Two Simon Fraser University psychologists have made a brain-related discovery that could revolutionize doctors’ perception and treatment of attention-deficit disorders.

This discovery opens up the possibility that environmental and/or genetic factors may hinder or suppress a specific brain activity that the researchers have identified as helping us prevent distraction.

The Journal of Neuroscience has just published a paper about the discovery by John McDonald, an associate professor of psychology and his doctoral student John Gaspar, who made the discovery during his master’s thesis research.

This is the first study to reveal our brains rely on an active suppression mechanism to avoid being distracted by salient irrelevant information when we want to focus on a particular item or task.

McDonald, a Canada Research Chair in Cognitive Neuroscience, and other scientists first discovered the existence of the specific neural index of suppression in his lab in 2009. But, until now, little was known about how it helps us ignore visual distractions.

“This is an important discovery for neuroscientists and psychologists because most contemporary ideas of attention highlight brain processes that are involved in picking out relevant objects from the visual field. It’s like finding Waldo in a Where’s Waldo illustration,” says Gaspar, the study’s lead author.

“Our results show clearly that this is only one part of the equation and that active suppression of the irrelevant objects is another important part.”

Given the proliferation of distracting consumer devices in our technology-driven, fast-paced society, the psychologists say their discovery could help scientists and health care professionals better treat individuals with distraction-related attentional deficits.

“Distraction is a leading cause of injury and death in driving and other high-stakes environments,” notes McDonald, the study’s senior author. “There are individual differences in the ability to deal with distraction. New electronic products are designed to grab attention. Suppressing such signals takes effort, and sometimes people can’t seem to do it.

“Moreover, disorders associated with attention deficits, such as ADHD and schizophrenia, may turn out to be due to difficulties in suppressing irrelevant objects rather than difficulty selecting relevant ones.”

The researchers are now turning their attention to understanding how we deal with distraction. They’re looking at when and why we can’t suppress potentially distracting objects, whether some of us are better at doing so and why that is the case.

“There’s evidence that attentional abilities decline with age and that women are better than men at certain visual attentional tasks,” says Gaspar, the study’s first author.

Notes about this neuropsychology research

The study was based on three experiments in which 47 students performed an attention-demanding visual search task. Their mean age was 21. The researchers studied their neural processes related to attention, distraction and suppression by recording electrical brain signals from sensors embedded in a cap they wore.

Contact: John Gaspar – Simon Fraser University

Source: Simon Fraser University press release

Image Source: The image is credited to Simon Fraser University and is adapted from the press release. The image is licensed Creative Commons Attribution 2.0 Generic

Original Research: Full open access research (PDF) for “Suppression of Salient Objects Prevents Distraction in Visual Search” by John M. Gaspar and John J. McDonald in Journal of Neuroscience. Published online April 16 2014 doi:10.1523/JNEUROSCI.4161-13.2014

Open Access Neuroscience Abstract

Suppression of Salient Objects Prevents Distraction in Visual Search

To find objects of interest in a cluttered and continually changing visual environment, humans must often ignore salient stimuli that are not currently relevant to the task at hand. Recent neuroimaging results indicate that the ability to prevent salience-driven distraction depends on the current level of attentional control activity in frontal cortex, but the specific mechanism by which this control activity

prevents salience-driven distraction is still poorly understood. Here, we asked whether salience-driven distraction is prevented by suppressing salient distractors or by preferentially up-weighting the relevant visual dimension. We found that salient distractors were suppressed even when they resided in the same feature dimension as the target (that is, when dimensional weighting was not a viable selection strategy). Our neurophysiological measure of suppression—the PDcomponent of the event-related potential—was associated

with variations in the amount of time it took to perform the search task: distractors triggered the PD on fast-response trials, but on slow-response trials they triggered activity associated with working memory representation instead. These results demonstrate that during search salience-driven distraction is mitigated by a suppressive mechanism that reduces the salience of potentially distracting visual objects.

“Suppression of Salient Objects Prevents Distraction in Visual Search” by John M. Gaspar and John J. McDonald in Journal of Neuroscience April 16 2014 doi:10.1523/JNEUROSCI.4161-13.2014

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