Research Projects

Project Summary All animals share motivated behaviors to fulfill their basic needs for survival, including food, water, sleep, and social interactions, etc. The homeostatic regulatory system energizes behaviors to defend a target level for these needs (the homeostatic setpoint). For example, human adults, on average, aim to sleep 7-8 hours daily. What defines the homeostatic setpoint and how is it modulated remain unanswered questions for all motivated behaviors. Do dedicated neural circuits exist that determine the setpoint?

PROJECT SUMMARY Social insects show robust and complex behaviors, and have served as important study systems in ethology for decades. However, because they are not genetically tractable, researchers have not been able to study these behaviors at the level of brain circuitry with cutting-edge neurogenetic tools. The proposed work will pioneer such tools in the clonal raider ant Ooceraea biroi, a species that uniquely combines experimental amenability with the fascinating behavior of social insects.

ABSTRACT Short-term memory is an essential component of cognition. Here, we will investigate an ethologically relevant form of short-term memory that guides navigation behavior: memory of odor concentration across sniffs. This intersniff memory has been shown to guide olfactory search in studies of freely moving animals, but the stimuli in these experiments are hard to control and measure. To better control concentration fluctuation, we have developed a system for presenting stimuli that rapidly change concentration to head- fixed mice.

PROJECT SUMMARY The precise assembly of neural circuits ensures accurate neurological function and behavior. For example, to communicate specific aspects of the visual world to the brain, retinal ganglion cells (RGCs) find and form synaptic contacts with specific postsynaptic partners out of the heterogeneous neuronal population of retino-recipient areas in the brain. One such area is the superior colliculus (SC), which receives direct retinal inputs and sends commands for direct innate behaviors such as escape or prey capture.

Project Summary/Abstract This proposal responds to an FOA (RFA-NS-18-030) calling for 1) “novel approaches to understand neural circuitry associated with well-defined social behaviors;” 2) Distributed circuits that contribute to the coordination of motivational states and reward behavior;” 3) “Empirical and analytical approaches to understand how behavioral states are emergent properties of the interaction of neurons, circuits and networks.” The study of subcortical circuits that control conserved, naturalistic behaviors is crucial to understanding brain function.

Project Summary Internal sodium balance is critical for many physiological functions, including osmoregulation and action potentials. Deciphering the mechanisms that control sodium intake is essential for understanding the principles of appetite regulation and sodium homeostasis in the body. Our understanding of central sodium appetite regulation is still lacking compared to other appetite circuits such as thirst and hunger. I propose to study this fundamental brain circuit that controls our internal ion balance using transcriptomic and molecular genetic tools.

Genetic and neural mechanisms underlying emerging social behavior in zebrafish Our goal is to understand emerging collective behaviors of groups, such as schooling and shoaling in fish. Our approach is to dissect basic sensorimotor transformations in the zebrafish, which we believe play a fundamental role in explaining emerging social interactions.

Abstract Recent technological advances have led to the realization recording devices that can sample neuronal activity from up to a few hundred channels in a limited area. These innovations reveal the importance of understanding circuit computations – and highlight the current inability to record individual neuron spiking activity across multiple scales, particularly without creating a prohibitive cost barrier.

Neuropeptides are important signaling molecules that regulate brain states, modify neural activity and control vascular tone in the nervous system. Pharmacological and molecular genetic studies have implicated changes in neuropeptide signaling with brain dysfunctions, such as alcohol abuse, drug addiction, and stress. Released via dense-core vesicles into the extrasynaptic space, neuropeptides diffuse over long distances (i.e., volume transmission), and activate G protein coupled neuropeptide receptors.

PROJECT SUMMARY / ABSTRACT To understand the highly integrated cognitive processes in the mammalian brain, and the neuronal basis of com- plex and ethologically relevant behavior, one requires fast, depth-penetrating and volumetric imaging techniques that are compatible with free behavior such as during social interaction. To date, however, no method exists that allows Ca2+ imaging during free behavior and can be scaled up to large and curved brain surfaces while at the same time is capable of extracting neuronal signals at physiologically relevant time-scales (e.g.