Dopamine is a familiar term to anyone who has enjoyed a bite of chocolate or glanced at each blinking notification on their phone.
However, dopamine is not the only thing that does this. This chemical neurotransmitter is also a key component of the prefrontal cortex, which controls higher brain functions such as paying attention, staying focused, and making decisions.
Research in rodents now shows that dopamine can alter the function and structure of the prefrontal cortex. A study published in The Journal Cell ReportsResearchers discovered that dopamine has no effect on individual cells. Instead, dopamine generates sustained activity within the prefrontal cortical cortex, which can last for up to 20 min.
“Ensembled brain cell activity can have a greater effect than individual neurons activity,” said Bita Moghaddam (Ph.D.), senior author and chair of behavioral neuroscience at OHSU School of Medicine.
Dopamine initiated a coordinated ensemble activity that lasted many minutes after it was released.
Moghaddam suggested that “this may provide a mechanism where dopamine support complex functions that need to be sustained such as motivation, attention to complete tasks, and so on.”
Optogenetic methods were used to stimulate dopamine neurons with light in rodents’ brains. Researchers then recorded the response in the prefrontal cortice. They detected weak signals among individual cells. However, a computational analysis detected multiple forms coordinated activity among cells in prefrontal cortex. This coordination lasted several hours after the initial burst.
The study found that dopamine cells also increase brain oscillations at the gamma frequency, which is in addition to its effect on ensemble activity. Although brain oscillation disruptions at this high frequency have been linked to ADHD and schizophrenia, the reason for this disruption is not yet known.
The discovery that dopamine plays a role in brain function provides new insights. Dopamine is found in the prefrontal cortex, which plays a major role in high-order cognition. This includes attention and behavioral flexibility. It’s also implicated in motivational and cognitive deficits of brain illnesses such as schizophrenia, addiction and attention-deficit/hyperactivity disorder.
Moghaddam stated that this could explain why sustained attention requires dopamine. “It can help explain how ADHD, where dopamine is deficient, affects not just one neuron but the entire brain.”
The National Institute of Mental Health granted grant MH48404 to support the study.
Materials provided by Oregon Health & Science University. Note: Content may be edited to improve style and length.