Ventromedial prefrontal cortex
From Psy3241
The ventromedial prefrontal cortex (VMF) is located under the frontal cortex, inside the orbitofrontal base of the anterior frontal lobe, adjacent to the midline. It has connections with the amygdala, hippocampus, temporal visual association areas and the dorsolateral prefrontal cortex. The VMF integrates information about emotions, the environment and memory.
Role of the VMF
A function of the VMF is to interpret somatic markers and incorporate the emotions into decision-making. Those with damage to the VMF may invest poorly, lose jobs and relationships, and act impulsively.
Not only do people with VMF damage make poor decisions, they are unable to learn from their mistakes by using somatic information from previous outcomes. This may help to explain why they perform so poorly on the on the Iowa gambling task. Their poor decision-making may be a result of an inability to incorporate somatic information triggered by the amygdala. However, unlike those with amygdala damage, people with VMF damage are able to generate a conditioned fear response.
The lack of somatic interpretation also influences the patient's social behavior. Those with damage to their VMF are typically unable to “read” others non-verbal emotional expressions or body language. Since the feelings of regret and embarrassment are also somatic functions, they do not realize when they are acting socially inappropriate. Following damage, patient's personalities often change drastically. One such case of this was Phineas Gage, who suffered damage after being impaled with a tamping iron. His family and friends noticed marked differences in his personality. Once motivated and responsible, Gage became lazy, disinhibited and unpredictable.
Patients with VMF damage retain normal intellectual abilities, such as language, memory and attention. They also usually score within the normal range score normally on tests of executive function, such as the Wisconsin card sort test.
A study by Koenigs et al (2007) compared the performance of those with VMF damage to control participants. They administered a series of situations that were either non-moral, impersonal and moral or personal and moral. Those with VMF damage responded very rationally to personal moral problems, where the control patients did not. VMF patients also opted for the immoral but rational solutions more than control participants. This study was compared to the results of VMF patients and the Iowa Gambling Task to conclude that those with VMF damage often act without weighing the consequences.
References
Bechara, A., Damasio, H., & Damasio, A., R. (2000). Emotion, decision making and the orbitofrontal cortex. Cerebral Cortex, 10(3), 295-307.
Bechara, A., Damasio, D. Tranel and Damasio, A., R. (2005). The iowa gambling task and the somatic marker hypothesis: Some questions and answers. Trends in Cognitive Sciences, 9(4), 159-162.
Facundo, M., Sahakian, B., Clark, L., Rogers, R., Antoun, N., Aitken, M., & Robbins, T. (2002). Decision-making processes following damage to the prefrontal cortex. Brain, 124, 624-639.
Wagar, B., M & Thargard, P. (2004). Spiking phineas gage: A neurocomputational theory of cognitive-affective integration in decision making. Psychological Review, 111, 67-79.
