Summary: For the first time, researchers have directly observed dopamine release in the human brain during moments of cognitive flexibility. Using PET imaging, they found that dopamine levels spike in the ventromedial prefrontal cortex when people switch between tasks — and the more dopamine released, the more efficiently they adapted.
This confirms a biochemical link between dopamine and the brain’s ability to adjust behavior in response to changing demands. The discovery may help refine treatments for disorders like Parkinson’s, depression, ADHD, and schizophrenia, which often impair flexible thinking.
Key Facts:
- Dopamine & Adaptability: Higher dopamine release correlates with better task switching.
- Brain Region Identified: PET scans showed dopamine activity in the ventromedial prefrontal cortex.
- Clinical Relevance: Findings may guide treatments for psychiatric and neurological disorders with impaired cognitive flexibility.
Source: SNMMI
For the first time, scientists have confirmed a neurobiochemical link between dopamine and cognitive flexibility, according to new research published in the March issue of The Journal of Nuclear Medicine.
PET imaging shows that the brain increases dopamine production when completing cognitively demanding tasks, and that the more dopamine released, the more efficiently the tasks are completed.
Armed with this information, physicians may soon be able to develop more precise treatment strategies for neurological and psychiatric disorders.
Cognitive flexibility is the ability to adapt one’s thinking and behavior appropriately to a changing environment and is considered an aspect of executive function. Cognitive flexibility differs among people and is reported to be impaired in several psychiatric and neurologic disorders, such as depression, posttraumatic stress disorder, addiction, anxiety disorder, schizophrenia, Parkinson’s disease, and attention-deficit/hyperactivity disorder.
“At the neurotransmitter level, the dopamine system has been linked to cognitive flexibility. A direct neurochemical response to cognitive flexibility, however, has yet to be shown,” said Isabelle Miederer, PhD, associate professor in experimental nuclear medicine in the department of nuclear medicine at University Medical Center Mainz, Germany.
“In our study, we sought to examine the release of dopamine in real-time by performing PET scans while individuals completed behavioral flexibility tasks.”
Eighteen participants were scanned with the D2/3 receptor ligand 18F-fallypride in a two-part block study design. In the first part, participants performed two tasks consecutively on a computer screen without rule switching while undergoing PET imaging.
In the second part of the PET scan, participants had to switch flexibly between two task rules. Dopamine release was calculated using the linearized simplified reference region model which compares the two task blocks with each other.
PET imaging analysis showed a displacement of 18F-fallypride in the ventromedial prefrontal cortex during the task switching (higher cognitive demand) part of the study, which is assumed to be the release of dopamine. Results also showed that the greater dopamine release, the more efficient participants were in switching between tasks.
“The present findings emphasize the significance of dopamine in cognitive flexibility,” said Mathias Schreckenberger, MD, head of the department of nuclear medicine at University Medical Center Mainz.
“They are consistent with the results of previous clinical studies indicating that dopamine deficiency in disorders such as Parkinson’s disease may cause behavioral deficits in cognitive flexibility.”
“Looking forward, it is expected that the results of the study will contribute to a better understanding of the neurochemical mechanisms underlying cognitive flexibility and thus facilitate the development of treatment strategies to improve flexibility in neurological and psychiatric disorders,” he continued.
About this dopamine and neuroscience research news
Author: Rebecca Maxey
Source: SNMMI
Contact: Rebecca Maxey – SNMMI
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Dopaminergic Mechanisms of Cognitive Flexibility: An [18F]Fallypride PET Study” by Isabelle Miederer et al. Journal of Nuclear Medicine
Abstract
Dopaminergic Mechanisms of Cognitive Flexibility: An [18F]Fallypride PET Study
Cognitive flexibility is the ability to appropriately adapt one’s thinking and behavior to changing environmental demands and is conceptualized as an aspect of executive function. The dopamine system has been implicated in cognitive flexibility; however, a direct, that is, neurochemical, link to cognitive flexibility has not been shown yet.
The aim of this study was, therefore, to investigate how cognitive flexibility is mediated by dopaminergic signaling in the ventromedial prefrontal cortex (vmPFC).
Methods: Eighteen participants were measured in a PET study with 174 ± 12 MBq of the D2/3 receptor ligand [18F]fallypride in a block design with 2 parts. While participants processed 2 tasks sequentially without rule switching on a computer screen in the first part of the PET scan, they had to flexibly switch between the 2 task rules after 100 min after injection in the second part.
Dopamine release (γ) was quantified using the linearized simplified reference region model contrasting the 2 task blocks (switching vs. no-switching/baseline).
Results: The statistical analysis of the parametric γ-images showed that the increased cognitive demand during task switching induced a displacement of the D2/3 receptor ligand [18F]fallypride in the vmPFC (maximum T value = 13.8; cluster size: 528 voxels; familywise error rate–corrected P < 0.001; mean γ = 0.022 ± 0.006 min−1). Furthermore, a correlation between behavioral switch costs and vmPFC [18F]fallypride displacement suggested that participants showing greater dopamine release were more efficient in task switching.
Conclusion: To our knowledge, this is the first experimental PET study to show direct involvement of dopamine in the vmPFC in a task-switching paradigm, confirming model assumptions about the neurochemical basis of cognitive flexibility.
