REVERSIBLE RELOCATION OF REPRESENTATIONAL BOUNDARIES OF ADULT-RATS BYINTRACORTICAL MICROSTIMULATION

CORTICAL reorganization of somatosensory maps of adult rats is not res tricted to central, already cutaneous zones. A few hours of intracorti cal microstimulation (ICMS) at the boundaries of the hindpaw represent ation generated plastic reorganization beyond these functionally defin ed representational borders by inducing new skin field representations in previously non-somatic cortical regions, from where low-threshold movements could be elicited. In this way, individually defined borders could be reversibly relocated over distances up to 800 microns, conta ining selectively skin field representations of the ICMS site. Respons e amplitude and latency characteristics of these newly induced cutaneo us recordings sites resembled those recorded under control in the cent ral representational zones. The results suggest that ICMS-induced plas ticity acts across areal and modality borders by fast modulation of sy napses in overlapping cortical and subcortical networks.