Long-term and Time Dependent Homeostatic and Non-Homeostatic Metaplasticity in Human Motor Cortex

Aims: Studies in human primary motor cortex (M1) provided evidence for homeostatic as well as non-homeostatic forms of metaplasticity, but the conditions favoring one principle over the other are not well understood yet. Here we studied the role of time between two consecutive long-term potentiation (LTP)-like plasticity processes in human M1 on the expression of metaplasticity. Methods: 27 healthy subjects participated in the study. Paired associative stimulation (PAS) was used to induce LTP-like plasticity in M1 (Müller-Dahlhaus et al. [2010] Front Synaptic Neurosci 2: 34). Motor cortical plasticity was indexe…