A Yale study uncovers the effects of visual clutter on information flow in the brain, offering a new understanding of visual perception. Researchers explore how clutter disrupts neural pathways in the visual cortex.
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Whether we’re engrossed in our phones, reading a book or engaging with someone across the table, our focus is rarely isolated; it competes with numerous other objects or individuals in our peripheral vision. The impact of this visual “clutter” on brain processing has long been a gray area. Now, a new study by Yale researchers offers fresh insights into this phenomenon, revealing how clutter disrupts the flow of information in the brain.
Published in the journal Neuron, the study elucidates how clutter alters information flow in the brain and the crucial role of visual clutter’s location within our field of vision. This research advances our understanding of the neural foundations of perception and the visual cortex.
“Prior research has shown that visual clutter has an effect on the target of your perception, and to different degrees depending on where that clutter is with respect to where you’re currently looking,” co-senior author Anirvan Nandy, an assistant professor of neuroscience at the Yale School of Medicine (YSM), said in a news release. “So for example, if I’m asked to read the word ‘cat’ out of the corner of my eye, the letter ‘t’ will have a much greater effect than the letter ‘c’ in my inability to accurately identify the letter ‘a,’ even though ‘c’ and ‘t’ are equidistant from ‘a.’”
This phenomenon, known as “visual crowding,” explains why reading or identifying objects in the periphery remains challenging regardless of effort, added Nandy.
To explore what happens in the brain amid visual clutter, the research team trained macaque monkeys to fixate on the center of a screen while visual stimuli were presented both within and outside their receptive fields. They monitored neural activity in the primary visual cortex, the brain’s main conduit for processing visual information.
The results were revealing: while the location of clutter within the visual field did not significantly alter the order in which information was transmitted between neurons, it did impact the efficiency with which this information flowed.
“For example, visual clutter in one location would drive information in a particular layer of the primary visual cortex to a lesser extent than clutter in another location,” co-senior author Monika Jadi, an assistant professor of psychiatry at YSM, said in the news release.
Additionally, the researchers discovered a new, general property within the visual cortex.
Visual processing involves multiple brain areas working in sequence, each forwarding information to the next. Previously, it was known that complex computations within individual visual areas then transmit outputs to subsequent regions in the visual hierarchy.
The new study found that subunits within these larger areas also perform specialized computations, relaying some, but not all, of this information to neighboring subunits.
“When you’re driving, for instance, you may be looking at the car in front of you, but your attention could be focused on a car in the next lane as you try to determine if they’re about to merge,” added Nandy.
This insight bridges a knowledge gap between different fields studying vision, offering a more nuanced understanding of visual processing mechanisms.
Moving forward, the researchers aim to examine how visual clutter affects information transfer between brain regions and the role attention plays in this process.
“How does that attention compensate for the fact that while you don’t have the best resolution information, you’re still able to perceive that attended part of the visual space much better than where you’re actually looking?” Jadi added. “How does attention influence information flow in the cortex? That’s what we want to explore.”