Lei Tianhao, Scheid Michael R, Glaser Joshua I, Slutzky Marc W
Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Department of Computer Science, Northwestern University, Evanston, IL 60201, USA.
bioRxiv. 2025 Jul 11:2025.07.10.663559. doi: 10.1101/2025.07.10.663559.
Cortical high gamma activity (HGA) is used in many scientific investigations, yet its biophysical source is a matter of debate. Two leading hypotheses are that HGA predominantly represents summed postsynaptic potentials or-more commonly- predominantly represents summed local spikes. If the latter were true, the nearest neurons to an electrode should contribute most to HGA recorded on that electrode. We trained subjects to decouple spiking from HGA on a single electrode using a brain-machine interface. Their ability to decouple them indicated that HGA is not primarily generated by summed local spiking. Instead, HGA correlated with neuronal population co-firing of neurons that were widely distributed across millimeters. The neuronal spikes that contributed more to this co-firing also contributed more to, and preceded, spike-triggered HGA. These results suggest that HGA arises predominantly from summed postsynaptic potentials triggered by synchronous co-firing of widely distributed neurons.
皮质高伽马活动（HGA）在许多科学研究中都有应用，但其生物物理来源仍是一个有争议的问题。两个主要假说是，HGA主要代表总和的突触后电位，或者更常见的是，主要代表总和的局部尖峰。如果后者是真的，那么离电极最近的神经元应该对该电极记录的HGA贡献最大。我们训练受试者使用脑机接口将单个电极上的尖峰与HGA解耦。他们解耦的能力表明，HGA并非主要由总和的局部尖峰产生。相反，HGA与广泛分布在毫米范围内的神经元群体共同放电相关。对这种共同放电贡献更大的神经元尖峰，对尖峰触发的HGA贡献也更大，并且先于尖峰触发的HGA。这些结果表明，HGA主要来自广泛分布的神经元同步共同放电触发的总和突触后电位。
