Jonathan F. Prather, Ph.D. - US grants

[unreadable] DESCRIPTION (provided by applicant): This study of song perception by songbirds will contribute to the long-term goal of understanding neural mechanisms underlying human perception of speech. The focus of these experiments is the role of auditory neurons (HVc nucleus) in categorical perception (CP), wherein continuous differences in song stimuli are perceived as instances of discrete categories. Previous behavioral tests have revealed features of birdsong that evoke CP in swamp sparrows, and those features will be duplicated in this study. In the first experiment, intracellular recordings of HVc neurons will reveal whether individual neurons express categorical responses to song stimuli. If categorical responses are evident, comparison of subthreshold and action potential responses will reveal whether categorical boundaries are established in HVc or in sites presynaptic to HVc. In a second experiment, extracellular recordings of HVc neurons in awake and freely behaving birds will reveal whether categorical behavioral responses to song stimuli are accompanied by categorical responses of HVc neurons. These data will provide new insight into the role of HVc neurons in the perception of auditory signals and may suggest mechanistic features of human perception of speech. [unreadable] [unreadable]

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Communication through speech is an invaluable part of human health, dramatically facilitating self-expression and enriching personal relationships. Fundamental to this process is the planning and sequential performance of vocal sounds. Motor disorders such as apraxia of speech and stuttering can dramatically disrupt vocal sequencing, severely impairing communication and often evoking harsh ridicule and social isolation. In each disorder, symptoms are thought to arise from anomalies in regions of the central nervous system involved in sequencing the performance of individual sounds, but effective therapies will require detailed knowledge of the deficits that accompany each condition. Presently, the neural circuitry and synaptic mechanisms that shape sequencing of human speech remain largely unknown. Neuroimaging studies suggest important roles for premotor and speech-related cortical areas and the basal ganglia in vocal sequencing. However, neuroimaging techniques do not provide sufficient spatial or temporal resolution to describe the underlying events in neuronal circuits, necessitating use of an animal model of human speech. Songbirds provide an established model of human speech. Both speech and birdsong are learned vocalizations characterized by careful regulation of tonality and vocal sequence, and the songbird brain contains a set of discrete structures specialized for song performance and perception. One structure, nucleus HVC, is essential for song production and important in song perception, indicating functionality analogous to human speech-related cortical areas. HVC directs vocal output through separate projections into premotor (HVCRA) and basal ganglia (HVCX) pathways, and HVC activity directs the timing of individual song features. Furthermore, HVC receives synaptic input from brain regions proposed to regulate vocal sequencing, suggesting that HVC may encode not only timing but also sequencing of vocal production. The song of one species, Bengalese finches (BF), contains individual vocal sounds produced with variable sequence in some portions and fixed sequence elsewhere, providing an animal model of variable and fixed sequencing in human speech. Preliminary studies indicate that activity in at least one input to HVC can modify BF song sequence. Thus, studies of HVC and its afferents in BF will enable synaptic-level analysis of how fixed and variable vocal sequences are encoded in premotor and basal ganglia pathways. The proposed project will investigate the activity of identified neurons in HVC and its synaptic afferents during BF performance of natural and artificially manipulated vocal sequences. AIM 1 will alter activity of afferents to HVC to establish which sites are sufficient to induce changes in vocal sequence. AIM 2 will characterize the singing-related activity of individual neurons in those afferent sites, revealing how naturally fixed and variable vocal sequences are encoded by those structures. AIM 3 will characterize the activity of HVCRA and HVCX neurons as birds sing with or without the afferent manipulations used in Aim 1, revealing how acquired alterations of vocal sequencing are encoded in premotor and basal ganglia networks.

