Tuesday, June 2, 2009

Orbitofrontal Cortex

The orbitofrontal cortex is the foremost part of the frontal lobe, lying on the roof of the orbit. The orbitofrontal cortex is involved in cognitive processes such as decision-making. Considerable individual variability has been found in the orbitofrontal cortex of both humans and non-human primates. Because of its functions in emotion and reward, the orbitofrontal cortex is considered by some to be a part of the limbic system. It has been proposed that the orbitofrontal cortex is involved in sensory integration, in representing the affective value of reinforcers, and in decision-making and expectation. It is thought to regulate planning behavior associated with sensitivity to reward and punishment.

Although the orbitofrontal cortex is one of the least explored and least understood regions of the human cerebral cortex, clinical evidence suggests that the orbitofrontal cortex is involved in critical human functions, such as social adjustment and the control of mood, drive and responsibility, traits that are crucial in defining the ‘personality’ of an individual. Phineas Gage is a paradigmatic patient, who, after suffering major destruction of the orbital and medial prefrontal cortices in both hemispheres, was portrayed as no longer being himself.