Serotonin is essential for the regulation of patience

Delayed satisfaction is essential to human survival. This reduces the urge to take immediate and satisfying actions to earn rewards later. It’s an important human cognitive strategy, but little is known about how patience is regulated in the brain.

Image credit: OIST

Previous studies have suggested a role for serotonin, but have not revealed how it interacts with different brain structures to promote patience.Well, a new study done in Okinawa Institute of Science and Technology Graduate University (OIST), Japan has shown that serotonin release in the orbitofrontal cortex and medial prefrontal cortex is essential for the regulation of patience.

Effects of serotonin on different brain regions

Serotonin has been the focus of psychological research for decades. Much is understood about how neurotransmitters affect key factors that regulate human function, such as sleep and wake cycles, appetite, and even mood. It is also associated with mental disorders such as depression.

Previous studies have also hinted at its role in regulating patience. Earlier rat models have shown that serotonin regulates impulse-related behaviors, at least in part, and its effects on the basal ganglia circuit may be important for this.

Following this previous study, the OIST team designed a study to uncover the neural correlation of patience and to understand how serotonin affects it. The team bred mice genetically engineered to have neurons that release serotonin in response to light stimuli.

Results of a study published in the journal this month Science Advances, Stimulating these neurons has shown that mice spend more time waiting for food. This effect was most pronounced when you were more likely to receive a reward and you were uncertain when to receive it.

Scientists have investigated specific areas of the brain that they believe can affect delayed satisfaction. They implanted optical fibers in the nucleus accumbens, orbitofrontal cortex, or medial prefrontal cortex, as well as in the dorsal raphe nucleus.

Role of the orbitofrontal cortex and medial prefrontal cortex

No effect of stimulating serotonin-releasing nerve fibers in the nucleus accumbens was observed, suggesting that it is not involved in the regulation of patience. On the other hand, by stimulating serotonin-releasing nerve fibers in the orbitofrontal cortex and medial prefrontal cortex, researchers have observed that mice can wait longer. Proposing both of these areas is important in adjusting patience.

Release of serotonin in the orbitofrontal cortex had a similar effect to release of serotonin in the dorsal raphe nucleus. Activation of serotonin in both of these areas was associated with delayed satisfaction in situations where reward times were fixed or uncertain, but with uncertainties it produced stronger results. I did.

Subtle differences were observed in the medial prefrontal cortex, and researchers saw that increased patience was triggered only when the timing of rewards changed.

Team results show that each of these areas contributes individually to the overall waiting behavior of the mouse. To investigate this further, computational models have been developed to gain deeper insights. Models have found that the release of serotonin in these brain regions enhances the mouse’s belief that certain trials will be rewarded and encourages them to wait longer.

Improvement of depression treatment

Overall, this study is important in expanding our knowledge of how different brain regions and networks are affected by serotonin and then regulate patience. A more complete understanding of how serotonin affects different areas of the brain is to improve certain drugs, such as selective serotonin reuptake inhibitors (SSRIs) used to treat depression. Is essential to.