Our most complex organ, the brain, is a puzzle that scientists are still trying to piece together. Here at The Optimist Daily we like to keep our readers up to date with the latest discoveries on the neurological front, like pinpointing the singing regions of the brain or how zebrafish brains helped us understand how memories are imprinted.
This time we want to report an interesting finding from the Massachusetts Institute of Technology (MIT) that has gotten us one step closer to understanding how we make decisions.
How do you measure decision making?
As making a decision is neurologically complicated with many factors to be considered, an experiment had to be set up using mice that created a straightforward situation, simplifying the experiment as much as possible. The creatures were faced with a choice of turning a wheel either left or right: in one way they received a reward of sugary water and in one way they were confronted with a puff of air.
The mice soon learned to adjust their behavior to maximize their rewards, turning the wheel in the direction which landed them with tasty sugar water. After a while, the scientists changed which direction resulted in which outcome to see how the animal behavior would adapt. This procedure allowed a peek into what regions of the brain drive this decision-making process.
What region of the brain drives decisions?
Through recording neuronal activity, the team was able to identify a group of cells in the striatum that encodes this process. It was previously known that this region played a role in making decisions and evaluating outcomes, sending these signals to other parts of the brain like dopamine-producing regions to learn if it led to a positive or negative outcome. However, exactly how and where it did this was a mystery.
Specific neuronal cells became lively when a decision-making situation arose. The strongest signals in this region arose when an opposite outcome than what was expected played out, acting as “error signals” to alarm the brain to change its behavior. The researchers believe that this aids the brain in adapting to changing circumstances.
Why is this research important?
Impaired decision-making ability is a feature of mental illnesses, especially anxiety, depression, OCD, and addiction where people become impulsive or paralyzed with indecision. Here it is thought that decision error signals get mixed up with positive ones and the brain’s ability to make distinctions in a regular way is impaired.
This research, published in Nature Communications, pinpoints where decision making regions are and how they operate, opening up a whole new scope of behavioral therapy and targeted treatment to help with these symptoms.
Source study: Nature Communications – Multiplexed action-outcome representation by striatal striosome-matrix compartments detected with a mouse cost-benefit foraging task