Learning Enhances Top-down Processing of Vision

From the smell of flowers to the taste of wine, our perception is strongly influenced by prior knowledge and expectations (so called top-down control) developed through learning. How is this learning-related change in perception mediated by brain circuits? This study reveals how the mouse brain changes its operation modes to implement these 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 to activate the visual cortex. Top-down inputs interact with specific neuron types in the visual cortex to modulate its operation modes. 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 generates abnormal perception.