Interhemispheric and intrahemispheric control of emotion: a focus on unilateral brain damage.

Neocortical contributions to emotional processing are discussed. First, parameters critical to the neuropsychological study of emotion are examined: interhemispheric (right, left) and intrahemispheric (anterior, posterior) factors, processing mode (expression, perception), and communication channel (facial, prosodic, lexical). Second, neuropsychological theories of emotion are described: right-hemisphere and valence hypotheses. Third, experimental studies of right-brain-damaged, left-brain-damaged, and normal adults are reviewed, on the basis of mode and channel, with a focus on stroke. Findings support right cerebral hemispheric dominance for emotion, regardless of valence and channel, and are more consistent for perception than expression. When lesion site is a factor, posterior sites are important for perception and anterior ones for expression. Finally, clinical implications are suggested for aphasia rehabilitation and for assessment of affect in neurological disorders.