Cellular mechanisms underlying the development of visually-guided behavior

Brown University, Providence RI

Investigators

Abstract

The only way to truly understand how the human brain works is to understand how it is first put together during early development. To do this, we need to first grasp, at a basic level, the fundamental principles by which developing brain circuits are initially formed and how early experience can shape these connections. This project addresses these questions by studying the development of the visual system of tadpoles from the African clawed frog, Xenopus laevis. This relatively simple brain circuit allows investigators to ask highly tractable questions about early brain development and answer them by designing experiments that investigate development at the level of single brain cells to the more complex behavior of brain circuits, and ultimately, to complex behaviors. Thus, these studies will provide an understanding of the mechanisms underlying visually guided behavior from initial perception in the eye all the way to behavioral output. An in-depth, integrated, view of this developing brain circuit can be used to derive fundamental principles of brain development. Remarkably, these principles have been shown to be applicable to all vertebrates including humans. This proposal continues a program established by the investigator to run a Neuroscience Summer Fellowship at Brown University for underrepresented minority high-school students, with the goal of increasing the participation of these students in careers related to Science, Technology, Engineering, and Mathematics (STEM). Specifically, this proposal seeks to understand the mechanisms by which neural circuits in the Xenopus tadpole optic tectum allow the organism to process incoming sensory information and transform it into meaningful motor output. This sensory-motor transformation is essential for the organism to interact with its environment. Data from many levels of analysis will be integrated, including recording from retinal ganglion cells in the eye, recording the balance of excitation and inhibition and spike output of the tectum in vivo, recording network activity of multiple tectal cells in vivo using calcium imaging, quantifying visually guided behavior with a high speed camera, and using dynamic clamp to probe the integrative properties of tectal neurons in response to behaviorally relevant stimuli. Together these data will give us an unprecedented understanding of the steps and circuitry involved.