Brain regions recognize faces all at once, not in steps
Neuroscientists have long assumed the brain processes visual information like an assembly line: from back to front, from simple to complex. New research with electrodes placed directly inside human brains puts that model into question.
Researchers measured brain activity in 140 people viewing images of faces. They used direct electrophysiological recordings via implanted electrodes at more than 11,000 measurement sites in the visual cortex, specifically the ventral occipito-temporal cortex (VOTC), the brain region responsible for recognising visual objects.
Simultaneous, not sequential
What the researchers found departs from the classical picture. There is a gradient from back to front in how specifically brain regions respond to faces. But the activity itself occurs in all regions almost simultaneously, between roughly 100 and 450 milliseconds after seeing a face. Not one region first and then the next.
That suggests visual recognition in the brain is less hierarchically organised than previously thought. The regions work in parallel, not as sequential steps in a chain. The study was published in the journal eLife.
What this means for understanding brain aging
This research primarily concerns healthy brain function. But the findings are indirectly relevant to aging. As the brain grows older, coordination between brain regions often declines. If visual recognition depends on parallel collaboration, disruption of that synchrony may contribute to cognitive decline.
The study reformulates a fundamental model of how the human brain sees and recognises. That has implications for how we understand brain disorders and cognitive aging, though those connections remain speculative at this stage.
Search terms: visual cortex parallel processing, face recognition electrophysiology, occipito-temporal cortex brain organisation