Contextual modulation in the mammalian primary visual cortex: linking neural circuits to perception

It is widely appreciated that the brain has a remarkable capacity to process incoming information. The overall goal of my research is to understand the processes happening in the brain that allow us to see the world around us. Although the eyes detect light, most of what is commonly thought of as vision actually arises from analyses performed by a chain of interconnected brain regions called the geniculo-striate pathway. Research in my laboratory focuses on the first cortical stage of this pathway called the primary visual cortex (V1) where individual brain cells (or neurons) have the ability to detect basic features in a visual scene such as lines of a specific orientation at a particular location in space. The selectivity of an individual V1 neuron can change based on what has been seen previously, the spatial layout of the scene, or even what the animal is doing at the time. Studying this 'contextual modulation' will give a more complete understanding of how V1 works because vision in everyday life has a temporal, spatial, and behavioral context. It has long been conjectured that both the basic properties of V1 neurons and contextual modulation arise through specific connections between different types of neurons called neural circuits. Efforts to link neural circuits with perception have been aided by recently developed tools in the field of optogenetics that make it possible to stimulate or suppress specified types of neurons in a circuit by shining light on them. Optogenetic tools are mainly applied in mice, and I have extensive experience working with this species. In my novel and exciting research program, members of my lab will use optogenetics in mice to study several aspects of contextual modulation for the first time. Our first objective is to study how inactivating V1 or brain areas that connect with it affects context coding. Our second objective is to isolate the roles of specified types of V1 neurons in contextual modulation. Our third objective is to establish techniques to study visual perception in awake mice to bridge the gap between neural circuits and perception. The proposed work will benefit the visual neuroscience community by providing a more comprehensive understanding of how the properties of V1 neurons arise from specific cell types arranged in neural circuits. This will help improve existing models of how the brain codes visual information, and may provide insights into how information is represented more generally across the nervous system. A better understanding of how the brain encodes visual information could also inspire biomimetic algorithms for computer vision and artificial intelligence. Although it is a distant goal at present, the development of a seeing machine with the ability to use visual information to interact with its surroundings just as well as humans (or even mice) would have far reaching applications ranging from security, to manufacturing, to space exploration.