Sensitive period for sensorimotor integration during vocal motor learning

Sensory experience during sensitive periods in development may direct the o rganization of neural substrates, thereby permanently influencing subsequen t adult behavior. We report a sensitive period during the imitative motor l earning phase of sensorimotor integration in birdsong development. By tempo rarily and reversibly blocking efference to the vocal muscles, we disrupted vocal motor practice during selected stages of song development. Motor dis ruption during prolonged periods early in development, which allows recover y of vocal control prior to the onset of adult song, has no effect on adult song production. However, song disruption late in development, during the emergence of adult song, results in permanent motor defects in adult song p roduction. These results reveal a decreased ability to compensate for inter ference with motor function when disturbances occur during the terminal sta ge of vocal motor development. Temporary disruption of syringeal motor cont rol in adults does not produce permanent changes in song production. Perman ent vocal aberrations in juveniles are evident exclusively in learned song elements rather than nonlearned calls, suggesting that the sensitive period is associated with motor learning. (C) 2000 John Wiley & Sons, Inc.