Echoes discovered in early visual brain areas play role in working memory

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Source: Science Centric

Vanderbilt University researchers have discovered that early visual areas, long believed to play no role in higher cognitive functions such as memory, retain information previously hidden from brain studies. The researchers made the discovery using a new technique for decoding data from functional magnetic resonance imaging or fMRI. The findings are a significant step forward in understanding how we perceive, process and remember visual information.

The results were published 18 February online by Nature.

'We discovered that early visual areas play an important role in visual working memory,' Frank Tong, co-author of the research and an associate professor of psychology at Vanderbilt, said. 'How do people maintain an active representation of what they have just seen moments ago? This has long been a conundrum in the literature.

'Before, we knew that early visual areas of the cerebral cortex that are the first to receive visual information were exquisitely tuned to process incoming visual signals from the eye, but not to store this information,' Tong said. 'We also knew that the higher-order brain areas responsible for memory lack the visual sensitivity of early brain areas, but somehow people are able to remember a visual pattern with remarkable precision for many seconds, actually, for as long as they keep thinking about that pattern. Our question was, where is this precise information being stored in the brain?

'Using a new technique to analyse fMRI data, we've found that the fine-scale activity patterns in early visual areas reveal a trace or something like an echo of the stimulus that the person is actively retaining, even though the overall activity in these areas is really weak after the stimulus is removed,' Tong continued

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