CAREER: Functional organization of auditory commissural networks

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Understanding how the brain processes sensory information remains one of the last great frontiers in science. Our entire worldview is constructed by our brains from the barrage of sights, sounds, feelings, tastes, and smells that bombard us on a daily basis. Even slightly perturbing one of these senses can drastically alter how we behave and interact with the world. Interestingly, neuroscientists are only now beginning to understand how particular brain circuits transform these sensory inputs into that which is experienced consciously. The research here is dedicated towards understanding the brain circuits responsible for processing auditory information. This research should ultimately have broader impacts to society, providing an increased understanding of how the brain operates in both normal and diseased states. Moreover, this work has even broader impacts, in that it furthers our understanding of the nature of brain, mind, and behavior, and ultimately the human condition. Finally, this research is integrated with an educational outreach effort, a science radio program, The Groks Science Show, which is syndicated and broadcasted nationally through the Public Radio Exchange (PRX), and distributed as a podcast and on internet radio stations, including NSF's Science 360 Radio. The primary objective of this research is to assess the role of the commissural projection systems in the auditory midbrain of the mouse. The central hypothesis is that excitatory and inhibitory cell types in this region receive convergent inputs from different sources, which differentially affect auditory receptive field formation. The research portion of this study will address two specific objectives: 1) Assessing the functional topography of inputs to excitatory and inhibitory neurons in the inferior colliculus and 2) Characterizing the neuroanatomical projections to excitatory and inhibitory cells in the inferior colliculus. These studies will employ laser-scanning phototimulation mapping of functional circuit inputs, as well as cell-type specific retrograde viral tract tracing, i.e. a modified rabies virus, SADΔG-GFP(EnvA) targeted using cre-lox recombination and AAV helper viruses. The proposed experiments should lead to further insight on the information-bearing roles of these auditory midbrain projections, as well as define the connectional architecture and functional properties of these connections in the mouse.