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Subcortex Diencephalon lesions from the view of the Neurologist and the Neurosurgeon

Satisfactory 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
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