Dartmouth College scientists recently identified the neurons in the brain that are involved in suppressing feelings of cravings and desire.

Researchers discovered that the stimulation of designer neural receptors can control cravings in the region of the brain where these cravings are triggered. The study will contribute in fighting against habitual human behavior such as overeating and addiction, they said.

The team explained that people are bombarded every day with cues in the form of advertisements. These cues garner people's attentions and influence them to buy rewards or products. This is the reward-cue phenomenon, and it can become appealing to consumers. For instance, when a person sees the McDonald's golden arch logo, chances are the image will influence the person to feel hungry when he really isn't and even though he hasn't seen food.

In a study issued in the European Journal of Neuroscience, the scientists examined this reward-cue phenomenon through sign-tracking as observed in rats. The reward for cues will be given whatever the rat's behavior was as a form of conditioning.

Stephen Chang, the study's lead author and a postdoctoral fellow, said that little is known about the brain circuitry underneath the transmitting of value in reward-cue relationships.

Chang said they were mostly concerned in whether the ventral pallidum, the region of the brain connected to reward processing, is also involved in sign-tracking.

The team's findings were the first to systematically show how the ventral pallidum contributes in the attribution of value cues for rewards. Chang explained that the ventral pallidum was only known to be an area for expressing behavioral motivations before. The study is also the first to show how designer neural receptors and designer drugs work together to change cues for food stimulation.

The methods of the study would have been impossible without the use of the new technology called DREADDs or Designer Receptors Exclusively Activated by Designer Drugs.

Researchers explained that the brain cells are filled with natural receptors similar to a molecular jigsaw puzzle that can be activated when another molecules fits like a missing piece. With DREADDs, engineered receptors are injected into the neurons through viruses. A synthetic drug can activate these engineered receptors. This can shut down neurons as some sort of remote control, they said.

The DREADDs technology allowed researchers to inactivate the ventral pallidum temporarily and repeatedly during tests in lab rats. These animals' reward-driven behaviors were blocked because of the technology.

Chang said that the study's findings have the potential to strip away value from cases such as addiction.

"The ventral pallidum is a novel target for such work," added Chang.