Role of a striatal slowly inactivating potassium current in short-term facilitation of corticostriatal inputs: A computer simulation study

Striatal output neurons (SONs) integrate glutamatergic synaptic inputs orig inating from the cerebral cortex. In vivo electrophysiological data have sh own that a prior depolarization of SONs induced a short-term (II sec) incre ase in their membrane excitability, which facilitated the ability of cortic ostriatal synaptic potentials to induce firing. Here we propose, using a co mputational model of SONs, that the use-dependent, short-term increase in t he responsiveness of SONs mainly results from the slow kinetics of a voltag e-dependent, slowly inactivating potassium A-current. This mechanism confer s on SONs a form of intrinsic short-term memory that optimizes the synaptic input-output relationship as a function of their past activation.