Effects of short interval intracortical inhibition and intracortical facilitation on short interval intracortical facilitation in human primary motor cortex

摘要: Short interval intracortical facilitation (SICF) can be elicited by transcranial magnetic stimulation (TMS) of the motor cortex (M1) with a suprathreshold first stimulus (S1) followed subthreshold second (S2). SICF occurs at three distinct phases and is likely to related generation indirect (I) waves. inhibition (SICI) an inhibitory phenomenon (ICF) excitatory occurring in M1 that studied TMS. We interactions between SICI/ICF 17 healthy subjects. Six experiments were conducted. The experiment examined effects different S1 intensities on SICI, ICF peaks. SICI tested triple-pulse TMS protocol experiment. performed Experiments 3–5 further test various strengths peaks troughs, generated current direction which preferentially generates late I Experiment 6. results showed decreased whereas increased higher intensities. facilitated mediated waves both troughs SICF. increase presence correlated strength SICI. third peak conclude facilitates neuronal circuits responsible for generating through disinhibition, while may have opposite effects.