Chapter 2 - Brain Plasticity and Perceptual Learning

Abstract

The brain—young as well as adult—has the capacity to change in response to changes in the external environment, to changes in the sensory input due to peripheral injury such as hearing loss, and as a result of training. Both adult and critical period animals show plastic changes in auditory cortex following passive exposure to tonal or noise stimuli. Changes in a response to a stimulus that does not involve associating the presented stimulus with another stimulus or event such as reward or punishment occur via habituation and sensitization. Perceptual learning, defined as practice-induced (training) improvement in the ability to perform specific perceptual tasks, has traditionally been portrayed as a bottom–up phenomenon that improves encoding or decoding of the trained stimulus by inducing changes in those processes that act as bottlenecks to performance. We also discuss the Reverse Hierarchy Theory that asserts that learning is a top–down guided process, which begins at high-level cortical areas of the sensory system. Auditory training alters the neural activity that codes for speech-sound learning. Its use in improving speech understanding in cochlear implant users is described, together with the specific problems of auditory training in children. Music training and video gaming could be new tools that might be used in training certain aspects of hearing in noisy environments, enhanced use of hearing aids and cochlear implants.