Summary: According to a new study, dopamine increases responses to both pleasurable and stressful stimuli. The findings may have implications for mental health disorder and addiction treatment.
The Vanderbilt University is the source.
Dopamine levels increase not only in response to pleasurable stimuli, but also in response to stressful stimuli, potentially rewriting the history of the feel-good hormone, a crucial mediator of numerous psychiatric disorders. This discovery calls for a reconsideration of the treatment of psychiatric disorders and addiction.
Erin Calipari, an assistant professor of pharmacology, and Munir Gunes Kutlu, a postdoctoral fellow in Calipari’s laboratory, directed this study.
Dopamine is frequently referred to as a pleasure or reward molecule in the media, according to Calipari, who is also a faculty member at the Vanderbilt Brain Institute and the Center for Addiction Research.
In the scientific community, research has revealed that the role of dopamine in learning and memory is more nuanced, but we lacked a complete and accurate theory to explain what dopamine does in the brain.
The prevalent model, known as the reward prediction error theory, is predicated on the notion that dopamine signals predictions regarding the timing of rewards. This theory proposes that dopamine is a recorder of every mistake we make when seeking rewards. Calipari stated that the authors demonstrate that RPE is only accurate in a subset of learning scenarios by demonstrating that, while rewards increase dopamine, so do stressful stimuli.
Then, we demonstrate that dopamine is not a reward molecule. It helps encode information about all types of significant and relevant events, regardless of whether they are positive or negative, and drives adaptive behavior.
Lin Tian, professor and vice chair of biochemistry and molecular medicine at UC Davis, collaborated with the researchers to study an unprecedented diversity of neurobehavioral processes related to dopamine release using cutting-edge technology.
The authors analyzed the data using machine learning, computational modeling, and optogenetic manipulations, which use light to control the activity of genetically modified neurons.
The investigation established a novel computational model of behavior that accurately predicts the behavioral effects of optogenetic perturbations of dopamine release. Calipari concluded that this study replaces our current understanding with a formalized theory and necessitates a revision of dopamine in the central nervous system textbook information.
Why It Is Vital
All addictive substances increase dopamine release in the brain, which has contributed to the perception of dopamine as a reward molecule. Danny Winder, director of the Vanderbilt Center for Addiction Research, remarked that models of addiction that rely on the dopamine/drug reward mentality must be reevaluated in light of these findings.
Calipari emphasizes that these data rewrite the established facts about dopamine, including what it encodes in the brain and how it influences behavior.
Dopamine is dysregulated in Parkinson’s disease and almost every psychiatric disorder, including addiction, anxiety and depression, schizophrenia, and others, she said. Understanding the significance of these dopamine deficits is crucial for comprehending patient symptoms and developing more effective treatments based on scientific evidence for these diseases.
What Follows?
Calipari stated that we intend to investigate how this novel framework fits into our understanding of drug addiction and how drugs alter dopamine signaling to disrupt behavior within this framework.
The majority of our understanding of the neurobiology of addiction is centered on dopamine and the dopaminergic network, as many therapeutic approaches designed to treat addiction target this neurotransmitter. However, modifying dopamine without a thorough understanding of what dopamine actually does may result in numerous unanticipated side effects and, more importantly, in ineffective treatment strategies.
This new understanding of what dopamine actually does will have a significant impact on many fields outside of neuroscience, as well as on human lives and health outcomes.
Funding
This research was supported by grants from the National Institutes of Health (DA048931, DA042111, KL2TR002245, GM07628, and DA045103) as well as the Vanderbilt University Medical Center Faculty Research Scholar Award, the Pfeil Foundation, the Brain and Behavior Research Foundation, the Whitehall Foundation, and the Edward Mallinckrodt, Jr. Foundation.
NEWS REGARDING DOPAMINE RESEARCH
Written by Marissa Shapiro The Vanderbilt University is the source. Contact: Marissa Shapiro Vanderbilt University The image is within the public domain.
Original Research: Confidential. Erin Calipari et al. discovered that dopamine release in the nucleus accumbens core signals perceived salience. Modern Biology
Abstract
Dopamine release in the core of the nucleus accumbens indicates perceived salience
A large body of work has aimed to define the precise information encoded by dopaminergic projections innervating the nucleus accumbens (NAc) (NAc). Dopamine updates associations between rewards and predictive cues by encoding perceived errors between predictions and outcomes, as per the reward prediction error (RPE) theory. However, RPE cannot describe multiple phenomena to which dopamine is inextricably linked, such as aversive and neutral stimulus-driven behavior.
Combining a series of behavioral tasks with direct, subsecond dopamine monitoring in the NAc of mice, machine learning, computational modeling, and optogenetic manipulations, we were able to characterize behavior and related dopamine release patterns across multiple contingencies reinforced by differentially valenced outcomes.
We demonstrate that dopamine release only conforms to RPE predictions in a subset of learning scenarios, whereas it is consistent with valence-independent perceived saliency encoding across conditions. We provide an extended, comprehensive framework for the role of accumbal dopamine release in behavioral regulation.
Conclusion
A new study finds dopamine increases responses to stressful stimuli, not just pleasurable ones. The findings could have implications for the treatment of mental health disorders and addiction.
