Impaired facial affect recognition and emotional changes in subjects with transmodal cortical lesions

The present study attempts to identify cortical lesion sites associated with deficits in the decoding of emotional facial expressions and with changes of emotional states. A consecutive sample of 68 subjects with lesions caused by microsurgical tumor resection or by intracerebral hemorrhage were compared with 16 clinical and 15 healthy control subjects. A set of neuropsychological test measures - two experimental tasks requiring the sorting and rating of emotional facial expressions, and an adjective checklist as a measure of mood state - were administered. An analysis according to the functional properties of the areas with lesions revealed that subjects with combined lesions of heteromodal and limbic/ paralimbic cortices of the right hemisphere showed the strongest deficits in the decoding of emotional facial expressions. In contrast, subjects with lesions of limbic/paralimbic cortices alone, or subjects with lesions of unimodal or primary motor or sensory cortices displayed only minor deficits. Subjects with combined lesions of heteromodal and limbic/paralimbic cortices of the left hemisphere showed the most negative mood states. Our results suggest that heteromodal and limbic/paralimbic, i.e. transmodal cortices may be viewed as 'bottleneck' structures for the decoding of emotional facial expressions and for the modulation of mood states. Lesions of transmodal cortices deprive limbic structures of one of their main sources of input and are therefore likely to produce deficits in various forms of complex human emotional-cognitive behaviors and emotional states.