Study Reveals Manipulation of Dopamine in Mice

The Role of Dopamine

A recent study has highlighted that dopamine, often referred to as the “feel good” hormone, can be influenced and manipulated intentionally. This neurotransmitter plays a crucial role in our brain’s reward system, eliciting feelings of joy, such as the excitement of hearing an ice cream truck or savoring a delightful sip of wine after achieving a significant accomplishment.

Understanding Dopamine’s Function

Dopamine functions by transmitting signals between brain cells and is present throughout the brain. It is essential in affecting cognitive responses and their processing.

Research Findings from UC San Diego

Researchers from the University of California, San Diego, conducted a study published in the journal Current Biology, focusing on the less understood aspects of dopamine’s ability to generate spontaneous responses. The study demonstrated that mice could manipulate random dopamine impulses at will, rather than merely responding to these impulses in the context of pleasure or reward-based expectations.

Insights into Dopamine Impulses

A graduate student at UC San Diego discovered that the neocortex of mice experiences unpredictable dopamine impulses approximately every minute. Collaborating with researchers from the Icahn School of Medicine at Mount Sinai in New York, the team investigated whether mice were aware of their ability to regulate these impulses. Using various molecular and optical imaging techniques, they confirmed their hypothesis.

Experimental Setup and Results

The researchers devised a feedback mechanism where mice on a treadmill received rewards for demonstrating control over the spontaneous dopamine signals. The results indicated that the mice learned to anticipate and act upon some of these impulses. According to the researchers, “Critically, mice learned to reliably elicit dopamine impulses before receiving a reward. These effects reversed when the reward was removed.” They also suggested that these spontaneous dopamine impulses might play a significant role in behavioral planning.

Future Research Directions

This study opens new avenues for understanding brain dynamics related to dopamine responses. The researchers plan to investigate how unpredictable dopamine events may influence foraging behaviors, an essential aspect of seeking food, finding mates, and social interactions in new environments.

Conclusion and Acknowledgements

The researchers noted that their findings indicated dopamine invigorates rather than initiates motor behavior. Senior co-author David Kleinfeld, a professor in the Department of Physics and Section of Neurobiology, remarked, “This started as a serendipitous finding by a talented, and curious graduate student with intellectual support from a wonderful group of colleagues. As an unanticipated result, we spent many long days expanding on the original study and performing control experiments to verify the claims. These led to the current conclusions.”

References

Conrad Foo, Adrian Lozada, Johnatan Aljadeff, Yulong Li, Jing W. Wang, Paul A. Slesinger, David Kleinfeld. Reinforcement learning links spontaneous cortical dopamine impulses to reward. Current Biology, 2021; DOI: 10.1016/j.cub.2021.06.069
University of California – San Diego. (2021, July 23). ‘Feel good’ brain messenger can be willfully controlled, new study reveals: Neuroscientists show that mice can learn to manipulate random dopamine impulses for reward. ScienceDaily. www.sciencedaily.com/releases/2021/07/210723121512.htm
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