Brain activity underlying focus and ignoring visual distractions discovered

New Delhi: Researchers have uncovered underlying brain mechanisms that help decide whether to focus visual attention on a rewarding task or an alluring distraction.

In the front part of the brain lies the lateral prefrontal cortex (LPFC), known to be responsible for motivation and rewards.

A pattern of coordinated activity called "beta bursts" in certain neurons in the LPFC appears to be key to suppressing visual distractions to focus attention on a goal-related task, the researchers at the University of Pennsylvania, US, discovered in animal models as they faced such an attentional conflict.

Understanding these mechanisms could help understand failures to do so in a range of cognitive and psychiatric disorders, including attention deficit disorder, schizophrenia, and obsessive-compulsive disorder, the researchers said.

"Our research suggests that while all brains have the ability to focus on a rewarding task and filter out distractions, some are better at it than others," said Bijan Pesaran, senior author of the study published in the journal Neuron.

In animal models, the neuroscientists found strong evidence of certain LPFC neurons, called the "visual-movement" neurons, being able to direct attention towards either the rewarding shape or the distracting one, as the models were being visually distracted while completing a task.

During periods of focus, these visual-movement neurons were observed to fire together at the same frequency, termed "beta bursts", helping the models to choose to ignore visual distractions to complete their task.

Further, the subjects in whom beta bursts occurred prior to being presented with visual distractions were more likely to ignore them than those in whom beta bursts were either weak or absent before being distracted, the scientists found.

"This suggests to us that the beta-bursts originate in a network of visual-movement neurons, and act as 'traffic directors' for the neurons that process different visual stimuli," said first author Agrita Dubey, a postdoctoral researcher in the Pesaran laboratory.

"It also suggests that focusing on a rewarding task takes a great deal of energy, and that it may be something that can be improved, especially in individuals with attention deficits," said Dubey.

Humans and other large mammals have "top-down" control, in which attention is directed towards a task with the intention of accomplishing a rewarding goal.

However, large mammals also possess a brain circuitry that automatically redirects their attention based on incoming sights and sounds and other striking sensory stimuli. This is known as "bottom-up" control, which is capable of causing distractions.