CENTRAL AUDITORY-SYSTEM PLASTICITY - GENERALIZATION TO NOVEL STIMULI FOLLOWING LISTENING TRAINING

Behavioral perceptual abilities and neurophysiologic changes observed after listening training can generalize to other stimuli not used in t he training paradigm, thereby demonstrating behavioral ''transfer of l earning'' and plasticity in underlying physiologic processes. Nine nor mal-hearing monolingual English-speaking adults were trained to identi fy a prevoiced labial stop sound (one that is not used phonemically in the English language). After training, the subjects were asked to dis criminate and identify a prevoiced alveolar stop. Mismatch negativity cortical evoked responses (MMN) were recorded to both labial and alveo lar stimuli before and after training, Behavioral performance and MMNs also were evaluated in an age-matched control group that did not rece ive training, Listening training improved the experimental group's abi lity to discriminate and identify an unfamiliar VOT contrast. That enh anced ability transferred from one place of articulation (labial) to a nother (alveolar). The behavioral training effects were reflected in t he MMN, which showed an increase in duration and area when elicited by the training stimuli as well as a decrease in onset latency when elic ited by the transfer stimuli. Interestingly, changes in the MMN were l argest over tile left hemisphere. The results demonstrate that trainin g can generalize to listening situations beyond those used in training sessions, and that the preattentive central neurophysiology underlyin g perceptual learning an altered through auditory training, (C) 1997 A coustical Society of America. [S0001-4966(97)00912-0].