A study has found that people going through stressful circumstances usually make risky and abnormal decisions under chronic stress. Making decisions in this type of situation, known as a cost-benefit conflict, is dramatically affected by chronic stress. The study, published in the journal Cell, states that impairments of a specific brain circuit underlie this abnormal decision making and could further restore normal behaviour by manipulating this circuit. If a method for tuning this circuit in humans were developed, it could help patients with disorders such as depression, addiction, and anxiety, which often feature poor decision-making, the researchers noted. “We found a microcircuit of neurons in the striatum that we could manipulate to reverse the effects of stress on this type of decision making,” said Ann Graybiel, Professor at the Massachusetts Institute of Technology in Cambridge, the US. The researchers believe that this circuit integrates information about the good and bad aspects of possible choices, helping the brain to produce a decision. The team conducted a mice study, whereby rodents were allowed to choose between highly concentrated chocolate milk, which they like, under the presence of a bright light, which they don’t, and an option with dimmer light but weaker chocolate milk. Before experiencing stress, normal rats and mice chose to run towards the dimmer light and weaker chocolate milk about half the time. As the researchers gradually increased the concentration of chocolate milk in the dimmer side, the animals began choosing that side more frequently.