An anatomical study of the effects of unilateral removal of sensorimotor cortex in infant monkeys on the subcortical projections of the contralateral sensorimotor cortex.

Following removal of the motor or sensorimotor cortex in infant monkeys the projections of the remaining motor or sensorimotor cortex have been studied after long-term survival to look for anomalous projections from these areas. The patterns of degeneration resulting from lesions of the remaining motor or sensorimotor cortex corresponded to those found in normal adult monkeys in the spinal cord, pontine nuclei, superior colliculus, parvocellular red nucleus, subthalamic nucleus and thalamus. Sparse degeneration was found in the magnocellular part of the contralateral red nucleus which has not been described in normal animals and there is also the possibility of an increase in the crossed corticostriate projection. Infant monkeys do not form anomalous projections comparable to those found in the rat following neonatal sensorimotor cortex lesions.