Introduction to psychology assignment


Published on

The significance of the hypothalamus in the human mind

Published in: Technology, Health & Medicine
  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Introduction to psychology assignment

  1. 1. Lahey (2009:65) describes the hypothalamus as a “… a small, but vitally important part of the midbrain… the hypothalamus is intimately involved in our motives and emotions” it regulates our body temperature, sleep, endocrine gland activity, and resistance to diseases: controlling glandular secretions of the stomach and the intestines, and maintaining the normal pace and rhythm of such body functions as blood pressure and the heartbeat. The main thrust of this essay is to evaluate the role the hypothalamus plays in motivation. Zimbardo (1995) advocates that motivation refers to the starting, controlling, and upholding of corporal and psychic activities. It is declared by inner processes and variables which are used to explain behavioral changes. Further more motivation can be defined as a fundamental drive an organism has such as thirst, hunger, aggression, and lust. The physiological location and structure of the hypothalamus is that it is located in on either sides of the third ventricle, with the hypothalamic sulcus delineating its dorsal border; it extends from the rostral limit of the optic chiasm to the codal limit of the mammilary bodies. There are three important regions of the hypothalamus, the supraoptic region were there is a number of nuclei the prominent ones being the supraoptic and the Para ventricular. According to Dave (2010) these two nucleuses secrete vasopressin or antideuretic hormone, oxytocin and corticotrophin releasing hormone. They are transported down the axons from the cells to the blood stream through what is known as supraopticohypophysial tract. These hormones are claimed to motivate an organism to hydrate. They simply control an individual‟s water intake into the body. They drive an individual to drink or not to drink water. This is clinically proven by that individuals whose anterior hypothalamus has been been blocked through lesions, inhibit the production of antidiuratic hormone resulting in diabetes insipidus which is characterized by a loss of water in the kidney. This shows us that to some extent the hypothalamus plays a significant role in motivation. According to Dave (2010) the hypothalamus is perceived to contain the “Biological clock” that regulates certain body functions during the day, such as body temperature, hormone secretion, and hunger, or those that vary over a period of many days such as menstrual cycle. The projection from the retina to the suprachiasmic nucleus is thought to supply the clock with day- night information needed for the synchronizing diurnal rhythms which are a state of sleep
  2. 2. waking cycle. It then goes without saying that the hypothalamus plays an important role in motivating sleep or waking up. The tuberal region is commonly divided into medial and lateral parts by a plane through the fornix. The fornix, covered in the olfactory-limbic, is a fiber tract that originates in the hippocampus within the temporal lobe and courses rostrally along a C shaped course next to the lateral ventricle, then plunges into the hypothalamus where it terminates within the mammillary bodies (Dave, 2010). This shows that the hypothalamus has extensive influence on motivation because, because the medial part of the tuberal region contain two important nuclei the ventromedial nuclei which is said to control eating. The ventromedial nuclei is the lateral hypothalamic area supporting stimulation studies are given by (Daves,2010) to serve as illustration, the lesions of the ventromedial nuclei results in overeating in animals. It induces obesity, the ultimate damage of the lateral hypothalamic area results in anorexia because the animal would have stopped eating. It therefore shows that the hypothalamus is chiefly responsible for inducing motivational drives. According Daves (2010) the hypothalamus also controls emotional expression. In accordance to Daves (2010), recent evidence suggests there is direct projection from the hypothalamus to the preganglionic sympathetic neurons in the lateral horn of the spinal cord and to the preganglionic parasympathetic neurons in the dorsal motor nucleus of the vagus. In simple terms it would suggest that the hypothalamus contributes to the control of the involuntary bodily activities through the cells which originate from the hypothalamus and project to the viscera, but it also plays a significant influence in motivating emotion which can be visibly seen by the excessive pumping of the heart when someone has been startled or in fear. Delgado (1915) also makes a contemporal demonstration of the diencephalon control of behavior which does not preclude the hypothalamus. Delgado inserted electrodes in the caudate nucleus regions of a fighting bull, and managed to alter its aggressiveness in the bull fighting ring, according to Delgado the electrodes produced some euphoric feeling and having being located on the basal ganglia, therefore it suggests that the hypothalamus regions and hence the hypothalamus is responsible in motivating emotional and behavioral drives such as fear, aggression and fighting because the caudate nucleus is superimposed on it.
  3. 3. According to Dalgeish (1985) the hypothalamus is also responsible in homeostatic drives which motivate the body to control deviations from the optimal range of a regulated parameter, like temperature. It is detected by neurons concentrated in the periventricular zone of the hypothalamus; these neurons then produce an integrated response to bring the parameter back to its optimal value. It also shows again the role of the hypothalamus in motivation because once temperature anomalies have been dictated the hypothalamus has the „say‟ on what the body should do to get back to optimal temperature. According to Goodman and Gilman (1955) the hypothalamus contains a plethora of neurotransmitters which include GABA, glutamate, serotonin, dopamine, and norepinephrine. According to Milner and Old (1950), Dopamine plays a role in motivating behavior, it plays a role in addiction of drugs like heroin, nicotine, and tar, and since the neurotransmitter is released and controlled by the hypothalamus, the hypothalamus become the region responsible in stimulating pleasure. This is because if the hypothalamus is externally inhibited to release dopamine the animal addicted to heroin, it discontinues taking the drug but it leads the animal to have some kind of craving for the discontinued drug. According to Bancroft (1998) the hypothalamus due to being the most primitive part of the limbic system, it is the source from which all the emotions originate as raw, powerful, undirected feelings. This structure represents the emotional core of a human being. The hypothalamus is closely involved with all aspects of sexual behavior; posture, ejaculation, and hormonal secretions relating to pregnancy and menstrual cycle. Differences between the thalamus of a man and a woman indicate that the hypothalamus of females is more intricate and complex than males. Consideration of this fact yields insight on emotional gender differences. It shows yet again that the hypothalamus has a tremendous influence on sexual behavior and reproduction and hence it is directly involved in motivating copious arousal in both man and woman. However the hypothalamus may not be the only one capable of inducing motivation in animals. According to Beaumont (2008) the amygdala, the caudate cell, and the putamen have similar functions largely associated with those described for the hypothalamus. The hypothalamus plays a crucial role in storing and retrieving emotional memory. This memory may be a form of motivation to animals if there be a need for them to take on a “a fight or flight”. Papez (1937) concurs with this view by suggesting that the amygdala is the key critical structure for
  4. 4. motivating emotional expression. Support for this view arises from extensive work done with lesions of the amygdala, animals with lesions in the amygdale have difficulty learning associations between environmental stimuli and emotions hence with this view the amygdala also plays a role in motivation. Also, according to Feldman (2002) because of the sociocultural reasons, humans are motivated to diet and lose weight in most cases; it has become a fashionable trend in most westernized communities. Feldman (2002) further advocates that diet experts advise that people who want to lose weight should decrease the influence of external, social stimuli on eating behavior. This is an external stimulus which motivates them to eat disorderly. In light of this view the hypothalamus may not be the only motivator in human behavior. To conclude this essay the hypothalamus plays a significant role in motivating behavior to a greater extent regardless of the fact that there are other motivational mechanisms such as external stimuli and the occurrence of other molecular organs that directly influence a species behavior and drive to do things.