Temporal plasticity in the primary auditory cortex induced by operant perceptual learning.

Processing of rapidly successive acoustic stimuli can be markedly improved by sensory training. To investigate the cortical mechanisms underlying such temporal plasticity, we trained rats in a 'sound maze' in which navigation using only auditory cues led to a target location paired with food reward. In this task, the repetition rate of noise pulses increased as the distance between the rat and target location decreased. After training in the sound maze, neurons in the primary auditory cortex (A1) showed greater responses to high-rate noise pulses and stronger phase-locking of responses to the stimuli; they also showed shorter post-stimulation suppression and stronger rebound activation. These improved temporal dynamics transferred to trains of pure-tone pips. Control animals that received identical sound stimulation but were given free access to food showed the same results as naive rats. We conclude that this auditory perceptual learning results in improvements in temporal processing, which may be mediated by enhanced cortical response dynamics.