ABSTRACT
The primary sensory maps on the neocortex are the first means for representing information at the cortical level, but their subsequent manipulation and association is still required to allow for polymodal and supramodal information processing. The fact that children and animals commonly have considerable difficulty in distinguishing between horizontal mirror-image letters but have less difficulty distinguishing between vertical mirror-images suggests that there is something special about the left-right pairs. In a series of studies, R. W. Doty and colleagues have examined the mechanisms of callosal transfer of learned responses in monkeys and have advocated the idea that unilateral engram formation may not be unique to man. When the cortex itself is directly stimulated, however, the absence of brainstem arousal may be the crucial factor preventing bilateral engram formation. That the corpus callosum is in fact involved in bilateral responses has been demonstrated by the fact that when the corpus callosum is severed, many such binocularly driven cells become monocularly driven.
