Effects of Lithium on Plasticity in Human Motor Cortex Induced by Paired Associative Stimulation

Background: Lithium is widely used for the treatment of bipolar disorders. Relatively little is known about the CNS actions of lithium. One mode of action is that lithium inhibits the GSK–3ß kinase, an enzyme that in rat hippocampal slices mediates an interaction between two major forms of synaptic plasticity, i.e. long-term potentiation (LTP) and long-term depression (LTD). Inhibition of GSK–3ß favors LTP over LTD. Here we sought to examine the effects of a single oral dose of 900mg of lithium on LTP-like and LTD-like plasticity in human motor cortex, using established paired associative stimulation (PAS-LTP an…