COMPENSATORY PLASTICITY FOLLOWING NEONATAL LESION OF THE AUDITORY-CORTEX

It has been previously reported that bilateral damage in the auditory cortex resulted in a severe deficit in the acquisition of the auditory pattern discrimination if the lesion was incurred at adulthood while animals with comparable lesion on the day of birth could learn the dis crimination. This article surveys the possible mechanisms of the plast icity underlying the sparing of function following the neonatal lesion of the brain. In rats, temporal pattern recognition is processed in a specialized area, auditory belt area. Thus, it is plausible to consid er that a damaged cortical function is represented by an entirely new area that is not originally related to recognition of temporal pattern . Also a critical period for sparing of auditory pattern discriminatio n was assumed to be around weaning. By the time of weaning, although b asic auditory functions are completed, sensory association is not matu re. Thus, these findings imply that auditory pattern discrimination wa s spared from early brain damage if the brain is injured before integr ative function and circuitry of cortex are still under development. Fi nally, temporal pattern recognition is discussed as a fundamental of l anguage skills.