Systems Neuroscience

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.

PROJECT SUMMARY/ABSTRACT Higher brain functions include the ability to learn expectations about the world, update those expectations appropriately when given new sensory information, and use those continually updating expectations to guide behavior. How neural circuits implement these flexible information-processing dynamics is not known.

Project Summary (Overall: Cracking the Olfactory Code) Sensation drives perception, which informs decisions and actions. Olfaction is the main sense used by most animals to interact with the environment. However, olfaction remains shrouded in mystery — we do not know which molecular odorant features matter to the olfactory system and which do not, how information about these features is recombined to create holistic odor representations within the brain, or how those representations relate to perception.

Project Summary: Overall Local networks within the spinal cord represent an essential computational layer for the control of limb-driven motor behaviors, integrating descending and sensory inputs to coordinate dexterous motor output. Significant advances have been made in characterizing the developmental programs that specify the core cardinal interneuron types that make up these motor networks. This knowledge has been used to develop a battery of mouse genetic reagents for spinal circuit anatomical and functional dissection.

Project abstract Animals, including humans, interact with their environment via self-generated and continuous actions that enable them to explore and subsequently experience the positive and negative consequences of their actions. As a result of their interactions with the environment, animals alter their future behavior, typically in a manner that maximizes positive and minimizes negative outcomes.

Project Summary: The decision to commence a new behavior often requires termination of the ongoing behavior. This implies that the many drive states produced by an animal impact not only the neural circuits underlying their directly associated behaviors, but also those of many other behaviors. My lab has shown that the mating behaviors of male Drosophila are under motivational control and may be abandoned in the presence of stimuli evoking competing drives—depending on the relative intensities of the contending drives.

Project Summary/Abstract The overall goal of this project is to determine how output from the basal ganglia influences cerebral cortical activity in the processes of decision making, motor planning, and movement execution. The studies will employ mice as the best suited species in order to bring modern optogenetic and genetically encoded sensor technologies to bear on this critical gap in our understanding of brain function. In aim 1 we address the impact of basal ganglia output on network activity in cortex across sensory and motor areas.

Neural computation for innate behaviors in the superior colliculus The long-term goal of the proposed research is to understand how the brain makes sense of the onslaught of sensory data to extract just the few bits of relevant knowledge needed to make a decision. Specifically we will focus on innate behaviors of the laboratory mouse, such as the escape from a threat, the pursuit of small prey, and visual navigation.

Project Summary Behavior is movement, and the effective and efficient execution of movement has served as a fundamental evolutionary force shaping the form and function of the nervous system. Control of the forelimbs to interact with the world is one of the most essential achievements of the mammalian motor system, yet unfortunately these behaviors are particularly vulnerable to disease and injury. The execution of skilled limb movements requires the continuous refinement of motor output across dozens of muscles, suggesting the existence of feedback pathways that enable rapid adjustments.

SUMMARY To date, fundamental understanding of which features of odorants are decoded by the brain, and how information about these features is channeled through the olfactory system is still lacking. Odorants are sensed by the olfactory sensory neurons (OSNs) in the olfactory epithelium expressing specialized odorant receptors (ORs).