Tuesday, March 13, 2012

Essay on Brain Function

Essay on Brain Function

What Are the Main Structural Divisions (Lobes) In the Brain, And How Do They Relate to Psychological Functions?
 1. Introduction
Brain is said to the center of the nervous system of the human being. Brain consists of four main structural divisions or lobes. They are: frontal, parietal, occipital and temporal. All lobes carry particular function and dysfunction of any can bring the person serious troubles.

In this paper I will describe four lobes of the brain, as well as identify how these lobes relate to psychological functions.

2. Frontal Lobes
Frontal lobes are responsible for reasoning, planning, movements, emotions, parts of speech and problem solving functions. Frontal lobes are considered to be the center of the emotional control and the shelter of human’s personality. It is the only part of the brain where lesions are capable of causing a wide range of different symptoms. The frontal lobes are involves in memory, spontaneity, initiation, language impulse control, motor functions, as well as sexual and social behavior. These lobes are very vulnerable to injury because of their location at the cranium front. They are also situated in proximity to sphenoid wing.

In the frontal lobes there are asymmetrical differences that are very important, as left part is involved in control of the language related movement and the right is important to non-verbal abilities. But many researchers claim that this distinction is not absolute and with many people, both lobes for both functions are involved.

When the motor function of the frontal lobe is disturbed, it is usually characterized by fine movements’ loss, as well as diminishing of strength in arms, hands and fingers. People with damaged frontal lobe can have spontaneous facial expressions or even difficulties in speaking (Brown, 1972).

But what is interesting about damages of the frontal lobes, it almost has no influence on the person’s IQ level. And as IQ tests involve convergent, rather then divergent thinking, it is possible to assume that frontal lobe damage is influencing divergent thinking, or problem solving ability.

Behavioral spontaneity is said to be the other area associated with the frontal lobes. It had been notices that people with damaged frontal lobes speak fewer words or spoke two much (left and right frontal lesions) (Kolb and Milner, 1981).

People that experiences damage of the frontal lobes can also have difficulties in interpreting and expressing feedbacks from the environment. They may not react to questions, behave risk and not comply with set rules (Miller, 1985).

Frontal lobes damage also can greatly influence person’s social behavior, as the personality can be significantly changed after the injury, especially of both. Left frontal lobe damage leads to pseudodepression and right- to pseudopsychopatic. Abnormal sexual behavior can be introduced after orbital frontal damage. Or sexual interest can be reduced due to dorolateral lesions (Walker and Blummer, 1975).

In order to check the functioning of the frontal lobe, following tests are involved: Wisconsin Card Sorting, Token Test and Finger Tapping.

3. Parietal Lobes
Parietal lobes are responsible for orientation, recognition, stimuli perception and movement. They can be divided into two functional parts, where one is involved in perception and sensation and the other is dealing with sensory input integration with visual system. The sensory information is integrated and the perception is formed, and then the spatial coordinate system is constructed to show world around. When parietal lobes are damaged, patients experience striking deficits.

Gerstmann’s Syndrome can be the result of the left parietal lobe damage. This syndrome includes the confusion of right and left, difficulties in writing, as well as difficulties with math. People cannot perceive object in the normal manner and have language disorders (aphasia).

When the right parietal lobe is damaged it can result in neglecting the part of body or space. The person will not be able to get dressed and wash himself. The person will not be able to write and draw.

Balint’s Syndrome is caused by the damage of large lesions to both sides (bi-lateral damage).This syndrome is also called motor and visual attention syndrome and is characterized by the inability to control gaze, to integrate components of the visual scene and reach object using visual guidance (Westmoreland et al., 1994).

When the area between temporal and parietal lobes is damages, it can lead to memory and personality deficits.

4. Occipital Lobes
Occipital lobes are responsible basically for visual processing and are the center of visual perception system. They are not very much vulnerable to injuries due to their location at the back of the brain, but nevertheless any injury can produce changes to the visual-perception system. Occipital lobe’s peristriate region is involved in visuospacial processing, movement and color discrimination. When one side of occipital lobe is damaged it can result in homonomous vision loss with the same field cut in both eyes. Disorders of this lobe can also cause visual illusions and hallucinations. Visual illusions appear in the form of distorted objects and abnormal coloring of those. Visual hallucinations, when there are no external stimuli for such an image, appear after temporal lobe seizures or lesions to occipital part.

Word blindness is another problem with occipital lobe injury; the person just becomes unable to recognize words. The person with occipital lobe problems is also unable to recognize movements of the objects, which is called movement agnosia, and also have difficulties with reading and writing. The patient can even loose sight or obtain what is called cortical blindness, when the person has normal eyes, reflexes and eye movements, but lacks the perception pattern and has no idea of visual information.

5. Temporal Lobe
Temporal lobe is responsible for perception and recognition of auditory stimuli. It has two essential sulci running parallel Sylvian fissure, and they separate temporal lobe into three gyri: superior temporal, middle temporal and inferior temporal.

This lobe type is very important for language, especially in managing lexical and semantic information. There are eight main symptoms of the temporal lobe damage, which include disturbance of selective attention of auditory, of visual input, auditory sensation and perception, disorders of visual perception, impaired organization and categorization of verbal material, as well as long-term memory, altered personality and affective behavior, as well as altered sexual behavior, and finally disturbance of language comprehension (Kolb and Wishaw, 1990). Damage of temporal lobes leads to selective attention to visual or auditory input. When the left side of the lobe is injured it results in decreased recall of visual and verbal content. When the right side is damaged, it results in tonal sequences decreased recognition and decrease in musical abilities. Temporal lobes are in the sensory input primary organization. Temporal lobe seizures can also have serious effects on the personality of the individual.

6. Conclusion
In the conclusion I would like to summarize that there are four structural divisions of the brain- frontal, parietal, occipital and temporal. They all perform their functions, even though sometimes those functions are interrelated. Frontal lobes are responsible for planning, movements, parts of speech, problem solving, emotions and reasoning. Parietal lobes care about orientation, recognition, movement and stimuli perception. Occipital lobes are responsible for visual processing and temporal- for perception and recognition of auditory stimuli. Any damages caused to any lobe can result in serious psychological problems.

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