Recognition of emotional face expressions and amygdala pathology.

The amygdala is often damaged in patients with temporal lobe epilepsy, either because of the primary epileptogenic disease (e.g. sclerosis or encephalitis) or because of secondary effects of surgical interventions (e.g. lobectomy). In humans, the amygdala has been associated with a range of important emotional and social functions, in particular with deficits in emotion recognition from faces. Here we review data from recent neuropsychological research illustrating the amygdala role in processing facial expressions. We describe behavioural findings subsequent to focal lesions and possible factors that may influence the nature and severity of deficits in patients. Both bilateral and unilateral amygdala damage can impair the recog - nition of facial emotions, especially fear, but such deficits are not always present and not always specific. Moreover, not all components of emotion or fear processing are impaired after amygdala damage. Dissociations have been reported between deficits in the recognition of emotions from the face of other people, and intact ability in the production of emotions in one’s own facial expression after amygdala damage. In addition,residual implicit effects during processing of emotional stimuli can also be preserved in some patients with amygdala lesion. A great variability in the effects of amygdala damage on emotion processing has been observed and suggests that other important factors have to be considered: these include the aetiology of damage, and the age of disease onset. We propose that a more detailed assessment of emotional processing in patients with temporal lobe epilepsy may provide not only novel information about the role of amygdala in humans, but also useful clinical measures to assess temporal lobe functions in epilepsy patients.