The brain is an incredibly complex organ, responsible for managing everything from breathing and physical coordination to logic, language and artistic expression. While all animals have brains, they don't all possess the higher reasoning and thinking abilities of humans, owing largely to the fact that of all animals, humans have the most well-developed cerebral cortex. The cerebral cortex is the convoluted, grayish portion of the brain that sits most superior and forward in the skull. It consists of many subdivisions that specialize in different areas of thinking and reasoning.
Prefrontal Cortex
A 2001 article in the "Annual Review of Neuroscience" notes that the prefrontal cortex---the area of the brain closest to the forehead and just above the eyes---is important to logic and reasoning, thinking and personality. In fact, damage to this part of the brain can result in tremendous personality change, as exemplified by the "frontal lobotomy." In this semi-surgical procedure, historically performed to relieve certain psychological conditions including psychosis, physicians disconnected the prefrontal cortex from the rest of the brain. Post-lobotomy, the patient retained all normal physical function, including speech and mobility, but the personality changed markedly.
Wernicke's Area
In "Foundations of Physiological Psychology," author Neil Carlson, Ph.D., notes that Wernicke's area is a specialized portion of the posterior temporal lobe, located on the left side of the brain, somewhat above and behind the ear. Discovered in the late 1800s, Wernicke's area is involved in linguistic expression---people with damage to this part of the brain can comprehend speech, but are unable to repeat words when asked to do so. While they maintain the ability to produce sound, they are generally incapable of using meaningful language---their sentences contain nonsense words and don't make sense.
Broca's Area
Dr. Carlson notes that another area of the brain, called Broca's area, is used for cognitive tasks, particularly those that involve memory. This part of the brain is located near the intersection of the frontal and temporal lobes on the left side, in a deep fold called the interior frontal gyrus. Originally, scientists thought that Broca's area was involved in speech formation; however, after several patients with damage to Broca's area were observed to have maintained their ability to speak but lost the ability to perform cognitive and memory-related tasks, the theory regarding Broca's area function changed.
Sensorimotor Cortex
Extending from the top of the brain near the crown of the head down toward the ears on either side, there are two strips of cerebral cortex called the motor cortex (further forward) and the sensory cortex (further back). These strips of brain were once thought to function independently of each other, but recently have been found to share so much function that they are now commonly referred to in tandem as the sensorimotor cortex. This portion of the brain is involved in learned and reflexive physical movements and tasks. A study reported by the website Science Daily found that even thinking about physical tasks produced excitation in the sensorimotor cortex, indicating that it was involved not only in executing, but also in planning coordinated motion.
References
- "Annual Review of Neuroscience"; An integrative theory of prefrontal cortex function; E. Miller and J. Cohen; 2001
- "Foundations of Physiological Psychology"; Neil Carlson, Ph.D.; 2004
- Science Daily: Sensorimotor Cortex Excitation
