How dopamine drives brain activity
Dopamine is a neurotransmitter involved in many aspects of human functioning, from behavior to cognition, from movement to motivation, from sleep to mood.
Advertising message Dopamine is an endogenous neurotransmitter belonging to the catecholamine family; it is produced in various brain areas, including the substantia nigra and the ventral tegmental area (ATV); however, we also find it in other brain areas, such as in the basal ganglia and in the nucleus accumbens.
The functions of dopamine are many, in fact it affects: behavior, voluntary movement, cognition, motivation, sleep and mood. Its action also spills over the sympathetic nervous system, causing the heart rate to accelerate and the blood pressure to rise (Wise, 2004).
Dopamine is particularly involved in the reward system, in fact, all the stimuli that produce motivation and reward (such as food, water, sex and drugs) cause the release of dopamine by the nucleus accumbens.
Given the numerous functions that the aforementioned neurotransmitter has, the drugs that inhibit or increase the production of dopamine are many and used for the most disparate pathologies, from Parkinson’s, to the treatment of depression and psychotic disorders (Seeman, 1980).
A study published on April 1, 2020 in the journal Nature, discovered how dopamine released deep into the brain affects both nearby and distant brain regions; in fact, prior to this research, the way in which dopamine influenced neuronal activity throughout the brain was unknown. Using a new and special magnetic resonance imaging, capable of tracking dopamine, the researchers observed that dopamine mainly affects its two brain areas: the motor cortex and the insular cortex. The latter is particularly involved in the regulation of cognitive functions related to the perception of the state of one’s internal body (enteroception) (Li & Jasanoff, 2020).
Researchers began to analyze how dopamine released in the rat striatum affected neural function, both locally and in other regions of the brain.
Advertising message First, they injected sensors that track dopamine (visible with the magnetic resonance cited above) in the striatum, which is located deep in the brain and plays an important role in controlling movement (Li & Jasanoff, 2020). They later electrically stimulated a part of the brain called the lateral hypothalamus, the latter being an experimental technique commonly used to reward behavior and induce the brain to produce dopamine. At this point, the researchers used their dopamine sensor to measure its levels across the striatum. In addition, they also performed traditional magnetic resonance imaging to measure neural activity in each part of the striatum (Li & Jasanoff, 2020). To their surprise, they found that high concentrations of dopamine did not make neurons more active. However, higher dopamine levels kept neurons active for a longer period of time, they also observed that the areas of the brain most affected by dopamine were the motor cortex and the insular cortex (Li & Jasanoff, 2020).