Neuropsychology of Emotion and Emotional Disorders: An Overview and Research Directions

In the past 25 years, the study of neural mechanisms involved in emotional processing has flourished, although findings in this area emanate from the end of the nineteenth century. By emotion, we refer to reactions to an appropriately evocative stimulus involving cognitive appraisal (or perception), expressive motoric behaviour, subjective experience (or feelings), physiological arousal, and goal-directed behaviour (Plutchik, 1984). Researchers have identified numerous neuroanatomical structures and neurophysiological systems that modulate emotion at cortical, subcortical, and limbic levels of the nervous system. From a new psychological perspective, a range of theories has been proposed to account for cerebral hemispheric specialization of emotion (e.g., right hemisphere, valence, and motoric-direction hypotheses) and for componential and modular processing. Evidence for these various theories stems from both clinical observation and experimental studies. involving normal, neurological, and psychiatric populations. Experimental studies have employed a variety of methodologies, including behavioural paradigms, the natural lesion method. neurosurgical procedures, electrophysiological techniques, and hemodynamic neuroimaging. In addition to delineating brain mechanisms involved in aspects of emotional processing, this growing body of research has wide-ranging clinical implications for the assessment, diagnosis, treatment, and rehabilitation of neuropsychiatric populations suffering from deficits in emotional processing.