Central nervous system structure and function

¶ … human Central Nervous System plays a large role in governing personality. The Central Nervous System (CNS) is made up of the brain and spinal cord. The good deal of our knowledge about how the brain influences personality comes from early studies of how brain damage impacts personality. The case of Phineas Gage demonstrates that link between the left temporal lobe and personality characteristics like working for a delayed the word, aggression, and emotional expression. Techniques like positron emission topography (PET) and magnetic resonance imaging (MRI) have also allowed us in insight into the link between the CNS and personality, as high as the study of personality changes in Alzheimer's disease.

The central nervous system (CNS) in humans is made up of the brain and spinal cord. In contrast, the peripheral nervous system includes the peripheral nerves. In the CNS, the spinal cord conducts sensory information from the peripheral nervous system to the brain. The brain receives this sensory information, processes and interprets it, and produces appropriate motor outputs (Medline plus).

Much of our understanding of how the brain influences personality comes from the study of individuals with brain damage. This damage may have occurred through surgery, tumor, stroke, or trauma to CNS (ThinkQuest).

Perhaps the most famous individual case that links the CNS to personality through brain damage is that of Phineas Gage. In 1848, Phineas Gage is left temporal lobe was punctured by a large metal rod. Gage survived, but his personality underwent a radical transformation. Prior to the damage to CNS, Gage was likable, conscientious, and hard-working. After the damage to CNS, Gage exhibited obscene behavior, could not work toward a goal, and became impetuous. Subsequent research showed that the temporal lobe, which was virtually destroyed in Gage's case, controls aggression, emotional expression, and working for delayed rewards (ThinkQuest).

Brain-imaging techniques such as positron emission topography (PET) and magnetic resonance imaging (MRI) scans have also helped reveal how the brain controls personality. These techniques can allow comparisons between the functioning of normal and abnormal brains, and how these comparisons relate to personality (ThinkQuest). MRI and PET scans can also be used to determine which areas of the brain are activated during specific tasks, and how all personality characteristics relate to function of the brain.

Several areas of the CNS have been linked to unique personality characteristics. In particular, recent research has shown how an area of the CNS called the amygdala influences personality. The amygdala is strongly associated with emotional processing in the brain, and is a pea-sized new center of the brain (Dye).

A recent Stanford University study used functional MRI scans to investigate the connection between personality and the amygdala. The researchers selected 15 subjects, and tested the subjects to determine their degree of extroversion (outgoing and optimistic), or whether these individuals for slightly worried, insecure, and potentially shy. Participants were then showed a series of photographs, while being scanned by the functional MRI. In all subjects, an unpleasant or threatening expression on the face was associated with activity in the amygdala. However, the two groups differed significantly in their reaction to a happy face. Specifically, extroverted individuals showed a consistent activation of the amygdala in response to a happy face. In contrast, shy individuals showed little or no reaction to the happy face (Dye).

Diseases like Alzheimer's disease can also offer an interesting insight into how the Central Nervous System controls are personality. It Alzheimer's disease, large numbers of brain cells die over time. The death of these brain cells results in dementia, mental deterioration, and eventual death. Alzheimer's symptoms include problems with abstract thinking, impaired language and social skills, loss of short- and long-term memory, and significant personality changes (Windsor).