Visual Cortical Plasticity and Perceptual Learning

Abstract

Plasticity is an integral property of a functioning brain throughout life. In the visual system, cortical plasticity is engaged for encoding the geometric regularities of the visual environment early in life, as well as for functionally adaptive changes in response to lesions and neurodegenerative diseases. In addition to the pliability during postnatal maturation and during the restoration of disrupted functions, the visual system also maintains remarkable plasticity for encoding the specific shapes of figures to which we become familiar. This is known as perceptual learning, and it is important for rapid recognition of the learned shapes in complex environments and for enhanced sensitivity to delicate nuances of the learned stimulus features. Moreover, the visual system also exhibits fast functional switching capabilities, whereby response properties of neurons are dynamically adjusted by top-down influences for efficient processing of behaviorally relevant stimuli. The dynamic nature of neuronal responses is tightly coupled with the long-term plasticity seen in perceptual learning, as repeated performing of the same perceptual task, and therefore, repetitive invoking of top-down influences specific to the task, can potentiate the dynamic changes useful for solving the perceptual tasks, leading to encoding and retrieving of the implicit memory formed during perceptual learning.