Alan J. Emanuel, Ph.D. - US grants

The ability of our nervous system to represent the sensory environment requires a hierarchy of processing from the peripheral sensory receptors to sensory association areas in the cortex. While the overall structure of this hierarchy of the somatosensory system has been well-described, how information is represented at each level is not as well understood. Therefore, the goal of this proposal is to reveal how information from the peripheral somatosensory system is integrated into the representation at the primary somatosensory cortex. We will use two-photon calcium imaging and in vivo electrophysiology with carefully applied mechanical stimulation to elucidate the spatial organization of mouse somatosensory cortical neurons with defined tuning properties. In particular, we will focus on how information is represented with single-cell resolution within cortical layers and how information is represented and transformed at different levels of the cortical hierarchy. Selective activation and silencing of peripheral mechanoreceptors will be used to determine the sufficiency and necessity of subtypes of mechanoreceptors for the production of tuning properties within neurons of primary somatosensory cortex. These experiments will enhance our conceptual understanding of information processing in sensory cortices, potentially leading to enhanced design of brain-machine interfaces.

Career Plan and Environment of Career Development: Dr. Emanuel is a joint postdoctoral fellow in the laboratories of Drs. David Ginty and Chris Harvey who is dedicated to a career as an academic researcher. Drs. Emanuel, Ginty, and Harvey have developed a 12-point career development plan that will enable Dr. Emanuel's transition to an independent research position. This plan incorporates resources available at Harvard Medical School, including formal and informal training from the community within the Department of Neurobiology and the broader Harvard Medical School community. Formal training includes attendance at seminars on professional development and responsible conduct of research as well as engaging the wider scientific community with publication of manuscripts describing Dr. Emanuel's work and presentations at international meetings. Overall, this plan will optimally prepare Dr. Emanuel for the transition to an independent career. Research Plan: The goal of this project is to determine how the representation of complex features in primary somatosensory cortex are produced by cortical and subcortical neural circuitry and how these representations are adapted for the behavior of the animal. Specifically, the experiments in this proposal will use mouse genetic approaches and in vivo electrophysiology to address the neural underpinnings of speed, direction, and orientation tuning in primary somatosensory cortex (Aim 1). Combining in vivo electrophysiology with genetic manipulations and recording from primary somatosensory cortex will determine the extent to which these cortical representations are necessary for and adapt to performance of tactile behaviors (Aim 2). Finally, combining in vivo electrophysiology in freely moving animals with modern computer vision for monitoring behavior and the force applied to the skin will determine how neurons in primary somatosensory cortex are engaged during natural movements and environmental interactions (Aim 3). In all, these experiments will yield insight into the fundamental processes underlying sensory processing in the central nervous system.