The Brain & Behavior

An Overview of Function & Damage Impacts

The human brain is tremendously complex in its function and structure. The knowledge of the human brain has until recently been limited by virtue of the sensitive nature of the organ. Researchers have been limited to understanding the brain through study of damage and disease which reflect loss of cognitive functions. The development of technologies such as the Magnetic Resonance Imager (MRI) has opened a new window on brain research. Devices such as the MRI allow researchers to study the brain and its functions using imagery. This has eliminated the dangers associated with surgery and other methods. This noninvasive means of studying the brain has led to the ability to correlate brain function and structure with behavior. The correlation of behavior and function has provided a great deal of knowledge concerning the importance of the temporal and frontal lobes of the brain.

Cerebral Cortex

The cerebral cortex comprises “a large, deeply wrinkled sheet of neurons, or nerve cells, on the surface of the brain’s two hemispheres”. This area of the brain is referred to as right and left hemispheres. The cerebral cortex is the largest area of the brain and controls “sensation, thought, comprehension, higher cognition, ideas, language, memory and emotion” (Pinel, 2011). Both hemispheres have four lobes. Each lobe of the brain is responsible for a vital function (Pinel, 2011). These functions include:

· The frontal lobe is responsible for controlling cognitive functions including decision-making, goal setting and planning (Pinel, 2011).

· The parietal lobe is responsible for concentration, language understanding, vision, and sensory and spatial orientation (Pinel, 2011).

· The occipital lobe is responsible for processing visual stimuli which is received from the temporal and parietal lobes (Pinel, 2011)

· The temporal lobe is responsible for receiving visual and auditory information and providing this information to the temporal lobe. This lobe also plays a role in language comprehension, olfactory sense, and balance (Pinel, 2011).

The frontal lobe and the temporal lobe have been shown to affect behavior in a many different ways. In MRI studies, the frontal lobe becomes active when performing ethical reasoning and decision making (Pinel, 2011). Further evidence of this connection can be seen in cases in which the frontal lobe has been damaged. Cases of damage in this area have been characterized by poor impulse control, violent behavior, and rage issues (Coon & Mitterer, 2013). The temporal lobe has been identified with reasoning and in cases in which this area has been damaged the results have included dementia and mania (Coon & Mitterer, 2013). Temporal lobe damage has been associated with paranoia, aggression, and depression (Pinel, 2011).

Damage to the frontal and temporal lobes often take the form of Broca’s and Wernicke’s aphasias (NIH, 2008). Aphasia is an impairment of a person’s ability to express and understand language (NIH, 2008). Aphasia is typically the result of a stroke or traumatic head injury. Less common causes are diseases including dysarthria or apraxia.

Broca’s aphasia resulting from injury to the frontal lobe causes individuals to utter only short phrases with tremendous difficulty. Individuals suffering from Broca’s aphasia understand speech but their inability to communicate causes them to become frustrated and angry (NIH, 2008). Unlike Broca’s aphasia, Wernicke’s aphasia is caused by injury to the left temporal lobe. Individuals who are afflicted with Wernicke’s aphasia speak in long sentences that are mostly unintelligible. Wernicke’s aphasia victims are typically not aware of their condition (NIH, 2008).

Under normal developmental and unimpaired functioning, the brains lobes ensure that humans process information and stimuli correctly. One of the most glaring examples of how important the brain’s structures are to behavior can be seen in the case of Phineas Gage. Phineas Gage was a worker who was injured in an accident in which an iron pole pierced his skull below his left eye and exited from the top left of his forehead damaging his lobes. Prior to the accident, Gage was described as a well-mannered likable person. After the accident Gage’s behavior was completely transformed:

…fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged than they are abandoned (Goodwin, 2008).

Gage and other cases of this nature show the importance of brain structure and how it relates with behavior and proper thought function. Although incidents of this nature are rare lobe and brain damage may occur more often than one might think. Today, researchers are exploring head injuries and are discovering that even what was once considered mild injuries may be the cause of personality changes in people.

Brain injury can also contribute to psychiatric issues including depression, severe anxiety, substance abuse, or obsessive compulsive disorder. Some survivors experience post-traumatic stress disorder (PTSD) as a consequence of the circumstances and medical events that caused the brain injury (Cromer, 2012).

This area of research may yield new clues and discoveries in behavioral and neuroscience. Understanding that even mild damage to the brain may cause issues might explain how many disorders and syndromes are acquired. Further research in this area is needed.

References

Baumgardner, S. R., & Crothers, M. K. (2009). Positive psychology. Upper Saddle River, NJ: Prentice Hall.

Coon, D., & Mitterer, J. O. (2013). Introduction to psychology: Gateways to mind and behavior (13th ed.). Belmont, CA: Wadsworth Cengage Learning.

Cromer, J. M. (2012, March 9). After Brain Injury: The Dark Side of Personality Change Part I. Retrieved from Psychology Today: https://www.psychologytoday.com/blog/professor-cromer-learns-read/201203/after-brain-injury-the-dark-side-personality-change-part-i

Goodwin, C. J. (2008). A history of modern psychology (3rd ed.). Hoboken, NJ: Wiley.

Kowalski, R., & Westen, D. (2009). Psychology (5th ed.). Hoboken, NJ: Wiley.

NIH. (2008, October). Aphasia. Retrieved from NIH: http://www.nidcd.nih.gov/health/voice/pages/aphasia.aspx

Pinel, J. P. (2011). Biopsychology, Eighth Edition. Boston, Mass: Allyn & Bacon. Pearson Education, Inc.

NIH. (2008, October). Aphasia. Retrieved from NIH: http://www.nidcd.nih.gov/health/voice/pages/aphasia.aspx

Panel, J. P. (2011). Biopsychology, Eighth Edition. Boston, Mass: Allyn & Bacon. Pearson Education, Inc.

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