Occipital Lobe

The occipital lobe is the most posterior portion of the cerebral cortex of the human brain, at the back of the head. It is the smallest of the four lobes of each cerebral hemisphere and is separated from the parietal lobe by calcarine fissure. The occipital lobe is defined as the part of the cerebral cortex that lies underneath the occipital bone.

The occipital lobe is the visual center of the brain as it contains the primary visual cortex. Each visual cortex receives sensory information from the outside half of the retina on the same side of the head and from the inside half of the retina on the other side of the head. The cuneus, also called the Brodmann's area 17, receives visual information from the contralateral superior retina representing the inferior visual field. The lingula receives information from the contralateral inferior retina representing the superior visual field. The retinal inputs pass through a "way station" in the lateral geniculate nucleus of the thalamus before projecting to the cortex.

Prefrontal Cortex

The prefrontal cortex is the anterior portion of the frontal lobes of the cerebrum. It lies in front of the motor and premotor areas. The prefrontal cortex is thought to be involved in planning complex cognitive behavior and in the expression of personality and appropriate social behavior. The prefrontal cortex can be divided into three basic areas: the orbitofrontal and ventromedial areas; the dorsolateral prefrontal cortex; the anterior and ventral cingulate cortex.

The prefrontal cortex has been shown to participate in the association of events separated by time and is responsible for the executive functions, which include mediating conflicting thoughts, making choices, and governing social control. When the pathways between the prefrontal cortex and the rest of the brain are damaged due to head injury, massive personality changes can result.

Many diseases, such as schizophrenia, bipolar disorder and ADHD, have been related to dysfunction of the prefrontal cortex, and thus this area of the brain offers the potential for new treatments of these diseases. Markers of inhibitory neurotransmission are altered in the prefrontal cortex (PFC) of subjects with schizophrenia, and several lines of evidence suggest that these alterations may be most prominent in the subset of GABA-containing neurons that express the calcium-binding protein, parvalbumin (PV).

The prefrontal cortex responds mostly to stimuli signaling the need for movement; nevertheless it is also responsible for many other specialized functions. It gets information from all sensory systems and can integrate a large amount of information. It has been shown that the prefrontal cortex is responsible for working memory. Working memory is defined as the information that is currently available in memory for working on a problem.