Picazio Silvia, Veniero Domenica, Ponzo Viviana, Caltagirone Carlo, Gross Joachim, Thut Gregor, Koch Giacomo
Non-Invasive Brain Stimulation Unit, Clinical and Behavioral Neurology Department, IRCCS Santa Lucia Foundation, Rome 00179, Italy.
Non-Invasive Brain Stimulation Unit, Clinical and Behavioral Neurology Department, IRCCS Santa Lucia Foundation, Rome 00179, Italy; Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QB, UK.
Curr Biol. 2014 Dec 15;24(24):2940-5. doi: 10.1016/j.cub.2014.10.043. Epub 2014 Dec 4.
A fully adapted behavior requires maximum efficiency to inhibit processes in the motor domain. Although a number of cortical and subcortical brain regions have been implicated, converging evidence suggests that activation of right inferior frontal gyrus (r-IFG) and right presupplementary motor area (r-preSMA) is crucial for successful response inhibition. However, it is still unknown how these prefrontal areas convey the necessary signal to the primary motor cortex (M1), the cortical site where the final motor plan eventually has to be inhibited or executed. On the basis of the widely accepted view that brain oscillations are fundamental for communication between neuronal network elements, one would predict that the transmission of these inhibitory signals within the prefrontal-central networks (i.e., r-IFG/M1 and/or r-preSMA/M1) is realized in rapid, periodic bursts coinciding with oscillatory brain activity at a distinct frequency. However, the dynamics of corticocortical effective connectivity has never been directly tested on such timescales. By using double-coil transcranial magnetic stimulation (TMS) and electroencephalography (EEG), we assessed instantaneous prefrontal-to-motor cortex connectivity in a Go/NoGo paradigm as a function of delay from (Go/NoGo) cue onset. In NoGo trials only, the effects of a conditioning prefrontal TMS pulse on motor cortex excitability cycled at beta frequency, coinciding with a frontocentral beta signature in EEG. This establishes, for the first time, a tight link between effective cortical connectivity and related cortical oscillatory activity, leading to the conclusion that endogenous (top-down) inhibitory motor signals are transmitted in beta bursts in large-scale cortical networks for inhibitory motor control.
一种完全适应的行为需要最大效率来抑制运动领域的过程。尽管许多皮质和皮质下脑区都与之相关，但越来越多的证据表明，右侧额下回（r-IFG）和右侧辅助运动前区（r-preSMA）的激活对于成功的反应抑制至关重要。然而，这些前额叶区域如何将必要的信号传递到初级运动皮层（M1），即最终必须抑制或执行最终运动计划的皮质部位，仍然未知。基于脑振荡是神经元网络元件之间通信的基础这一广泛接受的观点，可以预测这些抑制性信号在前额叶-中央网络（即r-IFG/M1和/或r-preSMA/M1）内的传递是在与特定频率的脑振荡活动一致的快速、周期性爆发中实现的。然而，皮质-皮质有效连接的动力学从未在这样的时间尺度上直接进行过测试。通过使用双线圈经颅磁刺激（TMS）和脑电图（EEG），我们在Go/NoGo范式中评估了从（Go/NoGo）提示开始延迟的函数下，前额叶到运动皮层的瞬时连接性。仅在NoGo试验中，条件性前额叶TMS脉冲对运动皮层兴奋性的影响以β频率循环，这与脑电图中的额中央β特征一致。这首次建立了有效皮质连接与相关皮质振荡活动之间的紧密联系，得出内源性（自上而下）抑制性运动信号在大规模皮质网络中以β爆发形式传递用于抑制性运动控制的结论。
