Alternative Medicine Research Today is a free monthly online journal that collates and summarizes the latest research about Alternative Medicine, including details on complementary medicine, alternative therapies, homeopathy.

Changes in auditory cortex parallel rapid perceptual learning.

Alain C, Snyder JS, He Y, Reinke KS

Rotman Research Institute, Baycrest Centre for Geriatric Care, Toronto M6A 2E1, Canada. calain@rotman-baycrest.on.ca

Learning perceptual skills is characterized by rapid improvements in performance within the first hour of training (fast perceptual learning) followed by more gradual improvements that take place over several daily practice sessions (slow perceptual learning). Although it is widely accepted that slow perceptual learning is accompanied by enhanced stimulus representation in sensory cortices, there is considerable controversy about the neural substrates underlying early and rapid improvements in learning perceptual skills. Here we measured event-related brain potentials while listeners were presented with 2 phonetically different vowels. Listeners' ability to identify both vowels improved gradually during the first hour of testing and was paralleled by enhancements in an early evoked response ( approximately 130 ms) localized in the right auditory cortex and a late evoked response ( approximately 340 ms) localized in the right anterior superior temporal gyrus and/or inferior prefrontal cortex. These neuroplastic changes depended on listeners' attention and were preserved only if practice was continued; familiarity with the task structure (procedural learning) was not sufficient. We propose that the early increases in cortical responsiveness reflect goal-directed changes in the tuning properties of auditory neurons involved in parsing concurrent speech signals. Importantly, the neuroplastic changes occurred rapidly, demonstrating the flexibility of human speech segregation mechanisms.

Published 5 April 2007 in Cereb Cortex, 17(5): 1074-84.
Full-text of this article is available online (may require subscription).

© 2005-2008 Alternative Medicine Research Today. All Rights Reserved.