Persistent and specific influences of early acoustic environments on primary auditory cortex

This study demonstrates that the adult form of 'tonotopic maps' of sound fr equency in the rat primary auditory cortex (A1) arises from parallel develo pmental processes involving two cortical zones: the progressive differentia tion and refinement of selectively tone-responsive receptive fields within an initially broadly-tuned posterior zone, and the progressive loss of tone -evoked, short-latency response over an initially large, very broadly tuned anterior zone. The formation of tonotopic maps in A1 was specifically infl uenced by a rat pup's early acoustic environments. Exposure to pulsed tones resulted in accelerated emergence and an expansion of A1 representations o f those specific tone frequencies, as well as a deteriorated tonotopicity a nd broader-than-normal receptive fields. Thus, auditory experiences during early postnatal development are important in shaping the functional develop ment of auditory cortical representations of specific acoustic environments .