UC San Diego

The primary challenge of systems neuroscience is identifying the circuits and cell types that underlie sensation and behavior. Faced with the daunting task of unraveling six layers of cortex, a hierarchy of visual areas, and a multitude of cell types, visual neuroscience relies on innovative technologies to achieve a circuit-level understanding of perceptual phenomena. This dissertation aims to be an extension of this effort by using advanced tools to address several longstanding questions regarding the structure and function of the visual system.

In the past decade, mouse visual cortex has come to the forefront of systems neuroscience, serving as a common ground to study the role of cell types in behavior. Armed with a remarkable arsenal of genetic and molecular tools in transgenic mice, we are poised to observe and manipulate visual circuits in a cell-type specific manner. Yet doing so requires a comprehensive understanding of the system at hand. In the work presented here, I extend our knowledge of the mouse visual system so that we may exploit its experimental advantages to address circuit-level questions.

Spanning multiple techniques and circuits, this dissertation investigates the mouse visual system from several angles. First, it refines our understanding of mouse visual cortex functional organization with bulk loaded calcium indicators and a well-studied higher-order stimulus, moving plaids (Chapter 1). Secondly, it characterizes the functional response properties of three different genetically defined layer 5 cell types, using in vivo two-photon imaging in the primary visual cortex (Chapter 2). Lastly, it delineates the topography of thalamocortical projections from the secondary visual thalamic nucleus (LP) to multiple visual cortical areas with classic tracing methods as well as novel viral combinations (Chapter 3). Together, these three studies advance our understanding of the connectivity and function of the mouse visual system, bringing us closer to bridging neurons and behavior.