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Brainstem, Tuberomammillary Nucleus & Locus Coeruleus

Written by Joe Cohen, BS | Last updated:
Medically reviewed by
SelfDecode Science Team | Written by Joe Cohen, BS | Last updated:

Neuroscientists believe that the brain creates synchronized output by acting as a complex and self-regulated system. The brain regions discussed in this post are no exception. The brainstem, tuberomammillary nucleus, and locus coeruleus have collectively been implicated in consciousness, memory, sleep, and mood. Read on to learn the basic neuroscience.

Brain Regions in this Post: Before You Read On

Our Scope

This post focuses on the neuroscience of the lateral hypothalamus. Its contents are solely informational. Talk to your healthcare provider if you experience any neurological symptoms.

Be Careful Not to Misinterpret the Symptoms Listed Below

Problems with the brain regions discussed below (the brainstem, tuberomammillary nucleus, and locus coeruleus) can cause different symptoms. Each person’s symptoms will depend on the affected area, the types of hormones involved, and other health conditions.

Some possible symptoms that may signal a hypothalamus problem are included below, but these lists are in no way exhaustive. Also, the symptoms described below are not specific to problems with these brain regions but may have many possible underlying causes.

See your doctor if you experience any of the symptoms mentioned in this post.

Your doctor should diagnose and treat the underlying cause of your symptoms. In some cases, he or she may recommend scheduling an appointment with a neurologist who is qualified to do detailed brain function assessments.

The Brainstem


  • Sensations of pain, temperature, and itch
  • Maintaining consciousness
  • Regulating the sleep cycle
  • Regulating heart rate, breathing, sleeping, and eating.

Potential Symptoms of Brainstem problems

  • Visual disturbances
  • Pupil abnormalities
  • Changes in sensation
  • Muscle weakness
  • Hearing problems
  • Vertigo
  • Swallowing
  • Speech difficulty
  • Voice change
  • Coordination problems
  • Altered heart rate
  • Altered blood pressure
  • Altered sleeping cycle
  • “brain fog”

Tuberomammillary nucleus (limbic system)

Potential Symptoms of Tuberomammillary problems

  • Fatigue
  • Impaired memory
  • Impaired cognitive function
  • Impaired sleep
  • Weight problems

About The Tuberomammillary System

The tuberomammillary nucleus is located within the hypothalamus. It consists of histamine-releasing neurons. Scientists believe it is involved in [1+]:

  • Wakefulness
  • Cognitive function
  • Memory
  • Sleep
  • Weight

Locus Coeruleus

Function & Location

Some medications including norepinephrine reuptake inhibitors are believed to work through this area [2].

Research continues to reveal the roles of norepinephrine — from regulating the stress response to helping form memories to maintaining attention to initiating arousal.

Studies suggest that the locus coeruleus may be responsible for mediating many of the sympathetic effects during stress [3].

Scientists consider that the most important functions influenced by this system are:

  • Wakefulness
  • Sleep-wake cycle
  • Attention
  • Memory
  • Motivation
  • Behavioral flexibility
  • Behavioral control
  • Stress (psychological)
  • Emotions
  • Neuroplasticity
  • Posture and balance

Activation by Stress

Researchers think that once this system is activated by stress, it will respond by increasing norepinephrine secretion. Increased norepinephrine, in turn, may:

  • Alter cognitive function (through the prefrontal cortex)
  • Increase motivation (through nucleus accumbens)
  • Activate the hypothalamic-pituitary-adrenal axis
  • Increase the sympathetic (fight or flight)/inhibit parasympathetic (rest and digest) system (through the brainstem).

The released norepinephrine can act on α2 receptors to increase working memory, while an excess of norepinephrine may decrease working memory by binding to the lower-affinity α1 receptors.

Activation of the locus coeruleus via the amygdala has been implicated as a major factor in stress-induced disorders, especially PTSD. Combat-related PTSD to be associated with fewer neurons in the locus coeruleus (LC). However, more research is needed to confirm this association [4].

Experimental data suggest that the locus coeruleus is almost completely inactivated in REM sleep [5].

Alzheimer’s Disease

Limited data suggest that there may be up to 80% loss of locus coeruleus neurons in Alzheimer’s disease [6].

According to one yet-to-be-verified theory, norepinephrine from locus coeruleus cells may provide an anti-inflammatory environment around the neurons, glial cells, and blood vessels in the neocortex and hippocampus. It is also hypothesized to suppress amyloid beta production, but this hasn’t been proven.


  • Norepinephrine

Potential Symptoms of Locus Coeruleus problems

  • Depression
  • Anxiety
  • Panic disorder
  • PTSD
  • ADHD
  • Parkinson’s disease
  • Alzheimer’s disease

Work with your doctor or another health care professional for an accurate diagnosis.

About the Author

Joe Cohen, BS

Joe Cohen, BS

Joe Cohen flipped the script on conventional and alternative medicine…and it worked. Growing up, he suffered from inflammation, brain fog, fatigue, digestive problems, insomnia, anxiety, and other issues that were poorly understood in traditional healthcare. Frustrated by the lack of good information and tools, Joe decided to embark on a learning journey to decode his DNA and track his biomarkers in search of better health. Through this personalized approach, he discovered his genetic weaknesses and was able to optimize his health 10X better than he ever thought was possible. Based on his own health success, he went on to found SelfDecode, the world’s first direct-to-consumer DNA analyzer & precision health tool that utilizes AI-driven polygenic risk scoring to produce accurate insights and health recommendations. Today, SelfDecode has helped over 100,000 people understand how to get healthier using their DNA and labs.
Joe is a thriving entrepreneur, with a mission of empowering people to take advantage of the precision health revolution and uncover insights from their DNA and biomarkers so that we can all feel great all of the time.


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