Introduction
The brain is said to be a complex organ that enables us to perform many functions among them is to think, feel, see, hear, taste and smell. In Addition it also controls our body and receives analyses and stores information. (Willingham, 2007) Cognition can be termed as the act or process of knowing. This encompasses a range of high level mental functions which include the ability to learn and remember information: organize, plan and problem-solve; focus, maintain and shift attention as necessary. It also includes understanding and using language, accurately perceiving the environment, and performing calculations. (Macmillan, 2000)
The Role of the Brain in Cognitive Functions
Cognitive processes are either natural or artificial. These processes are analysed from different perspectives from different contexts notably in the field of linguistics, psychology, anesthesia, neurology, systemics and computer science (Grafman et al, 2002).In psychology the concept of cognition is noted to be closely related to abstract concepts such as mind, reasoning, perception, intelligence; learning is among many others that describe the capabilities of the mind and the expected properties of an artificial mind. Cognition is considered an abstract property of advanced living organisms and as such studied as direct property of a brain at the factual and symbolic levels. (Harrison and Owen, 2002)
There were two major views on the localization of higher cognitive functions. Phrenology, one of the two views supposed that all cognitive and personality traits had particular areas of the brain that is in charge of each of them. This view was discarded because most its components did not conform to scientific forms. The second view said that higher cognitive functions and traits could only be kept in the cerebral cortex which functioned as a whole but any part of it could suffice to the other’s functions. It also stipulated that an effect of cognitive functions because of cortical lesions was caused by damage of tissues and not the localization of it as it were.
This approach was widely accepted until some clinical observations contradicted it specifically the observation that aphasias happened when one of the two specific areas were lesioned.The two areas are the Broca’s area and the Wernicke’s area of the cortex which are localized in the left hemisphere of the brain.(Grafman et al,2002)
The Broca’s area is found underneath the motor cortex that controls face movement and language expression. Patients with lesions in this region understand complex abstract concepts in conversations and language but their talk is unclear since the utterances are random though with proper intonation. A speech could for instance sound like “…..train came children food.
Wernicke’s area is in the left temporal auditory cortex. Patients with Wernicke’s aphasia have a problem with understanding but not hearing. Patients can understand simple requests but they cannot understand even simple conversation. These patients however unlike Broca’s produce incongruent talk. They will make complete phrases that make sense but will be out of context.
A question like “How are you feeling?” can be answered “Yesterday was a hot day.”(Grafman et al, 2002).
Harrison and Owen (2002) have said in their book that most scientists embrace a midway version between holism and phrenology especially with the discovery of association cortices. High- order processing is the work of the entire cortex while specific areas of the cortex are required for sensory input. Study of vision as a sensory system helped in finding out that a lot of processing was done by the system itself while depending on cortical localization in what is called high-order sensory cortices like detection of direction, intensity ad other combined attributes of visual stimuli. A restricted grouping of two sensory inputs named associated cortices elicited response in some areas
The associated areas of the cortex provide a base for thought and perception. However, no visible changes in behaviour is observed upon stimulation of these areas even though they obtain sensory input from the sensory system then further relay it to the motor cortex. The cortex has three areas; the first is parietotemporal-occipital cortex.It receives auditory, somatosensory and visual projection. In addition it receives high order input from their respective cortices thus thought to integrate information from these sensory modalities necessary for language (Willingham, 2007).
The story of Phineas gage as found in book helps to elaborate the functions of the brain’s parts in social behaviour and moral reasoning. Gage was working on a railroad in Vermont in 1848 when an explosion blew an iron bar through the top of his head producing massive injury to his brain more specially the frontal lobe. Edward Williams a physician who examined Gage remembered that he” talked so rationally and was so willing to answer questions, that he directed his inquiries to him rather than the men who were with him at the time of the accident and who were standing about at the time”(Macmillan, 2000).
Initial examination indicated that his motor and language control regions had been affected which turned out to be wrong. Since these parts remained functional; it shows that the brain is not modular whereby different regions performed different functions. On the other hand it is an undifferentiated mass working holistically (Boller et al, 2000).
However, Gage was said to have changed personality as opposed to his previous one. He was fitful, irreverent and indulging at times in the grossest profanity (which was not his custom), he was formerly thoughtful, fastidious and a responsible man. Gage’s frontal lobe which were most affected were now believed to be responsible for moral reasoning, decision-making and inhibition. His accident was hint to the major roles of the frontal lobe in social behavior and moral reasoning (Macmillan, 2000).
Conclusion
In conclusion, the various parts of the brain work together in achieving the cognitive functions which include being able to learn new concepts, for the brain to retain this information so that it can be retrieved upon need. In addition, the brain serves in controlling ones attention and in using language alongside analyzing the environment.
References
Harrison, E. J. and Owen M.A. (2002). Cognitive Deficits in Brain Disorders..Informa Health Care.
Willingham, D.T, (2007). Cognition: The thinking animal.3rd edition. Prentice Hall
Grafman, J. et al. (2002). Handbook of neurology: The role of anatomical segregation in the frontal lobe. Elsevier Health.
Boller, F., et al (2000). Handbook of Neurology: Language and Aphasia.2nd ed.Elsevier Health Sciences.
Macmillan, M. (2002). An Odd Kind of Fame: Stories of Phineas Gage. MIT Press.