Subcortex Diencephalon lesions from the view of the Neurologist and the Neurosurgeon :: Medical Medicine Essays

Subcortex Diencephalon lesions from the view of the Neurologist and the Neurosurgeon The diencephalon, which includes the thalamus, hypothalamus, and subthalamus of the brain will be discussed in this project paper however, the main focus will by on the hypothalamus of the diencephalon structure. To begin a brief review of the functions of the thalamus and hypothalamus, the thalamus is the input center for sensory information and the output center for motor information. The hypothalamus regulates hunger, thirst, and the body’s temperature. The hypothalamus also releases hormones and plays a role in sexual responses and behaviors, and our circadian rhythms (Campbell, 1999). The hypothalamus can be affected in many ways from genetics/hormones to injury from a lesion or accident. If a female fetus is exposed to too much testosterone during their critical period the hypothalamus can become masculinized which would lean create masculine behaviors in the female. Those fetuses that are male but are androgen insensitive have femininized hypothalamuses and portray feminine behaviors (Kalat, 2004). Damage such as a lesion to the lateral hypothalamus can cause an individual to refuse food and/or water depending on where the lesion is located. The opposite of true of damage occurs in the medial hypothalamus, the individual will over eat or drink (Kalat, 2004). The Neurologist The neurologist can perform many experiments on the hypothalamus by placing electrodes on the different parts, which simulates what could happen to the individual if this portion of the hypothalamus became injured. Studies have shown that the hypothalamus control functions such as mating, urination and defecation, eating and drinking, temperature regulation (through homeostasis), and circadian rhythms (Farr, 2002). The anterior portion of the hypothalamus is involved in copulation however; the septal region is also involved. When electrical stimulation is directed to this area the individual will experiences sexual emotions and thoughts. A study was done on cats where electrical stimulation on the anterior portion of the hypothalamus was done thus showing that the cat acted as though it was going to urinate or defecate along with the other processes such as hiding/covering the feces (Farr, 2002). One of the most important functions of the hypothalamus is in the lateral and ventromedial regions, these areas in the hypothalamus control eating and drinking. If a lesion in the lateral region of the hypothalamus is created experimentally or damage is done to