Research Projects

PROJECT SUMMARY In order to forage effectively for food, the brain must integrate innate and learned information about the value of different food odors and use this information to select navigational motor programs. Although a great deal is known about how the brain computes the value of odor stimuli, how it uses this information to guide navigation remains mysterious. Here we propose to investigate the role of a conserved navigation center, the fan-shaped body (FB), in olfactory navigation.

Abstract Our brains have evolved to extract relevant sensory information from rich and complex natural environments in order to drive appropriate behavior. Multiple brain structures can play a role in such processing, and while cortex is often most prominent in mammalian studies, many behaviors can also be mediated by superior colliculus, particular orienting and avoidance responses to salient stimuli.

Motor neurons connect to muscles and comprise the major output of the nervous system. Patterns of neural activity in motor neurons cause temporally precise muscle contractions, producing coordinated and flexible behavior. These patterns are shaped by the connectivity and physiology of premotor circuits in the spinal cord that synapse onto the motor neurons. Premotor circuits combine descending motor commands with sensory feedback signals to drive motor neuron activity.

Summary Animals actively sample sensory information, which they combine with prior knowledge to make decisions in a sensorimotor feedback loop. Aspects of this complex loop are often studied in isolation, using trial structures and in simplified conditions such as head-restrained animals in virtual reality.

PROJECT SUMMARY How our brain achieves coherent perception by integrating information from parallel sensory pathways distributed across space and time remains a central question in neuroscience. In the auditory system, sound information reaches the cortex via the lemniscal (“primary”) and non-lemniscal (“secondary”) pathways. The non-lemniscal pathways have often been described as slower integrators of multi-sensory information, in contrast to the roles of the lemniscal pathways as fast and reliable relays for sound inputs.

Abstract The transformation of visual cues into appropriate behavior requires the collaboration of diverse neurons across distant brain areas. A fundamental gap in our knowledge about these visuomotor transformations is understanding how these neurons are functionally connected, shaping neural response dynamics that give rise to behavioral output. This gap is due to the inaccessibility of mammalian model systems, in which simultaneous in vivo observation and manipulations across the brain is impossible as well as a lack of real-time computational frameworks that can capture these dynamics.

Feedback and feedforward gating of sensory signaling through timing in the thalamocortical loop Nearly all sensory experience begins in the periphery, generating sensory signals travelling through the thalamus before reaching neocortex. Despite numerous anatomical and functional investigations into the feedforward projections from thalamus to primary sensory cortex (TC), significantly less is known about the extensive reciprocal corticothalamic (CT) feedback pathway that provides ~40% of input to the thalamus.

Project Summary Neuroscience is entering a new era, where large-scale neural network models can be tested with unprecedent- edly rich measurements of neural activity. This proposal develops a general methodology for linking theory to experiment in this new era and applies the methodology to the problem of primate face recognition.

Project Summary The cerebellum is essential for coordinating motor behavior through rapid adjustments of ongoing movements. To refine movement, the cerebellum processes motor and sensory information, and transmits output that ultimately modulates motor neuron activity to ensure successful execution. The path through which the cerebellum can influence limb movement is through output circuits in the cerebellar nuclei (CN). Yet little is known about how CN circuits are organized and whether discrete pathways are dedicated to specific motor functions for limb control.

Project Summary Animals interact with the world through dynamic, iterative sensory-motor processes that guide their ongoing movement. Odor-guided navigation is the basis for fundamental natural behaviors such as finding food sources, but little is known about the nature of the sensory signals that inform adaptive changes in locomotion. Here we propose to test how spatial information is encoded by distributed activity in the olfactory bulb, and how this information is decoded by higher-order brain areas.