Ever wonder why our New Year's resolutions typically disappear from our list of goals shortly after we make them? New research from Duke University reveals that habits leave lasting marks on circuits in your brain, making it more difficult to fend off our cravings.
"One day, we may be able to target these circuits in people to help promote habits that we want and kick out those that we don't want," Nicole Calakos, the study's senior investigator, said in a press release.
The team trained healthy mice to pick up sugar habits by giving them the ability to receive tiny sweets by pressing a lever. Each mouse had a habit of differing severity and those that were hooked kept pressing the lever even after the treats were not given to them. Afterwards, the researchers compared the brains of mice addicted to sugar and compared them those from a control group who were not addicted; in particular, the team studied basal ganglia activity, a network of brain regions that governs compulsive behaviors and addictions.
The results showed that in mice that had developed a sugar habit, the "stop" and "go" signals – which are the two types of pathways in the basal ganglia – were more active. Furthermore, the timing of activation in the two pathways was altered in mice with a sugar habit so that the go pathway was activated before the stop pathway.
"The go pathway's head start makes sense," said Calakos. "It could prime the animal to be more likely to engage in the behavior."
Calakos and his team also tried to break the mices' habits by rewarding them if they stopped pressing the lever and found that mice that were successful had weaker go cells.
The results could help researchers better understand addiction, although targeting it with medication will be difficult due to the basal ganglia's involvement in a variety of functions.
The findings were published in the Jan. 21 issue of Neuron.
