Neuronal plasticity and the evolvability of behavior

Washington University, Saint Louis MO

Investigators

Abstract

Behavior in all animals, including humans, requires four components in nervous systems to successfully interact: sensory organs that receive external stimuli, central pathways that process the sensory stimuli, pathways that coordinate and plan behavioral actions, and muscles that execute those actions. Our team will examine how these four components are sustained as behavior changes during development and evolutionary timescales. The central hypothesis of this project is that changes in behavior alter the sensory feedback an animal receives about that behavior, and this, in turn, modifies the brain in such a way that it drives coordinated changes between each of these four components. The researchers will test this hypothesis by capitalizing on unique experimental advantages of weakly electric fish to reveal fundamental mechanisms underlying evolutionary and developmental change in behavior. Electric fish are excellent tools for public outreach in neuroscience and behavior. As exotic animals, they attract a wide audience. The researchers will expand ongoing outreach and education activities to teach K-12 students in the St. Louis region about hypothesis-driven science and the importance of brain plasticity in behavior. The researchers will also establish a new pipeline to recruit students from Harris-Stowe State University, a Historically Black College and University, into biological research. The proposed research will play a central role in the training and development of undergraduate students, graduate students, and postdoctoral researchers. Nervous systems are complex, multifunctional, and highly integrated systems. Evolutionary and developmental change in behavior requires coordinated modifications to peripheral organs and multiple central circuits, which would seem to place strong phylogenetic and developmental constraints on nervous systems. Nevertheless, dramatic differences in behavior can arise between closely related species over relatively short evolutionary timespans. How can diverse behaviors evolve from constrained brains? The central hypothesis of this project is that activity-dependent wiring in response to altered sensory feedback drives coordinated changes between peripheral organs and central circuits. The researchers will test this hypothesis by capitalizing on the experimental advantages of mormyrid weakly electric fishes. These fishes are uniquely suited to addressing this challenging question, providing an unparalleled opportunity to gain fundamental insight into the role of activity-dependent plasticity in the evolution of behavioral novelty. The researchers will use a combination of hormone treatment and surgical manipulation to determine whether coordinated changes between peripheral organs and central circuits result from sensory feedback and plasticity. Electrophysiology and neuroanatomy will be used to identify the mechanisms underlying the resulting changes to central circuits, and to determine whether these same mechanisms are responsible for species differences in these circuits. The researchers will continue educational, training, and outreach efforts that are synergistic with the research and that impact K-12 students and educators, undergraduate and graduate students, and postdoctoral researchers. The researchers will also establish a new pipeline to recruit students from Harris-Stowe State University, a Historically Black College and University, into biological research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.