[The plastic reorganization of the neuronal receptive fields of the auditory cortex and medial geniculate body evoked by microstimulation of the auditory cortex].

The effects of intracortical microstimulation (ICMS) on receptive fields (RFs) of simultaneously recorded auditory cortex (A1) and medial geniculate body (MGB) neurons were examined in rats under ketamine. Three types of neurons were distinguished according to the configuration of their RFs: mono-, be-, and polymodal. It was shown that RFs of adjacent neurons may be different and Rfs of distant (up to 1 mm in rostro-caudal direction) neurons may be similar. ICMS was able to produce changes in RF structure of A1 neurons at and near the stimulation side and also in homotopically related regions of MGB. RFs of homotopically related A1 and MGB neurons mostly changed in a similar way after ICMS. We suggest that the mechanism underlying the observed RF changes of A1 and MGB neurons in related to ICMS-induced long-term changes (LTP and LTD) in synaptic efficacy of the cortex-thalamus-cortex loop.