Plasticity in human blindsight.

A subject with an unually large cortical scotoma, leaving a 9 degrees hemifield of vision in each eye, showed improvement with practice in pointing to an oscillating target positioned within the scotoma. The practice effect transferred to low-contrast targets and to stationary ones, though oscillating targets were always located more accurately. Following practice, the subject reported improved confidence in visual orientation. Results are interpreted in the context of the contrast between the functions of two visual systems (subcortical and cortical) present in normal humans.