Hypothalamus

The hypothalamus (the red spot in the drawing) lies diagonally below the thalamus, just above the pituitary gland, and also just above the point where the optic nerves cross. It is part of the diencephalon and the limbic system.

The limbic system deals with emotion, pleasure, motivation, and emotional memory. Researchers are finding more and more brain areas associated with emotion.

Function

The hypothalamus has multiple functions:

• control of the hormonal system. The hypothalamus can release hormones itself and can stimulate the pituitary gland, which in turn produces hormones
• regulation of the autonomic nervous system, including breathing, heart rate, blood pressure, and regulating body temperature
• preparing the body for action and contributing to the body's recovery at rest
• the connections between the hypothalamus and the midbrain play a role in aggression
• regulation of feelings of hunger and thirst, satiety, as well as sexual arousal and the sleep-wake cycle

Symptoms of damage to the hypothalamus

(NB! each injury and each human being is different)

• lack of motivation (of various behaviors)
• changed libido
• changed sleep-wake schedule, sleepiness
• narcolepsy: a sleep disorder in which a deficiency of orexin, a substance produced in the hypothalamus, may play an important role
• altered menstrual pattern
• feelings of euphoria
• hyperactivity
• agitation or aggression: the hypothalamus is involved in the regulation of the autonomic nervous system and physical responses to emotions. Damage can therefore contribute to dysregulated emotional responses.
• body temperature that is too high or too low, inability to cool down or warm up the body
• lack of hunger or thirst sensations resulting in insufficient food or drink intake
• excessive hunger or thirst sensations resulting in excessive food or drink intake
• diabetes insipidus: a condition characterized by excessive thirst (polydipsia) and frequent urination (polyuria)
• cluster headaches and migraines: in both conditions, there are indications of hypothalamic involvement, including in the regulation of attacks and the biological rhythm. This does not automatically mean that the hypothalamus is damaged
   

Nuclei of the hypothalamus

Each nucleus has a different function. It is clear to the physician that if there are specific symptoms, he or she may suspect damage to a particular nucleus.

• the medial preoptic nucleus for sex hormones
• the suprachiasmatic nucleus for the day-night rhythm
• the anterior nucleus for temperature regulation
• the paraventricular nucleus for the regulation of blood pressure and urine production (water balance/antidiuretic hormone (ADH), oxytocin, and corticotropin-releasing hormone)
• the supraoptic nucleus produces antidiuretic hormone (ADH), which is involved in the regulation of blood pressure and urine production, and oxytocin.
• the dorsomedial nucleus (in animals, it has been shown to cause rough behavior)
• the ventromedial nucleus for the feeling of satiety regarding food
• the infundibular (arc-shaped) nucleus for dopamine production
• the mammillary bodies receive information from the hippocampus and transmit it to the thalamus. Damage can cause memory problems.
• the posterior hypothalamic nucleus for thermoregulation
  
• the lateral hypothalamic nucleus stimulates eating.

In summary

• blood pressure
  
• heart rate
• regulating body temperature
• cooling down in the heat and warming up in the cold, perceiving how warm or cold it is
• sleep-wake rhythm
• action and rest, as well as fight or flight
• hunger (appetite and satiety) and thirst
  
• urine regulation (water and salt balance)
• reproduction
  
• sexual arousal
  
• controlling the pituitary gland

According to research, some cells are more sensitive to the aging process and brain aging than others.

For instance, the neurons of the hypothalamus and the cells of the third ventricle, which regulate hormones and essential bodily functions, were found to be the most sensitive to aging.

This page has been checked by P.A.W. Frima-Verhoeven, Neurologist at Breinpoli

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