[Synaptic plasticity and neuromodulation of local cortical connections]

Long-term potentiation (LTP) and long-term depression (LTD) represent two forms of synaptic plasticity which may act as mechanisms for reorganizations of adult mammalian motor cortex. Layer II/III horizontal connections may form a substrate for these reorganizations. The induction of LTP in these connections requires conjoint activation of cortical layer V or layer I. The activity of the cholinergic system facilitates LTP induction.