What is the substantia nigra pars reticulata (SNr)?
It is a part of the substantia nigra. (1)
What is NOT the substantia nigra pars reticulata?
the substantia nigra pars compacta (SNc)
What does the substantia nigra pars reticulata contain?
It contains mostly GABAergic neurons (i.e., neurons that release neurotransmitter GABA, or gamma-aminobutyric acid). These neurons play a major role in the output of the basal ganglia to the thalamus, helping regulate motor and non-motor behavior. (2)
In Parkinson’s disease, the loss of dopamine in the striatum (due to degeneration of dopaminergic neurons in the SNc) leads to an increase in the activity of the SNr and a related structure, the internal segment of the globus pallidus (GPi). (3) This increased activity leads to an excess of inhibitory signals being sent to the thalamus and the cortex, which is thought to contribute to the motor symptoms seen in Parkinson’s disease. (3)
Resources
1. ChatGPT 4, 6/3/23, “What is the substantia nigra?”
2. ChatGPT 4, 6/3/23, “Are nigrostriatal neurons located in both the substantia nigra pars compacts AND the substantia nigra pars reticulata?”
3. ChatGPT 4, 6/3/23, “So the substantia nigra pars reticulata really has nothing to do with Parkinson’s disease?”
