Understanding Circuits

Project Summary/Abstract The Research Plan describes a series of experiments that will examine how spatial information is processed in the mammalian brain. Previous studies have identified a population of cells that are tuned to a subject’s directional heading These so-called head direction cells are thought to underlie one’s sense of direction. The neural basis for this computation is believed to reside in an attractor network at subcortical levels.

Project Summary Animal brains integrate information to make crucial developmental and behavioral decisions. The brain adapts to life experiences by anatomical, functional, and molecular changes, but understanding the strategic value of these changes requires a comprehensive model that interconnects neural circuits and behavioral dynamics. To develop such models, it is useful to start with animals where entire brain circuits can be interrogated with full molecular, synaptic, and cellular resolution across development.

PROJECT SUMMARY Cortical circuits generate dynamic patterns of activity. One of the great challenges of modern neuroscience is to determine the circuit architectures that generate such dynamics patterns, and understand their genesis and functional significance. Most research on brain dynamics focused on stable patterns of activity showing continuous transitions (e.g., oscillations). However, in recent years there has been an increased interest on transient dynamics, including the ones resulting from the sequential switching between metastable states.

Project Summary The goal of this proposal is to identify fundamental sensorimotor circuits associated with goal-oriented gripping movement by using high-dimensional biological, analytical and robotics technologies. To pursue this, we will study an animal that is extraordinary in many ways, the octopus. Our interest in this unique invertebrate is based on its well documented complex behavior repertoire that have shown to resemble those of vertebrates. Each of the eight arms contains an axial nerve which functions like the vertebrate’s spinal cord.

Project Summary Mechanistically linking network connectivity and the dynamics of neural networks to variation in the behavior of individuals is an overarching goal of neuroscience. Here we address this goal using techniques from network science to calculate functional networks that summarize pair-wise and higher order interactions between all recorded neurons.

Project Summary Navigating within an odor plume is a complex task due to unpredictable changes in odor concentration. The algorithms used by organisms to navigate the odor plume remain mysterious and how the brain solves this complex sensorimotor task key to escaping, mating and eating is unknown (1). The problem is challenging because it requires parallel monitoring of: 1) brain activity in multiple brain regions in the freely moving animal, 2) odor plume dynamics, 3) sniffing and 4) animal motion.

PROJECT SUMMARY / ABSTRACT Our current understanding of primate motion perception is often lauded as one of the great achievements of computational systems neuroscience. Due to its early successes in explicating the fundamentals of neural coding and relations between brain activity and perception, and further constrained by the practical limitations of the macaque model, it has remained rooted in conventional experimental approaches.

Project Summary / Abstract How do cortical populations represent sensory input and support perceptual decision making? It has long been known that the responses of individual neurons to the repeated presentation of a stimulus are highly variable. Nonetheless, the pattern of activity across a population encodes enough information to support precise perceptual decisions. This implies that hidden in the distribution of population responses there are invariant features, yet to be identified, which robustly encode the sensory stimulus from one trial to the next.

PROJECT SUMMARY Pattern separation is the process by which the brain distinguishes between similar or overlapping features of the external world. This fundamental computation is performed by multilayered circuits – including the dentate gyrus, cerebellar cortex, and insect mushroom body – that expand and diversify neural representations. Diversity in “space” (i.e.

Project Summary/Abstract Maintenance of body temperature at the optimal level is crucial for survival, and it requires homeostatic feedback regulation based on monitoring the temperature of internal organs as well as the environment. Homeostatic thermoregulation in response to changes of brain temperature relies on the temperature- sensitive neurons in the preoptic area of the anterior hypothalamus (POA).