ASSOCIATIVE PAIRING OF TACTILE STIMULATION INDUCES SOMATOSENSORY CORTICAL REORGANIZATION IN RATS AND HUMANS

WE used a protocol of associative (Hebbian) pairing of tactile stimula tion (APTS) to evoke cortical plastic changes. Reversible reorganizati on of the adult rat paw representations in somatosensory cortex (SI) i nduced by a few hours of APTS included selective enlargement of the ar eas of cortical neurones representing the stimulated skin fields and o f the corresponding receptive fields (RFs). Late, presumably NMDA rece ptor-mediated response components were enhanced, indicating an involve ment of glutamatergic synapses. A control protocol of identical stimul us pattern applied to only a single skin site revealed no changes of R Fs, indicating that co-activation is crucial for induction. Using an a nalogous APTS protocol in humans revealed an increase of spatial discr imination performance indicating that fast plastic processes based on co-activation patterns act on a cortical and perceptual level.