Linking neural circuits to perception in mammalian visual cortex

Background: It is widely appreciated that the brain has a remarkable capacity to process incoming information. Research in my lab focuses on the visual system, using precisely controlled visual stimuli as inputs to gain insight into the computations the brain performs to produce perception and behavior. Although the eyes detect light, most of what is commonly thought of as vision actually arises from analyses performed by an interconnected network of brain areas called the geniculo-striate pathway. It has long been conjectured that within each brain area along this pathway visual signals are also shaped by specific connections between different types of brain cells (neurons) called local neural circuits. Technology to produce genetically modified laboratory mice has provided new tools to dissect the inter-areal networks and local neural circuits underlying vision. In particular, the targeted expression of optogenetic proteins makes it possible to stimulate or suppress specified types of neurons by literally shining light of different colours on them. This ability to manipulate different parts of a network or circuit is important because it establishes causal relationships between brain structure and function. Plan: Members of my lab will use optogenetics to manipulate the activity of different neural subtypes that create inhibitory signals in the cortex to discover their roles in shaping the information processing that generates perception and behavior. Our first long-term goal is to better explore perceptual abilities of mice by developing a battery of perceptual decision-making tasks so our optogenetic manipulations can be explored in a variety of contexts. Our second long-term goal is to use optogenetic control of the different inhibitory neuron subtypes to alter the function of local neural circuits or inter-areal networks and then link these changes to behavioral performance on perceptual decision-making tasks. Our third long-term goal is to link the optogenetic modulation of specific neural subtypes with changes in the stimulus selectivity of individual neurons in awake mice to bridge the gap between neural circuits and perception. Impact: The proposed work will provide tremendous training opportunities for Highly Qualified Personnel (HQP). It will also directly impact the visual neuroscience community by providing a more comprehensive understanding of how local circuits and inter-areal networks perform the neuronal computations that drive perceptual decision making. If local neural circuits are generally similar across the cortex, advances made in the relatively easy to study sensory areas may also provide insights into higher-order mental operations. Finally, improved models of neural information processing may refine biologically inspired algorithms for computer vision and artificial intelligence that have already found applications in self-driving cars, robotics, and manufacturing.