IOWA CITY, Iowa -- Decision making highly depends on one's emotions. When a person cannot generate emotional responses to different circumstances, which can happen when certain parts of the brain become damaged, the person's ability to make good decisions may be disturbed. But, depending on the location of the brain damage, how decision making is affected may be different, according to findings from a recent University of Iowa Health Care study.
Researchers found that lesions of the amygdala disrupt emotional conditioning, whereas lesions to the ventromedial prefrontal (VMF) cortex cause an individual to have difficulty with conflict situations. These results confirm the Somatic Marker Hypothesis, a theory advanced by Antonio Damasio, M.D., UI professor and head of neurology. Damasio had proposed that there is a neural circuit critical for processing emotional signals. He predicted that lesions in any elements of that circuit would result in defects in decision making.
"In essence, damage in either of the two structures (the amygdala and VMF cortex) lead to impairments in decision making," said Antoine Bechara, M.D., Ph.D., UI assistant professor of neurology and lead author of the study that appears in the July issue of the Journal of Neuroscience. "However, the underlying mechanisms responsible for the impairments are different. In real life, the two types of patients exhibit two types of decision-making deficits."
Individuals with amygdala damage have trouble attaching emotional significance
to a previously neutral event. For example, walking along a road is a neutral,
routine event. However, if a person were mugged while walking along this road,
that person would inevitably experience fear when he or she walked along the
road again. Now, imagine that the individual could not associate this particular
road with fear. The person may decide to continue to walk along the road and
possibly subject himself or herself to another harm in the fut
Contact: Jennifer Cronin
University of Iowa