Receptive Field Development and Individual Experience

Abstract

The normal adult functional organization is not present in cat or rabbit cortex before the age at which eye-opening normally occurs. There is a high percentage of atypically responsive and of nonresponsive neurons. Two particular aspects of receptive field organization, bionocular and orientation specificity, are either not present or are present in a much smaller fraction of neurons than in normal adults. In the cat and the rabbit the time course of the appearance of normal percentages of orientation-specific units is markedly delayed by delaying eye-opening. The same is true for binocular specificity in cats, which may be prevented altogether from developing. Accompanying the delayed development of orientation specificity in rabbits are elevated percentages of atypical and nonresponsive neurons. These represent a retention of the neonatal state, not a deterioration. The same may be true in the cat. Strabisimic animals reach an end state characterized by a vast reduction in binocularity, and tube-reared animals reach an end state with an absence of neurons selective for nonexperienced orientation.