Understanding how the brain controls behavior is a major goal in neuroscience. All behavioral actions, including those as different as walking, singing, even tiny eye movements that allow one to focus on a page of text, ultimately depend on the activation of muscles by motor neurons in the brain. The remarkable range of actions that animals are capable of begs the question: how different are the motor neurons underlying different behaviors? One strategy for answering this is to compare neurons driving different behaviors. Modern bony fishes are champions in the ability to generate vocalizations that exhibit rapid, precisely timed sound pulses. The studies proposed here use fish as model systems to compare vocal motor neuron populations to those that pattern non-vocal motor behaviors: locomotion that depends on fin movement, and electric signaling generated by modified muscle cells that are used by fish for communication and active sensing of the aquatic environment. The project will determine the extent to which molecular, genetic and physiological properties are shared in motor neurons driving these behaviors that differ in their temporal patterning, for example, fast (vocal and electric) vs. slow (fin movement). The Principal Investigator will continue to recruit a talented population of men and women students from diverse backgrounds, including underrepresented minorities, and train them in behavioral, neural, and molecular levels of analysis.
More specifically, molecular, genetic and neurophysiological methods in several model systems among fishes will be used to address the following questions: 1) Can similarities in the neurophysiological patterning of vocal motor behavior between distantly related species be explained by a similar set of gene products that underlies a shared set of vocal motor neuron characters (Aim 1)? 2) Do vocal motor neurons employ a "molecular toolkit" distinct from that of non-vocal motor neurons exhibiting lower degrees of synchrony and temporal precision, in this case the pectoral motor system for locomotion (Aim 2)? 3) Do vocal motor neurons employ a shared "molecular toolkit" with that of non-vocal motor neurons exhibiting comparable degrees of synchronicity, temporal precision and rapid firing, in this case the electromotor system that is used for active sensing of objects in the aquatic environment (Aim 3)? By complementing large-scale gene expression studies with neuro-pharmacological validation, these aims will identify how patterns of gene expression determine neurobiological and behavioral phenotypes, in this case those determining divergent motor functions.
