A new research has revealed that our brain accumulates evidence when faced with a choice and triggers an action once that evidence reaches a tipping point.
"Psychological models of decision-making explain that humans gradually accumulate evidence for a particular choice over time, and execute that choice when evidence reaches a critical level," said Braden Purcell, lead author of the study.
"However, until recently there was little understanding of how this might actually be implemented in the brain.
"We found that certain neurons seem to represent the accumulation of evidence to a threshold and others represent the evidence itself, and that these two types of neurons interact to drive decision-making," he added.
The researchers presented monkeys with a simple visual task of finding a target on a screen that also included distracting items. The researchers found that neurons processing visual information from the screen fed that information to the neurons responsible for movement.
These movement neurons served as gatekeepers, suppressing action until the information they received from the visual neurons was sufficiently clear. When that occurred, the movement neurons then proceeded to trigger the chosen movement.
The researchers also found that the movement neurons mediated a competition between what was being seen-in this case, the target and distracting items-and ensured that the decision was made to look to the proper item.
The findings offer potential insights into some psychological disorders.
"Impairments in decision-making are at the core of a variety of psychological and neurological impairments. This work may help us to understand why these deficits occur at a neurobiological level," said Purcell.
An important piece of this research is the novel model the researchers used in the study. The new model combined a mathematical prediction of what they thought would transpire with actual data about what the neurons were doing.
"In our work, rather than coming up with a mathematical expression for the inputs to the neural decision process, we defined those inputs with actual recordings from neurons. This hybrid model predicts both where and when the eyes move, and variability in the timing of those movements," said Thomas Palmeri, a co-author of the study. (ANI)
The research was published in the Psychological Review.