from single-unit electrodes in monkeys have shown similar activation in the left amygdala. A man with confined damage in the right amygdala could not produce a startle response. The activity (measured by a PET scan) in the right amygdala correlated to the number of emotionally arousing film clips capable of being recalled in patients. Unilateral activation of the amygdala due to fearful stimuli may also produce unilateral activation of other regions. The right middle temporal gyrus, right brainstem, left hippocampus, right cerebellum, right fuisform gyrus, and left lingual gyrus were also activated during fearful stimuli. Activation of multiple brain regions both indicates that emotions are processed in many parts of the brain and that emotions are complex. The amygdala probably plays a role in the conscious processing of emotion. The left amygdala was activated during the processing of conscious stimuli while the right amygdala was active during the processing of nonconscous stimuli. Anterior cingulate cortex (ACC) The anterior cingulate cortex (ACC) plays a role in a variety of functions including emotional ones. The ACC may be important in conscious awareness of emotion. Damage to the ACC is associated with decreased SCR to physical and psychological stimuli. Bilateral and unilateral damage both resulted in decreased SCR indicates that the right and left ACC's may specialized in certain aspects of emotional response. Anterior insula (AI) The left anterior insula (AI) increasingly responds to increasingly fearful stimuli. The AI may also be involved in the conscious experience of emotion. Implications Phenomena such as emotional lateralization may help describe how emotions arise, persist, and alter our behavior. Understanding emotional lateralization will help scientists understand emotion in general. Emotional lateralization may also play a role in psychological disorders such as depression and schizophrenia. Future treatment of psychological disorders may have more targeted neurological treatments rather than ingested drugs. Symptoms that arise from confined regions of damage usually have stereotypical emotional and behavioral changes. Diagnosis for locating damaged regions that process emotion may aided by noticeable emotional changes categorized under one of the lateralized emotional control systems. Diagnosis and treatment for cardiovascular irregularities that arises from emotions states could be aided by understanding the physical basis of the psychological influences. Instead of treating the cardiovascular irregularities for psychological issues, treatment could target the lateralized brain regions. Limitation of Studies Like all human based scientific experiments there are limitations to what researchers can do. Attempting to study