Insular cortex and perception of temporal patterns

Abstract

Previous ablation studies have suggested that insular-temporal cortex in the cat brain is critical for the animal's ability to perceive changes in temporal sequences of stimuli. Implicit in these experiments has been the belief that the brain lesions must include both insular and temporal cortex in order to produce a behavioral deficit. Recent anatomical evidence indicates that the nature of the subcortical projections to insular and to temporal cortex is quite different. Thus we questioned the assumption of functional homogeneity of insular and temporal cortex implicit in previous ablation studies. The data of the present experiment indicate that cats prepared with bilateral lesions of insular cortex exhibit a severe deficit in temporal pattern discrimination, while animals prepared with temporal lesions show no such loss. The data suggest that performance deficits noted in earlier studies and attributed to insular-temporal cortical lesions may have actually been due to lesions of insular cortex.