Past learning affects what we see: Study

Prior knowledge impacts how the brain processes what we see, says a new study.

The results support the long-standing theory that the brain does not faithfully represent the environment but rather attempts to predict it based upon prior information.

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From the smell of flowers to the taste of wine, our perception is strongly influenced by prior knowledge and expectations, a cognitive process known as top-down control.

The new research in mouse models found that the brain significantly changed its visual cortex operation modes by implementing top-down processes during learning.

"We found that when the mouse assigns a new meaning to a previously neutral visual stimulus, top-down control becomes much more influential in activating the visual cortex," said first author Hiroshi Makino, postdoctoral researcher at University of California, San Diego School of Medicine.

"Top-down inputs interact with specific neuron types in the visual cortex to modulate its operation modes," Makino said.

This cognitive process uses our thoughts and influences our senses. For example, when we see a word with missing letters, our brain is able to fill in the blank based on past experiences.

"In addition to revealing circuit mechanisms underlying these learning-related changes, our findings may have implications in understanding the pathophysiology of psychiatric diseases, such as schizophrenia, that generate abnormal perception," Makino added.

The study published in the online journal Nature Neuroscience.