MCA Pilot PUI: Neural Signaling and Mechanisms Underlying Sensory Integration and Plasticity

Western Washington University, Bellingham WA

Investigators

Abstract

Researchers have long investigated how signals are received and processed by individual neurons and within neural circuits. However, little is known with regards to how neural circuits reconcile competing signals that drive opposing behavioral responses; therefore, investigating how neural circuits integrate and/or reconcile opposing response circuits could lead to the discovery of new and exciting learning processes. To observe how neural circuits accomplish this signal integration, this project utilizes a learning assay in a nematode, previously described by the primary investigator. For this learning protocol, two stimuli that each drive an innate, opposing locomotor response (i.e., forward vs backward locomotion) are paired. This pairing does not augment the later response to a single stimulus, but rather results in a novel response outcome, a cessation of locomotion; thus, the innate responses activated by these stimuli qualitatively impact the conditioned response. This learned response stabilizes over minutes and may involve modulation from neurons that are downstream from the interneurons where signal integration likely occurs (e.g., motor neurons). This award supports collaborations between the primary investigator and two faculty partners to pursue multiple avenues of investigation. Through these collaborations, the primary investigator will gain access and expand her skill set to include state of the art genetic tools as well as advanced microscopy techniques that will allow for observing activation of single neurons either during stimulus pairing in behaving animals or following stimulus pairing in immobilized animals, targeted activation of single synapses or subset of synapses predicted to be involved, and behavioral analysis of mutant strains to investigate the possible role of the neuron-supporting glial cells in forming the learned response. This project will provide meaningful research opportunities to a number of undergraduates in the primary investigator’s laboratory and in a course-based undergraduate experience (CURE) lab course. By establishing these techniques at the primary investigator’s home institution, this project will expand the available tools for scientific enterprise. This project combines modern genetic tools and imaging approaches to visualize the dynamics in neuron activity and uncover cellular mechanisms involved in neural circuit signal integration and learning in C. elegans. To identify neurons activated during and after pairing of opposing locomotor response neural circuits, fluorescence from the NeuroPAL unique neuron marker will be captured simultaneously with GcAMP (a genetically-encoded calcium indicator) fluorescence. Strains of C. elegans that express light-sensitive ion channels genetically targeted to specific neurons will be employed to activate/deactivate targeted circuits during paired signal presentation. To target a single synapse or set of synapses involved in circuit integration, this project will combine optogenetics with patterned point illumination and super resolution/FLIM confocal microscopy. Finally, using targeted mutations the potential role of glial cells in facilitating learning following this stimulus pairing will be explored. This project has the potential to reveal a new understanding for how individual neurons, circuits, and/or glia participate in integrating simultaneous opposing response signals and how this experience alters an organisms’ behavior. This award affords the principal investigator supported time to learn these genetic and microscopy approaches and incorporate these skills into her laboratory’s research program and lab courses, providing undergraduates with a meaningful research experience and the opportunity to work with a female primary investigator who is an underrepresented minority in science. Faculty at the primary investigator’s home institution will benefit from the expanded local tools available from the introduction of these modern techniques. These approaches will also be disseminated to other Neuroscience faculty at undergraduate institutions through a workshop at the next Faculty for Undergraduate Neuroscience Conference. 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.