Dopamine Circuits: Investigating Relationships Between Dopamine Dysregulation and Midbrain Circuits

Daphne Siozios ’23

Figure 1: Dopamine is an important neuromodulator of the central nervous system, playing an important role in a wide range of processes including memory processing, learning, and habit formation.

Dopamine (DA) is a behavioral neuromodulator that controls the function of the central nervous system through a variety of roles from memory processing and perception to learning and habit formation. The mesolimbic DA pathway, which travels specifically through the midbrain, has been linked to neural deficits caused by a lack of dopamine neurons in the striatum. While research regarding DA’s dysregulation has laid the groundwork for determining various roles for DA based on which region of the brain it lies in, there is still insubstantial evidence to indicate exactly how each pathway controls behavior and induces disease. Professor Shaoyu Ge of the Department of Neurobiology and Behavior at Stony Brook University conducted a literature review to evaluate whether dopamine dysregulation, which leads to the eventual prognosis of Parkinson’s disease, is specific to the entire striatum in the brain or more distinct subregions by synthesizing information on neural circuits of the dorsal striatum, ventral striatum, and hippocampus relative to how they regulate brain function.

To properly evaluate the DA regulation of behavior, only two neuron pathways were analyzed: Dopamine Receptor-1 (D1R) vs. Dopamine Receptor-2 (D2R). Primarily, it was realized that major midbrain complexes such as the substantia nigra pars compacta (SNpc) and ventral tegmental area (VTA) are dopaminergic in nature. This important characteristic implies that these areas may be the precursors to neural and behavioral dysfunction related disease since they are a potential area for DA dysregulation. Additionally, it was found that even though different regions in the dorsal striatum receive dopaminergic inputs from distinct SNPc and VTA populations, they do in fact overlap with each other. This intertwined nature suggests that both behavioral pathways result in similar DA functions of processing and movement, also presenting itself as a location of future study for DA analysis endeavors. 

Ultimately, by examining the modulation factors of DA throughout the CNS, researchers can apply their synthesized information to medical treatment. Since it can be concluded that the degeneration of the SNpc neurons in the dorsal striatum region causes the dysfunction of dopamine associated with Parkinson’s, diagnosis of this particularly presenting malady can be streamlined. 

Works Cited:

[1] Q. Xiong, et al., Integrating the roles of midbrain dopamine circuits in behavior and neuropsychiatric disease. Biomedicines 9, 647-671 (2021). doi: 10.3390/biomedicines9060647.

[2] Image retrieved from:


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s