Making tough decisions could make or break the outcome of important events in your life. It is never easy having to choose between two options with both positive and negative add-ons. Drinking with your borderline alcoholic friend for the fourth time this week could turn out to be the night of your life, but it might lead to you filing for unemployment. Tough call.
Neuroscientists from the Massachusetts Institute of Technology (MIT) published a study that says that making decisions in a cost-benefit conflict, which is a situation where both outcomes could lead to both favorable and unfavorable results, is affected heavily by chronic stress.
During the study involving mice, they found that stressed animals were far likelier to choose high-risk, high-payoff options.
The researchers studied mice to understand the decision making in animals. The subjects were allowed to choose between go ing through a maze with reasonable lighting and diluted chocolate milk at the end or going through another maze that had harsh, annoying lights and concentrated chocolate milk at the end. The more concentrated the milk, the tastier the reward . reward.s means having to brave the bright lights.
When one particular group of these test mice were stressed, it immediately resulted in a dramatic change in the decision making. The team observed that the stressed mice were far more likely to choose the high-risk, high-reward situation, which in this case was the concentrated chocolate milk at the end of a bright and arduous pathway.
This study showed that the stress in mice can be directly linked to neurological disorders that affect people. People who suffer from addiction, depression and post-traumatic stress disorder will exhibit behavior that is often deemed erratic, risky and impulsive. The team says that the stress on the brain could be triggering it. People coming off addiction are often under tremendous mental and physical stress which could drive them to do erratic things.
The team could sucessfully link this behavior to impairments in a specific brain circuit that drove this risky behavior.
According to a release on MIT News, the team said that this circuit weighs the information about the good and bad aspects of choices and process this to make a decision. Normally, when the circuit is turned on, neurons of the prefrontal cortex activate certain neurons called high-firing interneurons, which then suppress striosome activity.
The team found that in stressed animals, the circuit works differently. The cortical neurons start fir ing too late which does not inhibit the striosomes on time. This causes them to be over excited during decision making , altering choice.
“Somehow this prior exposure to chronic stress controls the integration of good and bad,” Graybiel Friedman , lead author of the study sa id in the report . “It’s as though the animals had lost their ability to balance excitation and inhibition in order to settle on reasonable behavior.”
Once this shift occurs, it remains in effect for months, the researchers found , impacting decision making overtime which could causes major effects on a persons’ life.
However, they were able to restore normal decision making in the stressed mice by using optogenetics ; a process of controlling light to control neurons in the brain; to stimulate the high-firing interneurons, thereby suppressing the striosomes.
This showed the team that the prefronto-striosome circuit , which is the part affected by stress, is not damaged structurally after an episode of chronic stress and could be helped to restore normal decision making in patients with neurological disorder who exhibited erratic decision making.
“This state change could be reversible, and it’s possible in the future that you could target these interneurons and restore the excitation-inhibition balance,” Graybiel added .
Source : http://www.ibtimes.com/chronic-stress-drives-you-make-high-risk-decisions-mit-study-2616811644