Synaptic Organization and Function of Reticulospinal Sensorimotor Pathways

Cal Poly Humboldt Sponsored Programs Foundation, Arcata CA

Investigators

Abstract

This research seeks to determine how reticulospinal neurons mediate sensorimotor behavior. Sensorimotor behavior is any motor action that is guided by a sensory stimulus, for example, an itch guiding the hand to the correct spot to scratch. This requires three general steps in the nervous system. In the first step, the brain receives information about the stimulus through sensory nerves. In the last step, neurons in the brain send outputs to the spinal cord that specify muscle contractions. The middle step, which is the focus of this research, is the transformation of sensory signals into the appropriate motor signals. Hindbrain reticulospinal neurons receive sensory input and project axons to the spinal cord, but their function is not well understood. A detailed map of the synaptic inputs and outputs of reticulospinal neurons will be generated with the goal of answering two specific questions: 1. Do different reticulospinal neurons process information about different parts of the body?, and 2. Do specific reticulospinal neurons always connect to the same types of spinal neurons? Zebrafish larvae offer unique technical advantages for these studies, and since reticulospinal neurons have similar features across all vertebrates, what is learned in zebrafish may be applicable to other animals. The methods used will include neuroanatomy, neurophysiological recording, analysis of behavior, and computational modeling of neural circuits. Obtaining a detailed map of reticulospinal synaptic connections would not be feasible in other vertebrates, so this research has the potential to reveal new principles of reticulospinal sensorimotor function. This project will also have many positive impacts on education and student training at Humboldt State University. These include providing four students each semester with paid research assistantships, instituting a new course in cellular neuroscience, and making a confocal microscope system available to other faculty researchers.