Dopamine Can be Willfully Controlled; New Study Reveals

July 4th, 2021

Dopamine, the brain’s feel-good messenger, is responsible for creating all the immersed happiness feelings after a successful chase at sports or hearing the sound of ice cream approaching. The chemical acts like a neurotransmitter related to rewards and pleasure of daily lives, involving multiple aspects of cognitive processing. The above has been revealed in the journal Current Biology, a research study conducted by the University of California, San Diego. The study also revealed that mice could willfully manipulate and control the random dopamine pulses for rewards.

The Researchers believe that spontaneous impulses of dopamine, the ‘feel-good chemical, also occur in the minds of mice, who can willfully control their dopamine pulses for rewards. The chemical has been studied extensively to understand its external cues or deterministic signals and aspects related to its spontaneous impulses.

The research study led by UC San Diego graduate student Conrad Foo found that the neocortex in mice is flooded with unpredictable impulses of dopamine that occur approximately once per minute. He worked with colleagues at UC San Diego (Department of Physics and Section of Neurobiology) and the Icahn School of Medicine at Mount Sinai in New York. In his research, Foo documented in the lab through molecular and optical imaging techniques to check whether these impulses are occurring.

To prove this, the team of researchers worked on a feedback scheme in which mice on a treadmill received a reward if they showed they could control the impromptu dopamine signals. The data obtained showed that the mice were aware of their dopamine impulses while learning to anticipate and volitionally act upon a portion of them.

"Critically, mice learned to elicit (dopamine) impulses before receiving a reward reliably," the researchers wrote in the paper. "These effects were reversed when the reward was removed. We posit that spontaneous dopamine impulses may serve as a salient cognitive event in behavioral planning."

According to researchers, the study adds a new dimension to the study of dopamine and brain dynamics. They are now planning to extend this research to explore if and how unpredictable dopamine events drive foraging, which is an essential aspect of seeking sustenance, finding a mate, and social behavior in colonizing new home bases.

"We further conjecture that an animal's sense of spontaneous dopamine impulses may motivate it to search and forage in the absence of known reward-predictive stimuli," the researchers noted.

In their efforts to control dopamine, the researchers clarified that dopamine appears to invigorate, rather than initiate, motor behavior.

"This started as a serendipitous finding by a talented, and curious, a graduate student with intellectual support from a wonderful group of colleagues," said senior study co-author David Kleinfeld, a professor in the Department of Physics (Division of Physical Sciences) and Section of Neurobiology (Division of Biological Sciences). "As an unanticipated result, we spent many long days expanding on the original study and, of course, performing control experiments to verify the claims. These led to the current conclusions."