It is believed by scientists that they have located a point deep in the brain that links an external trigger to binge-eating or drug-seeking behavior. We all have that “binge” eating that we would like NOT TO DO. Rats that had once responded excitedly and quickly to cues for sugar (like binge-eating) responded with less motivation and urgency when scientists switched off certain brain cells in that location. This discovery could lead to new ways to help reduce addictive behavior in people.
The findings were reported in the journal Neuron according to Dr. Jocelyn M. Richard, lead author who researches psychological and brain sciences at Johns Hopkins University in Baltimore.
Anything from a glimpse of powder that looks like cocaine or the jingle of an ice cream truck can trigger a relapse or binge eating as an external cue.
This shows a connection between environmental stimuli and the urge for food or drugs. This brain area focused on by the study is called the ventral pallidum (VP) and is a structure within the basal ganglia (a collection of brain cell clusters located deep beneath the cerebral cortex, the outer layer of the brain that is often referred to as gray matter).
The VP is often thought to be involved in reward-seeking, however very little is known about its role in triggering behavior in response to incentive cues. The team trained rats to learn that if they pushed a lever when they heard a particular sound, they would be rewarded with a drink of sugar water. They then got the rats to respond to the triggers while they monitored neuron activity within their VP areas.
Many more neurons became active than anticipated, and were quite vigorous. As the rats heard the cues they then responded. It was also noted that the stronger the neuron activity, the more rapidly the rats responded and sought their reward. It could even be predicted how fast the rats would move toward their reward by observing the size of the neuron responses to the cue. This was a surprise to the scientists to see such a high number of neurons showing such a big increase in activity when the rats heard the sound played.
The scientists also used optogenetics to temporarily turn off the VP neurons when the rats were exposed to the sound cues. This is a method where animals like rats and mice are genetically engineered to have brain cells that can be selectively switched on or off using light pulses. Researchers found that the rats were less likely to pull the levers to get the sugar water when they switched the VP neurons off. Then when the rats did pull the levers it was much more slowly.
It is suggested that the findings could lead to treatments that help people to moderate addictive behavior by toning down or calming brain reactions to the relevant triggers. The object is to tone down the exaggerated motivation for reward, not to make it so people don’t want rewards. I look forward to rewarding myself from time to time…. don’t take that chocolate away from me! Rewards work great with the kids, too!