14 July 2015

Learning Impacts How Brain Processes Visualisation

In a University of California, a research team reports that in mouse models, the brain significantly changed its visual cortex operation modes by implementing top-down processes during learning. They 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.  Top-down inputs interact with specific neuron types in the visual cortex to modulate its operation modes. 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.


Researchers looked at activity in excitatory neurons and somatostatin-expressing inhibitory neurons in the visual cortex and top-down inputs from the retrosplenial cortex (RSC) during associative learning to see how these affected the top-down and bottom-up processing—when perception begins with the senses. The findings indicate that intricate interactions of various circuit components effectively change the balance of top-down and bottom-up processing, with learning enhancing the contribution of top-down control. These 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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