The hypothalamus has a cone-shaped structure in the brain which is located just below the thalamus and above the pituitary gland.
It could probably be said that the hypothalamus is one of the busiest part of the brain. It is a very important part of the limbic system in the mediation of endocrine, autonomic and behavioural functions (5). It is in charge of regulating homeostatic processes in the body, it works as a thermostat , for example if one’s room gets very cold it conveys this information and turns its thermostat on, or vice versa if one’s room is too hot it turns off (4).The hypothalamus is thought to have “the biological clock” which regulates some of the body functions at different times of the day and that differ for a period of time such as the menstrual cycle. The hypothalamus is involved in, concentration of fluids, it controls the release of eight main hormones in the body; storage of nutrients and mediates several aspects of emotion responses and motivation. It is in control of hunger, thirst, levels of pleasure, anger, sexual behaviour, aggression and the autonomous nerves system (ANS).The hypothalamus, as well as having its own receptors, it gets information from a number of external and internal sources and it also controls the pituitary gland secretions. Information about blood pressure from the vagus nerve, input about light and darkness from the optic nerve, and the discharge of hormones from the pituitary are examples of the many stimuli from ‘high centres’ performing on the hypothalamus.
Although hypothalamic disorders seem to occur from brain tumours and not being present from birth (3), the hypothalamus seems to be the least well understood area from the hypothalamo-pituitary axis (9).The thalamus is situated near the central area of the brain, the forebrain. It is known as the relay station for sensory information before it is passed to the cortex; it is involved in the functions of sleep and attention, in coordination with other brain structures besides being responsible for motor control in the body. Experiments with monkeys give the result that the thalamic nucleus are densely interconnected with prefrontal cortex (PFC) which is crucial to new learning and relearning.In addition some have shown that the mediodorsal thalamus is impaired in object recognition and stimulus-reward association. These latest findings prove the importance of the thalamic nucleus in memory processing and during new learning process.
Lesioning some of the thalamic nucleus in monkeys provoked a high margin of error in new learning (8). Nuclei groups are directly related to the thalamus, receive pain afferents and have an important role on pain perception, also with extend damage to some nuclei groups movement disorders may occur (11).Based on investigation during surgery in a patient with thalamic stroke, it was identified that thalamic reorganization is possible and may help recovery from such stroke (10). In conclusion it laid out in is paper some roles of the Limbic System and its interchangeable connectivity. For instance we could see that the amygdala, the hippocampus, the hypothalamus and the thalamus all have in some way to do with emotion and memory, therefore the so called the emotion brain.Such connection is essential to their efficient functions. Even though there still a lot unknown about the Limbic System what has been learnt is definitely encouraged scientists and researchers to carry on looking into it in more detail. As mention above, environmental reasons are one of the elements that have recently been taken into consideration by some investigators.
All in all the role of the Limbic System is crucial to the human beings life.References:(8) – Depression May Shrink Brain Structure , Sheline YI et al.Depression Duration but not Age Predicts Hippocampal Volume Loss in Medically Healthy Women with Recurrent Major Depression. The Journal of Neuroscience, vol.
19, no. 12, pp. 5034-5043, June 15, 1999. Adapted from materials provided by Washington University School Of Medicine, material available online from, http://www. sciencedaily. com/releases/1999/06/990616063411.
htm, retrieved in October 2008. (4) – Endocrine System, material available online from www. kidshealth. org, retrieved in April 2008.