Dorsolateral Prefrontal Cortex

The dorsolateral prefrontal cortex is located between the superior frontal gyrus and the inferior frontal gyrus of the frontal lobe, covering the middle central gyrus and straddling the anterior halves of the superior frontal sulcus and the inferior frontal sulcus. The dorsolateral prefrontal cortex is the last area to develop (myelinate) in the human cerebrum. This area mainly receives its blood supply from the middle cerebral artery. With respect to neurotransmitter systems, there is evidence that dopamine plays a particularly important role in the dorsolateral prefrontal cortex.

The dorsolateral prefrontal cortex is connected to the orbitofrontal cortex, and to a variety of brain areas, which include the thalamus, parts of the basal ganglia, the hippocampus, and primary and secondary association areas of neocortex, including posterior temporal, parietal, and occipital lobes.

The dorsolateral prefrontal cortex plays an important role in the integration of sensory and mnemonic information and the regulation of intellectual function and action. It is the highest cortical area responsible for organization, motor planning, and regulation. It is also involved in working memory. Nevertheless, the dorsolateral prefrontal cortex is not exclusively responsible for the executive functions. The complex human mental activity require the additional cortical and subcortical circuits that the dorsolateral prefrontal cortex is connected with.

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.