AsianScientist (Feb. 4, 2019) – Researchers from Singapore and South Korea have uncovered a brain pathway that regulates impulsive behaviors. Their findings are published in the Proceedings of the National Academy of Sciences.
Behavior is controlled by tightly-regulated chemical signals, or neurotransmitters, in the brain. Imbalances in the amount or proportions of neurotransmitters, or their location of expression in specific brain regions, can result in pathological impulses that are detrimental to quality of life.
In the present study, researchers led by Professor George Augustine from Nanyang Technological University, Singapore, discovered that impulsive behavior is triggered when the neurotransmitter dopamine signals to an unexpected area of the brain.
To trace the pathway dopamine takes to produce an impulsive action, Augustine and his team used mice in which a specific set of dopamine receptors (D2 receptors) had been genetically removed. Effectively, the brains of these mice were unable to detect native dopamine signals.
However, when the researchers artificially activated these receptors in specific parts of the brain, the mice displayed impulsive behavior when the signal was picked up by the amygdala, an almond-shaped structure deep in the brain.
The researchers were surprised to find that the amygdala’s dopamine receptors in turn passed on the ‘dopamine baton’ to neurons that connect it with the bed nucleus of the stria terminalis (BNST), a brain area not previously known to be involved in the pathway driving impulsive behavior.
“We have shown for the first time that impulsive behavior in mice is only triggered when dopamine signals are received and passed on to an unexpected part of the brain—from the amygdala to the BNST,” said Augustine.
“This research shows that the amygdala serves as a key staging post in the dopamine pathway that triggers impulsive behavior and confirms the role dopamine plays in regulating impulsivity,” he added.
These findings could have implications in the treatment of neuropsychiatric disorders, the researchers said.
“This new finding potentially could usher in novel pharmacological treatments that specifically target the dopamine D2 receptors located in the central amygdala and the BNST region, bringing about reductions in impulsivity and impulsive behaviors commonly seen in wide-ranging psychiatric conditions and disorders including conduct, anti-social and impulsive-control disorders,” said Associate Professor Ong Say How, senior consultant and chief of the Department of Developmental Psychiatry at the Institute of Mental Health Singapore, who was not involved in the research.
The article can be found at: Kim et al. (2018) Dopamine D2 Receptor-mediated Circuit From the Central Amygdala to the Bed Nucleus of the Stria Terminalis Regulates Impulsive Behavior.
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Source: Nanyang Technological University; Photo: Shutterstock.
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