Johnen Vanessa M, Neubert Franz-Xaver, Buch Ethan R, Verhagen Lennart, O'Reilly Jill X, Mars Rogier B, Rushworth Matthew F S
Department of Experimental Psychology, Oxford University, Oxford, United Kingdom.
Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States.
Elife. 2015 Feb 9;4:e04585. doi: 10.7554/eLife.04585.
Correlations in brain activity between two areas (functional connectivity) have been shown to relate to their underlying structural connections. We examine the possibility that functional connectivity also reflects short-term changes in synaptic efficacy. We demonstrate that paired transcranial magnetic stimulation (TMS) near ventral premotor cortex (PMv) and primary motor cortex (M1) with a short 8-ms inter-pulse interval evoking synchronous pre- and post-synaptic activity and which strengthens interregional connectivity between the two areas in a pattern consistent with Hebbian plasticity, leads to increased functional connectivity between PMv and M1 as measured with functional magnetic resonance imaging (fMRI). Moreover, we show that strengthening connectivity between these nodes has effects on a wider network of areas, such as decreasing coupling in a parallel motor programming stream. A control experiment revealed that identical TMS pulses at identical frequencies caused no change in fMRI-measured functional connectivity when the inter-pulse-interval was too long for Hebbian-like plasticity.
两个脑区之间的大脑活动相关性（功能连接性）已被证明与它们潜在的结构连接有关。我们研究了功能连接性也反映突触效能短期变化的可能性。我们证明，在腹侧运动前皮层（PMv）和初级运动皮层（M1）附近进行配对经颅磁刺激（TMS），脉冲间隔为8毫秒的短间隔，可诱发突触前和突触后同步活动，并以符合赫布可塑性的模式增强两个区域之间的区域间连接性，这会导致通过功能磁共振成像（fMRI）测量的PMv和M1之间的功能连接性增加。此外，我们表明，加强这些节点之间的连接性会对更广泛的区域网络产生影响，例如减少并行运动编程流中的耦合。一项对照实验表明，当脉冲间隔过长而无法产生类赫布可塑性时，相同频率的相同TMS脉冲不会导致fMRI测量的功能连接性发生变化。
