Fun Paper 1 - Grade: A+ PDF

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This is the first paper of the semester. It is called: "Using the Correlational Method to Study the Divided Brain." ...

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Using the Correlational Method to Study the Divided Brain

The purpose of this paper is to evaluate the correlational method as a means for examining the relationship between functions of the left and right hemispheres. I will compare the performance of people with intact brains with the performance of so-called split-brain patients. In many ways, the brains of these two groups are very similar. 1a. The brainstem connects the cerebrum and the spinal cord in the body. The brainstem is a pivotal part of human anatomy as it encompasses several structures that are necessary for survival. The brainstem is necessary for survival because it gives you the ability to breathe and maintain bodily functions. The three main parts of the brainstem are the medulla oblongata, the reticular formation and the thalamus. The function of the medulla oblongata is to control your heart rate and respiration; It is located at the bottom of the brainstem. Next, the reticular formation runs along the inside of the brainstem and it controls the activation of consciousness in the body. The thalamus is located at the top of the brainstem and it relays information from sensory neurons and passes it to the cerebral cortex. There is no difference in the functionality of a normal brainstem and that of a split-brain brainstem. 1b. The hippocampus is in the limbic system which is between the cerebral cortex and the brainstem. The hippocampus is used for the storage of memories and new information. There are no differences in the anatomy of the normal hippocampus and the anatomy of the split-brain hippocampus. 1c. The corpus callosum serves as the bridge between the left and right cerebral hemispheres and it is located between them. It serves as the connection for information between each hemisphere. The difference between the anatomy of the normal corpus callous and that of the split-brain corpus callosum is that during split brain surgery the corpus callosum is severed which effectively splits the right and left hemisphere. 1d. The cerebral cortex is located on top of the brainstem and the limbic system. It contains four major parts of the brain: the occipital lobe, the temporal lobe, the parietal lobe and the frontal lobe. Since the cerebral cortex is made up of four different parts, each part serves a different purpose. The occipital lobe is primarily for processing vision. The temporal lobe is for smell and hearing. The parietal lobe is for touch. Lastly, the frontal lobe is mainly used for language processing, speech, and decision making. There are multiple differences in the function of the cerebral cortex in a split brain and an intact

brain. First, since the connection between the two hemispheres of the brain are cut off, there is a lack of communication between the two sides which can affect the visual fields of the split-brain patient. Further, the lack of communication between each hemisphere can hinder speech, visual pairs, and reasoning. Also, there is often a problem with body parts doing conflicting actions. The split-brain patient provides scientists with a window into the normal functions of the brain. 2a. Split brain patients have their corpus callosum severed through an operation called corpus callosotomy. Split brain patients usually suffer from refractory epilepsy. 2b. The left hemisphere relays information to the right side of the body so if you show a split-brain patient an object on their left side, they won’t “see” anything because the language hemisphere didn’t see anything in the right visual field. Since language function is lateralized to the left hemisphere, a split-brain patient won’t be able to interpret the objects that are in the right visual field. 2c. Laterality is the study of the hemispheres in the brain controlling specific parts/functions of the brain. In studying results with split brain patients, people can observe specifically which hemisphere of the brain is used in certain tasks. Further, the observations could help with understanding the connections of the brain with other parts of the body. Cognitive tests performed on split-brain patients have identified a division of labor between hemispheres. It is conceivable that function handled by the different hemisphere will show a strong relationship in the general population. 3a. The left hemisphere dominates in the brain’s ability to produce speech, comprehend language, make logical decisions, and ability to understand numbers/mathematical skills. Also, the left hemisphere is responsible for verbal memory. The right hemisphere is responsible for visual awareness, social communication, orientation, memory, and emotions. 3b. There is a strong chance of left hemisphere laterality in split brain patients because of their ability to isolate the more important uses of their left hemisphere. 3c. The correlational method supports laterality in split brains because it shows the extent to which there is dominance of one hemisphere in split brain patients. Further, if the average correlation coefficient is higher in the left hemisphere as opposed to the right hemisphere in split brain patients, it would show laterality in the left hemisphere.

Data were collected from a group of split-brain patients and a group from the general population to test the hypothesis using the correlational method. Each group completed three tasks shown previously to be lateralized: (1) a vocabulary test, (2) a logical reasoning task, and (3) a face recognition task. 4a. The vocabulary test and reasoning test is lateralized to the left side of the brain and the facial recognition task is lateralized to the right hemisphere. 4b. I think that there will be a higher correlation coefficient when comparing reasoning and vocabulary because there is laterality in the left hemisphere in split brain patients. Further, there will be a lower correlation coefficient when comparing the results of the facial recognition task to the vocabulary and reasoning tests because there is a decrease in laterality in the right hemisphere in split brain patients. 4c. Cognitive task (Intact Brain) Vocab & Face

r

I

II

III

0.6355774024

78, 176

116785.8469

60, 729.58

Face & Reason

0.8719018314

59.5755958

116785.8469

2299.83614

Vocab & Reason

0.7145185533

78, 176

59.5755958

1542.0002

Cognitive task (Split Brain) Vocab & Face

r

I

II

III

0.3447476334

88909

108737.5629

33897.21

Face & Reason

0.0424770057

95.90521461

108737.5629

137.1717892

Vocab & Reason

0.7156339566

88909

95.90521461

2089.704669

The results of the correlational method were valuable in addressing the hypothesis under study. However, future investigations may need to adopt techniques that improve upon those used here. 5a. If there is left hemisphere laterality in split brain patients, there would be high scores in the logical reasoning and vocabulary tests. The results of the correlational analysis are consistent with my hypothesis. Split brain patients have a correlational coefficient of 0.72 in the vocabulary and reasoning tests; The value of 0.72 in that category shows a high positive correlation in left side laterality in split brain patients. On the other hand, the correlational coefficient for the reasoning/ face test was 0.04 and the

correlational coefficient for the vocabulary/face test was 0.35 which further solidifies my hypothesis that there is laterality in the left hemisphere for split brains. 5b. One part of the results that would need my hypothesis to go under more investigation is the act that both groups of participants, intact and split brains, received the same approximate correlational coefficient of 0.72 in the vocabulary and reasoning test; In other words, there is also left hemisphere laterality in intact participants, although it is split brain participants because it is the highest coefficient out of all the tests. 5c. One feature of the correlational technique that could be improved is the use of more participants to gain a better perspective on laterality in both split and intact brains. Also, if there were multiple tests done on the same hemisphere on the brain instead of just two, the results would be more accurate if there are a wide range of tests and participants. In addition, another factor that could change the results of laterality is how long the patient has had a split brain, if the participant received a corpus callosotomy at a young age, it would have the time to allow the brain’s plasticity to take over certain functions which in return would alter the laterality of the brain. 5d. Correlational studies should be used to supplement experiments to get the most accurate results. 5e. To explore left hemisphere laterality in split brain patients there should be multiple tests on: logic, math skills, language comprehension and speech production; These tests would point to left hemisphere dominance in split brain patients....