 V 层和 VI 层中的神经元是诱发 ECoG 反应的主要来源。这些结果表明，诱发的 ECoG 高γ反应主要是由单个皮质柱的 V 和 VI 层中的锥体神经元的群体峰电位率产生的，这突出了理解微观来源如何产生中尺度信号的可能性。
