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As novel sights become familiar, different brain rhythms, neurons take over

As ‘visual recognition memory’ emerges in visual cortex, one circuit of inhibitory neurons supplants another and slower neural oscillations prevail
June 9, 2021
Side-by-side fields of green fluorescent cells

Researchers observed the activity of PV neurons (left) and SOM neurons (right) in the visual cortex to understand the emergence of visual recognition memory. Image credit: Daniel Montgomery, MIT Picower Institute.


To focus on what’s new, we disregard what’s not. A new study by researchers at MIT’s Picower Institute for Learning and Memory substantially advances understanding of how a mammalian brain enables this “visual recognition memory.”

Dismissing the things in a scene that have proven to be of no consequence is an essential function because it allows animals and people to quickly recognize the new things that need to be assessed, said Mark Bear, Picower Professor in the Department of Brain and Cognitive Sciences and senior author of the study in the Journal of Neuroscience.

In the new study led by graduate students Dustin Hayden and Daniel Montgomery, Bear’s lab shows that as novel visual patterns become familiar, the transition is marked by stark changes in the visual cortex. Gamma rhythms give way to lower frequency beta rhythms and the activity of PV neurons dies out in favor of a rise in activity by inhibitory somatostatin (SOM) expressing neurons.