SOMATOSENSORY LOSS IN MONKEYS AFTER IPSILATERAL CORTICAL ABLATION

Abstract

This experiment investiaged the question of whether or not unilateral brain damage imparis ipsilateral as well as contralateral sensory function. Monkeys (Macaca mulatta) with unilateral cortical ablation of either the sensorimotor region (including precentral and supplementary motor areas, somatosensory I and II, and the posterior parietal lobe) or of nonsensorimotor regions (the remainder of the cortex of the hemisphere) were tested on a variety of tactual discriminations with the ipsilateral hand. Compared with the nonsensorimotor group, as well as with unoperated controls, the sensorimotor group showed a retardation in learning difficult form discriminations and an elevation of differential thresholds for roughness, but not for size.