Ventromedial Prefrontal Cortex - Function

Function

Functional differences between the orbitofrontal and ventromedial areas of the pre-frontal cortex have not yet been clearly established, although the areas of the ventromedial cortex superior to the orbitofrontal cortex are much less associated with social functions and more with pure emotion regulation. Research in developmental neuroscience also suggested that neural networks in the ventromedial prefrontal cortex are rapidly developing during adolescence and young adulthood supporting emotion regulation through the amygdala, being associated with a decrease in cortisol levels. Compared to adults, lesions in the vmPFC of children result in more severe inhibition of social functions and emotional regulation.

Left lateral and medial orbitofrontal cortex areas were also measured to be highly active during guessing tasks. An increase in probabilistic scenario complexity was associated with orbitofrontal cortex activity level increase, therefore suggesting the special role that the ventromedial prefrontal cortex plays in decision making containing uncertainty. A study also indicated that patients with lesions in the ventromedial prefrontal cortex tend to have difficulties reacting to future consequences.

It is also suggested that the ventromedial prefrontal cortex also has a role in decision making in situations containing certainty. This demonstrates a form of myopia for the future because patients with lesions in the vmPFC generally only show concern for immediate prospects, regardless of past consequences or future outcomes. These results suggest that the vmPFC plays a significant role in decision making in general.

The ventromedial prefrontal cortex plays a key role in regulating emotional responses to stressful situations. It allows us to remain calm and suppress emotional urges. Patients with damage to the vmPFC are shown to possess serious impairments in decision and behavior control. These patients tend to exhibit negative personality changes, such as lack of empathy, irresponsibility, aggression, and poor decision making, traits that are also characteristic of psychopathic patients. A recent study on people with vmPFC damage showed a high correlation between emotional dysfunction and impaired competency in real-world activities, while there was no observed relationship between cognitive abilities and competency in real-world activities. This strongly points to the vmPFC's ability to regulate emotions as a key factor in the decision making process.

It is important to note that people with damage to the ventromedial prefrontal cortex still retain the ability to consciously make moral judgments without error, but only in hypothetical situations presented to them. There is a gap in reasoning when applying the same moral principles to similar situations in their own lives. The result is that you see people making decisions that are inconsistent with their self professed moral values.

The right half of the ventromedial prefrontal cortex was associated with regulating the interaction of cognition and affect in the production of empathic responses. Hedonic (pleasure) responses were also associations to orbitofrontal cortex activity level by Morten Kringelbach. This finding contributes findings suggesting ventromedial prefrontal cortex being associated with preference judgement, possibly assigning the ventromedial prefrontal cortex a key role in constructing one's self. Studies with PTSD also supported the idea that the ventromedial prefrontal cortex is an important component for reactivating past emotional associations and events, therefore essentially mediating pathogenesis of PTSD. Treatments geared to the activation of the ventromedial prefrontal cortex were therefore suggested for PTSD. The right half of the ventrolateral prefrontal cortex, being active during emotion regulation, was activated when participants were offered an unfair offer in a scenario. Specific deficits in reversal learning and decision-making have led to the hypothesis that the ventromedial prefrontal cortex is a major locus of dysfunction in the mild stages of the behavioural variant of frontotemporal dementia.

One particularly notable theory of vmPFC function is the somatic marker hypothesis, accredited to António Damásio. By this hypothesis, the vmPFC has a central role in adapting somatic markers—emotional associations, or associations between mental objects and visceral (bodily) feedback—for use in natural decision making. This account also gives the vmPFC a role in moderating emotions and emotional reactions because whether the vmPFC decides the markers are positive or negative affects the appropriate response in a particular situation.

Another role that the vmPFC plays is in the process of extinction, the gradual weakening and eventual cessation of a conditioned response. The specific role played by the vmPFC concerning extinction is not well understood, but it is believed that it plays a necessary role in the recall of extinction learning after a long period of time. Studies show that it aids in the consolidation of extinction learning. A separate study has implicated the correlation between the cortical thickness of the vmPFC and the degree of extinction memory. Patients with larger vmPFCs tended to have lower responses to the extinct conditioned stimulus, therefore suggesting a superior extinction memory.

Ventromedial prefrontal cortex lesions were also associated with a deficit in processing gender specific social cues. One experiment tested the ability of patients with vmPFC lesions to categorize gender-specific names, attributes, and attitudes compared to patients with dorsolateral prefrontal cortex lesions and control subjects. Whereas the patients with dorsolateral prefrontal cortex lesions performed similarly to the control subjects on tests indicating gender stereotypes, patients with ventromedial prefrontal cortex lesions demonstrated impaired stereotypic social knowledge.