Wellcome Centre for Integrative Neuroimaging, Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom;
Centre for Brain Science, Department of Psychology, University of Essex, Colchester CO4 3SQ, United Kingdom.
Proc Natl Acad Sci U S A. 2021 Sep 14;118(37). doi: 10.1073/pnas.2100652118.
The origins of oscillatory activity in the brain are currently debated, but common to many hypotheses is the notion that they reflect interactions between brain areas. Here, we examine this possibility by manipulating the strength of coupling between two human brain regions, ventral premotor cortex (PMv) and primary motor cortex (M1), and examine the impact on oscillatory activity in the motor system measurable in the electroencephalogram. We either increased or decreased the strength of coupling while holding the impact on each component area in the pathway constant. This was achieved by stimulating PMv and M1 with paired pulses of transcranial magnetic stimulation using two different patterns, only one of which increases the influence exerted by PMv over M1. While the stimulation protocols differed in their temporal patterning, they were comprised of identical numbers of pulses to M1 and PMv. We measured the impact on activity in alpha, beta, and theta bands during a motor task in which participants either made a preprepared action (Go) or withheld it (No-Go). Augmenting cortical connectivity between PMv and M1, by evoking synchronous pre- and postsynaptic activity in the PMv-M1 pathway, enhanced oscillatory beta and theta rhythms in Go and No-Go trials, respectively. Little change was observed in the alpha rhythm. By contrast, diminishing the influence of PMv over M1 decreased oscillatory beta and theta rhythms in Go and No-Go trials, respectively. This suggests that corticocortical communication frequencies in the PMv-M1 pathway can be manipulated following Hebbian spike-timing-dependent plasticity.
大脑中震荡活动的起源目前仍存在争议，但许多假说都认为它们反映了大脑区域之间的相互作用。在这里，我们通过操纵两个人类大脑区域腹侧运动前皮层 (PMv) 和初级运动皮层 (M1) 之间的耦合强度来检验这种可能性，并研究这种方法对脑电图中可测量的运动系统中震荡活动的影响。我们通过使用两种不同的模式来增加或减少耦合强度，同时保持通路上每个区域的影响不变。一种模式仅增强了 PMv 对 M1 的影响。虽然刺激方案在时间模式上有所不同，但它们都包含相同数量的脉冲刺激 M1 和 PMv。我们在一项运动任务中测量了在刺激方案下，参与者执行或抑制预先准备的动作（Go）时，alpha、beta 和 theta 波段活动的影响。通过在 PMv-M1 通路上引发同步的前突触和后突触活动，增强了 PMv 和 M1 之间的皮质连接，分别增强了 Go 和 No-Go 试验中的震荡 beta 和 theta 节律。在 alpha 节律中几乎没有观察到变化。相反，降低 PMv 对 M1 的影响分别降低了 Go 和 No-Go 试验中的震荡 beta 和 theta 节律。这表明 PMv-M1 通路中的皮质间通讯频率可以根据赫布氏尖峰时间依赖可塑性进行操纵。
