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What Is the Lateral Hypothalamus?

Andrew Kirmayer
Andrew Kirmayer

The lateral hypothalamus is a part of the hypothalamus, located in the mid-brain, which controls hunger, thirst, and emotions. Neurons in this area respond to the signals of other areas of the brain and send signals to different regions. They are also in close proximity to the blood supply and can be influenced by such factors as glucose levels in the blood. Glucostatic receptors trigger a response in the lateral hypothalamus, resulting in the firing of neurons, which creates the feeling of hunger.

Emotional expression and pleasure seeking are also influenced by the lateral hypothalamus, and the structure also has the ability to raise heart rate and blood pressure. In contrast, the medial hypothalamus reduces heart rate and blood pressure, and sends signals to eliminate the feeling of hunger, so both hypothalamic structures serve as a counterbalance for one another. Circadian cycles are also regulated by the release of melatonin in the hypothalamus and pituitary gland. Changes in the lateral region can have an impact on sleep, depression, and appetite, and lead to depression-related conditions such as Seasonal Affective Disorder (SAD).

Sleep can be affected by changes to the lateral hypothalamus.
Sleep can be affected by changes to the lateral hypothalamus.

Changes in glucose levels and other substances in the blood influence the lateral hypothalamus, along with calorie levels. Hormones are secreted during digestion to control the digestive organs, and during this process other hormones are released by the solitary tract, a brain stem structure that projects into the hypothalamus. Osmoreceptors in the lateral hypothalamus help to determine whether water is needed or not.

The brain's hypothalamus holds the lateral hypothalamus.
The brain's hypothalamus holds the lateral hypothalamus.

Functions of the lateral hypothalamus and its projections into other brain regions seem to indicate it has a strong influence on reward and motivation. Activation of neurons is associated with cues related to receiving food or drugs. Reward-seeking and drug addiction are strongly related to activity in the lateral section. The hypothalamus as a whole tries to create a balance within the body, and its activities are mainly reflexive. Hunger, emotion, and pleasure are just a few things that the structure acts to maintain as required, and it also serves to trigger a need to escape dangerous or unpleasant conditions.

Changes in the lateral region can trigger seasonal affective disorder (SAD) and other mood disorders.
Changes in the lateral region can trigger seasonal affective disorder (SAD) and other mood disorders.

The lateral hypothalamus is strongly influenced by various metabolic processes and has a direct effect on emotional states and hunger. Damage to it can result in extreme depression or fits of rage, and aggression can be totally impeded if the lateral part is destroyed. Stimulation of appetite is also eliminated, and starvation can occur if the problem is not corrected.

Discussion Comments

wavy58

@Oceana – I think that a variety of things controlled by the lateral hypothalamus influence appetite and the love of food. Depression and happiness affect our desire to eat, so I would think that any emotional changes would go hand in hand with the strength of a person's appetite.

Some people tend to eat more when they are depressed, while others lose their appetite. Depression brought on by a general sadness with no direct cause can make you eat more, while depression caused by the death of a loved one or a heartbreak can cause you to lose your love of eating altogether.

I know when my boyfriend cheated on me, I didn't want to eat for about a week, but after that, I wanted to eat everything in sight. My depression led me from one extreme to another.

Oceana

I take much pleasure in eating. Perhaps this is because the lateral hypothalamus deals with both pleasure and appetite.

Pretty much everyone enjoys food, but it is my main reward. I look forward all day to a good dinner, and I salivate for dessert. It means more to me than a night out with friends or extra time to relax at home.

I enjoy cooking, and this is probably because I know it leads to eating! I just wonder if some people have more of a propensity toward seeking pleasure in food than others because of differences in the lateral hypothalamus.

shell4life

@orangey03 – Another way to exercise control over your hypothalamus is to take appetite suppressing drugs. If you feel hungry so often that you have become overweight, you can take a pill that will tweak your lateral hypothalamus and eating too much will no longer appeal to you.

I started taking such a drug last year, and I no longer had the pesky in between meal cravings that I always caved in to previously. I was able to think rationally about what I should eat, rather than what would taste so good.

Instead of pizza and cake, I would make a spinach salad with shrimp and broccoli stir fry. I knew I was getting the nutrients I needed, and the strong cravings no longer influenced my decisions.

orangey03

I never knew that one part of my brain could have control over so many things. I never really think about sleep and emotions being related to activities in my brain. I tend to relate them more with what's going on in my life and my feelings.

Now I see that my lateral hypothalamus could be what is giving me seasonal affective disorder. I sleep way too much in the winter, and I get so depressed that I feel I will never come out of it. I crave cookies, candy, and cakes, and I gain weight, which adds to my depression and sluggishness.

I know that my hypothalamus is affected by outside factors, like sunlight and what foods I choose to eat. I have to balance out what it makes me feel with how I want to feel, and in doing so, I can have more control over my emotions and cravings.

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    • Sleep can be affected by changes to the lateral hypothalamus.
      By: Konstantin Yuganov
      Sleep can be affected by changes to the lateral hypothalamus.
    • The brain's hypothalamus holds the lateral hypothalamus.
      By: Alila Medical Media
      The brain's hypothalamus holds the lateral hypothalamus.
    • Changes in the lateral region can trigger seasonal affective disorder (SAD) and other mood disorders.
      By: Boyarkina Marina
      Changes in the lateral region can trigger seasonal affective disorder (SAD) and other mood disorders.
    • Neurons firing in the lateral hypothalamus create the feeling of hunger.
      By: nebari
      Neurons firing in the lateral hypothalamus create the feeling of hunger.