Decisions define the course of a person's life, profoundly impacting health, safety and economic prosperity. The process of decision making involves two key components: assessing the value of a sensory stimulus or anticipated outcome, and taking action based on that evaluation. In humans and other mammals, neural networks involving the association cortex and reward centers have been implicated in stimulus evaluation, while other networks have been implicated in motor planning and initiation. What remains unknown is the circuit through which evaluation directs selective motor activation. Defining this link is essential to understand decision making, and this project will investigate natural social behaviors in a new animal model of decision making to reveal how the nervous system forges that link between perception and action. An improved understanding of decision making and social behavior will advance many fields including neuroscience, psychology, and economics. Furthermore, this research will also guide understanding of how decision making can go awry, yielding the promise of mechanistically-targeted treatments for behavioral pathologies such as compulsive behavior and addictive relapse. Such advances will vastly improve not only quality of life but also national economic competitiveness. This broadly relevant and appealing research will be integrated with the educational goal of engaging high-school students and teachers in laboratory research, developing the next generation of professional scientists, and communicating these and other findings to the public through an educational series of relaxed and informal Science Cafes.

In female songbirds studied in this project, songs that they hear performed by males are the most important factor influencing the female's mate choice. A female's preference for a specific song and the behavioral indicators of that preference are easily quantifiable and consistent over time, providing a context in which to investigate how the brain encodes preference and uses that information to direct selective expression of behavioral responses. In these experiments, the researchers will (Aim 1) identify how subjective value of male song is encoded in specific populations of neurons in the female brain. Additional experiments will (Aim 2) identify circuits through which sensory processing of subjective value directs motor behavior. In those experiments, focally applied, low-intensity light will be used to activate or inactivate those circuits to discern the causal relation between activity in those pathways and performance of specific behavioral responses. Together, these experiments will reveal the link between perception and action.

This project aims to serve the national interest in excellent undergraduate education by helping students better understand processes involving biological molecules. Biology textbooks and teaching materials use two-dimensional static images to show complex three-dimensional molecules and molecular events that occur over time. As a result, students often need help to understand these processes, such as protein folding, protein-protein interactions, and DNA replication, and RNA transcription. These processes occur on a scale that is starkly different from everyday human experience, making understanding them even more challenging. This project intends to use networked augmented reality (AR) technology to make molecules and their interactions visible to students on a human scale. AR technology will also allow multiple users to control 3D representations of molecules, enabing students work together as a group to learn about molecules and their interactions. The project intends to examine how the AR experience alters students? understanding of molecules and processes at the molecular level, as well as test whether student learning is improved by social interactions in a networked augmented reality environment. Once the materials and software developed by the project are ready for classroom use, they will be made freely available via Creative Commons licensing.

The goal of this project is to advance STEM education by developing intuitive ways for students to engage with molecular-scale phenomena. To do so, the project will harness AR as a tool to bring molecular phenomena to life and to present them in a social context that promotes active engagement and long-term learning. Networked AR headsets will allow multiple users to view and control a shared 3D simulation from multiple points of view, and pass-through visualization will create a safe and naturally socially mediated AR environment. Each student in a group will have a unique role and individualized access to relevant information, ensuring a collaborative student-led effort to develop their conceptual and quantitative understanding of molecular phenomena as they explore a series of lessons and challenges. The 3D simulations will react in real time to student control of relevant parameters and will include continuously updating graphs and other mathematical representations. The research goal of this project is to investigate best practices for incorporating head-mounted AR technology in STEM education by testing the effects of two teaching strategies: student engagement in collaborative social interactions and engagement with 3D instruction environments. Project success will be measured by quantitative assessment of four learning outcomes: accuracy of factual understanding; use of expert language; fluency of quantitative reasoning; and tendency to communicate complex spatial relationships using 3D examples or analogies. The long-term goal of the research is to create freely available socially mediated AR instructional resources that deepen students? understanding of molecular-scale phenomena and quantitative relationships that are integral to STEM courses across all grade levels. Through networked interactions within these interactive environments, socially mediated AR has the potential to increase equitable access to STEM learning, by providing educational opportunities for students across rural regions and in other situations that creaet accessibility challenges. The NSF IUSE: EHR Program supports research and development projects to improve the effectiveness of STEM education for all students. Through the Engaged Student Learning track, the program supports the creation, exploration, and implementation of promising practices and tools.

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.