Social and emotional functions in three patients with medial frontal lobe damage including the anterior cingulate cortex

Abstract

Introduction: The aim of this study was to explore social and emotional functions in patients with medial frontal damage including the anterior cingulate cortex (ACC).

Methods: Three patients with medial frontal lobe lesions primarily involving the ACC performed tasks on motivational decision making, emotional facial expression recognition, and social cognition, including theory of mind (ToM). Their performance on these tasks was compared with age and education matched healthy controls.

Results: Patient performance on the motivational decision making and social situations tasks did not differ from controls. Selective emotional facial expression recognition impairment for fear was evident in one patient with a unilateral right ACC lesion (patient 3). ToM impairment was present in only one patient with a bilateral ACC lesion (patient 2). In contrast, the two patients with unilateral right ACC lesions had intact ToM (patients 1 and 3).

Conclusions: These findings suggest that medial frontal lobe lesions primarily involving the ACC do not appear to critically disrupt motivational decision making or social situation processing. The ACC plays a role in processing particular types of emotion (fear). Bilateral ACC damage impairs ToM processing, but unilateral damage to the right ACC is not sufficient to disrupt ToM.

Figure 1

Sagittal, coronal and axial T1 weighted MRI images of the anterior cingulate cortex lesions of the three patients. (a) Patient 1, showing a postoperative unilateral right ACC lesion extending anteriorly toward the frontal pole (BA 32, 24), posteriorly to mid cingulate (BA 24), and inferiorly to involve the genual region (BA 32, 25). (b) Patient 2, showing a postoperative MRI of the location of surgical debulking of the bilateral tumour from a left dorsal approach. The tumour involved ACC bilaterally (BA 32, 24). (c) Patient 3, showing a haematoma involving the right ACC including dorsal and ventral regions (BA 32, 24) but sparing the subcallosal area (BA 25). (See http://www.fil.ion.ucl.ac.uk/-'hugo/ACCscans/SupplementaryACCscans.html for additional MRI slices showing the full extent of the lesion in each patient.)