Failure of Metacontrol: Breakdown in Behavioural Unity After Lesion of the Corpus Callosum and Inferomedial Frontal Lobes

Abstract

A right-handed man suffered aneurysmal haemorrhage with lesions of the genu and body of the corpus callosum and the inferomedial frontal lobes bilaterally (right more than left). He exhibited remarkable breakdown in behavioural unity characterized by conflict between the two sides of the body, actions inconsistent with verbalizations, and internal conflict over control of the left hand. A major feature of the deficit was its temporal variability. This is interpreted as reflecting intermittent failure of metacontrol processes, which are neural mechanisms for maintaining behavioural unity. Medial frontal structures and their interconnections through the corpus callosum appear particularly important in the maintenance of metacontrol.