A national team of researchers has identified a circuit in the brain that appears to regulate impulse control and be associated with psychiatric disorders ranging from overeating to drug abuse.
Behavioral impulsivity is common in various metabolic and psychiatric disorders such as attention-deficit hyperactivity disorder, excessive gambling, excessive food intake, weight gain, and obesity. Studies have indicated that melanin-concentrating hormone (MCH), is signaled by brain cells in the hypothalamus area of the brain and that it is linked to appetite for food and drugs, but it has remained unclear how it affects impulse control.
This study looked at specific brain connections that keep impulsivity in check and found that the connections that regulate hunger and food motivation are separate from those that control impulsivity. They lowered and raised the levels of MCH in rats’ brains to see how it would affect their impulsivity.
The researchers found that when the MCH levels went up, the rats were more impulsive. Yet they also noticed that if they were decreased, they were even more impulsive.
The scientists performed anatomical brain scans and were able to identify a neural pathway for impulse control in the hypothalamus. In this area, neurons signal MCH to other neurons in the hippocampus, an area of the brain associated with emotions and inhibition control.
The next step is for researchers to map the connection between this impulse control circuit and the brain’s rewards system. This could lead to better treatments for those with disorders that have an impulsivity component.