Imbalance in the activation of two brain areas, the ventral striatum (VS on vertical scale) and the amygdala, predicts problem drinking in university students who are dealing with stress. The same two brain areas also predict the number of new sexual partners a person will have several months after his or her brain scan….the reward-seeking ventral striatum and the threat-assessing amygdala.
…low ventral striatum and high amygdala activity—predicted problem drinking in response to stress both at the time of the scan and three months after.
“The key is that these are patterns present before problems emerge,” especially in response to stress, says Ahmad Hariri. “If we know this about an individual, we can anticipate the problems and anticipate what the nature of those problems will be. This knowledge brings us one step closer to preventing the problems altogether.”
Brain imaging may be able to predict how likely young adults are to develop problem drinking or to engage in risky sexual behavior in response to stress.
“By knowing the biology that predicts risk, we hope to eventually change the biology—or at least meet that biology with other forces to stem the risk,”
“We now have these two distinct profiles of risk that, in general, reflect imbalance in the function of typically complementary brain areas,” Hariri says. “If you have high activity in both areas, no problem. If you have low activity in both areas, no problem. It’s when they’re out of whack that individuals may have problems with drinking.”
Interestingly, people with the two different risk profiles may drink for different reasons.
– those with high ventral striatum activity may be motivated to drink because they are impulsive; combined with a lower danger signal coming from the amygdala, they may be less inclined to reign in their behavior.
– In contrast, the participants with low ventral striatum activity usually have lower mood, and an overactive amygdala may make them more sensitive to stress, so they might drink as a coping mechanism.
Balance in the activity of the ventral striatum and the amygdala also predicts sexual behavior, according to the second study, which appears in the Journal of Neuroscience.
– For men, the same pattern of brain activity linked to problem drinking—high ventral striatum and low amygdala activity—was associated with a greater number of sexual partners compared to those men with more balanced activity of the two brain areas.
– for more sexually active women was different: they had higher-than-normal activity in both the ventral striatum and the amygdala—indicating both high reward and high threat.
In women, amygdala activity might be driving general awareness, arousal, and responsiveness which, when combined with strong reward-related activity in the ventral striatum, leads to a greater number of partners. In contrast, in men, the amygdala signal could be more focused on detecting danger