Substantia Nigra: What to Know

Medically Reviewed by Jabeen Begum, MD on October 04, 2022
4 min read

The substantia nigra is a motor nucleus located in the basal ganglia of the midbrain. This brain structure contributes to the body's cognitive and motor functions by sending signals to initiate or inhibit movements and rewards. Because the substantia nigra is an essential component of daily functions, damage or degeneration that affects it can result in a wide range of brain disorders or diseases.  

Some disorders associated with the substantia nigra are unpredictable and therefore unavoidable. However, it's possible to prevent or delay certain conditions by maintaining a healthy diet and exercise regimen, wearing protective equipment, and scheduling regular checkups with a physician.

The substantia nigra (SN) is a small yet essential brain structure that plays a critical role in controlling your body's movements. By producing dopamine, the substantia nigra controls motor functions and muscle tone. 

Interesting facts about the substantia nigra:

  • The substantia nigra is a significant producer of dopamine in the body. Consequently, this aspect of the brain structure plays essential roles in other functions and behaviors relating to addiction, emotion, and learning. 
  • Substantia nigra, which means "black substance" in Latin, gets its name from the melanin-rich cells that compose this section of brain structure. Compared to the rest of the brain, which is usually gray or pink, the substantia nigra appears almost black.

The substantia nigra is the primary brain structure found in the basal ganglia, which is a group of interconnected brain structures that control functions like cognition and learning, voluntary movement, emotions and reward functions, and cognitive planning.

The substantia nigra is responsible for producing dopamine, which functions as a reward chemical that primarily affects the central nervous system. Dopamine is a neurotransmitter that also communicates with various brain structures in order to execute voluntary motor functions.

The substantia nigra anatomy is made up of two parts: the pars compacta (SNpc) and the pars reticulata (SNpr).  

Pars compacta. The SNpc is responsible for releasing dopamine to the striatum, another brain structure found within the basal ganglia.  After receiving neurotransmitters from the SNpc, the striatum signals the basal ganglia, and motor function is initiated. 

Pars reticulata. The SNpr is composed of neurons that play an important role in seizure control, eye movement, and cognition. These neurons intercept, redirect, and inhibit signals that shouldn't be sent to the muscles.

The substantia nigra location is between the midbrain and the diencephalon, a brain structure that connects the midbrain to the forebrain. Conventionally, the substantia nigra is attributed to the midbrain due to its various functions.

The midbrain is located at the topmost section of the brainstem. The midbrain is composed of numerous cranial nerve nuclei, pathways, and reflex centers.

Several symptoms could indicate that your substantia nigra has sustained damage. The symptoms will depend on the condition and may require medical testing. 

You may experience:

  • Shakiness or tremors when your body is at rest
  • Difficulty initiating movement
  • Balance and coordination issues
  • Inability to focus or problem-solve
  • Uncontrollable eye movements

If you're concerned that your substantia nigra has been damaged, it's important to make an appointment with a medical professional. Any possible substantia nigra disease requires a medical diagnosis. 

In the case of more severe symptoms, seek immediate medical attention.

Conditions that affect the substantia nigra include: 

Parkinson's disease. This is a progressive neurodegenerative disorder that affects the nervous system and motor function. Symptoms occur in stages that range from mild to severe. 

Symptoms of Parkinson's disease may include:

  • Tremors in your hands or fingers
  • Uncontrollable movements
  • Impaired coordination or balance
  • Stiff muscles
  • Changes in speech or writing

If you're experiencing any of these symptoms, contact a doctor to be evaluated. Severe symptoms may require immediate emergency medical attention. 

Huntington's disease. This is a rare genetic disease that causes the degeneration of nerve cells in the brain over time. Symptoms typically don't surface until a person is in their 30s or 40s. 

Symptoms of Huntington's disease may include: 

  • Difficulty making decisions
  • Mood swings
  • Memory loss
  • Difficulty walking
  • Difficulty breathing
  • Weight loss

Huntington's disease requires diagnosis from a medical professional. If you're experiencing any severe symptoms, seek immediate medical attention. 

Tourette's syndrome. This disorder involves involuntary movement and sounds called tics. Tics typically surface in children between the ages of two and 15 years old.

Symptoms of Tourette's syndrome may include:

  • Simple tics involving a limited number of muscle groups
  • Complex tics involving a large number of muscle groups

Some conditions affecting the substantia nigra are unpredictable and can't be prevented. Others, however, can be prevented or delayed in the following ways:

  • Eat a balanced diet. Maintaining a healthy diet is better for your heart health and weight, which promotes a healthy brain. 
  • Set aside time for physical activity each week. Whether you walk, run, or anything in between, physical activity can prevent or delay certain ailments, such as high blood pressure, heart attack, or stroke. 
  • Protect your body with safety equipment. Certain activities or jobs may require safety equipment, such as a helmet or other protective headgear. Because some head injuries can cause permanent brain damage, it's essential to wear safety gear when it's recommended. 
  • Get regular checkups. Brain disorders often get worse over time, so it's important to catch them early on and start receiving treatment.