Circuit Diagrams

Project Summary Complex motor sequences are fundamental to many highly skilled behaviors, ranging from athletics to musical and vocal expression. Learning such complex movements requires both motor variability, to facilitate exploration important to reinforcement learning, and motor flexibility, to enable the adaptive modification of behavior in response to reinforcement signals. Studies of relatively simple skill learning, such as lever pressing or licking, emphasize that interactions between the motor cortex and the striatum are central to both exploration and reinforcement.

Project summary: Synaptic plasticity in brain structures like the hippocampus has been hypothesized to underlie an essential brain function - consolidating transient experiences into long-lasting memories. The importance of sleep for promoting long-term memory storage, and the disruptive effect of sleep deprivation on memory, have been appreciated for nearly a century. However, it remains unclear how sleep-associated changes in the activity of specific brain circuits contribute to synaptic plasticity in the hippocampus and other structures.

Project Summary/Abstract Sleep is necessary for all brain function and ultimately life. The core function by which sleep contributes to healthy cognition remains one of the great questions facing neuroscience. Recent theories point to powerful cellular rules, but these are controversial and have difficulty accounting for the effects of sleep in ethologically and developmentally diverse circumstances. We recently showed that cortical circuit dynamics are actively tuned to criticality, a computational regime that maximizes information processing.

Project Summary. Human and nonhuman primates are highly visual animals that are predominantly active during the daylight hours. Yet our understanding of the neural mechanisms supporting spatial navigation is largely based on studies of nocturnal, burrowing rodents with poor vision. Indeed, studies of human and nonhuman primates have already demonstrated that spatial positions can be encoded in the hippocampus exclusively by visual inspection of a scene (i.e. spatial-view cells).

Abstract To survive in dynamic environments, the nervous system must be able to generate flexible behavior — seamlessly weaving together past experience with the present context to achieve future goals. Our team of experts on the neural circuits of behavior will collaborate to reveal the neural mechanisms by which a mouse engages in specific processing of one sensory modality versus another based on task demands.

Learning desired actions from experience requires evaluating alternative actions by integrating the consequences assigned to each action over time. In the real world, actions and outcomes occur in complex sequences, and a continuous stream of events must be parsed into appropriate pairs of causative action and outcome before such pairs can be evaluated. However, how the brain solves this problem, known as temporal credit assignment (TCA) is unknown.

SUMMARY Adaptive behaviors emerge from neuronal networks by dynamically regulating functional connectomes. Based on an underlying anatomical connectome, a functional connectome is the configuration of effective synaptic connections that underlies a pattern of neuronal activity during a specific behavior. Unique combinations of neurons activate specific functional connectomes, thereby generating a behavior (a combinatoric code).

Summary, Overall (Thalamus in the middle: computations in multi-regional neural circuits) This collaborative project aims to uncover the logic of signal routing from subcortical areas to the frontal cortex through the thalamus. The frontal cortex displays rich patterns of neural activity, which can be decomposed into “activity modes” that correspond to specific aspects of behavior. Examples include the persistent activity correlated with short-term memory and motor planning, and the rapidly oscillating activity during voluntary movements.

Summary/Abstract, Core D: Behavioral Analysis and Modeling This proposal’s overarching goal is to understand how internal states influence decisions and to identify the underlying neural mechanisms. The Behavioral Analysis and Modeling Core’s development, testing, and application of statistical tools to rigorously characterize behavioral states is critical to achieving this goal.

Abstract We propose to investigate the role of neuromodulation in the phenomenon of “whole-cortex” activity of the pial neurovascular circuit. This circuit is composed of a network of pial arterioles that integrate neuronal activity with the intrinsic arteriolar vasomotion producing dynamic patterns of coherent oscillations in the arteriolar diameter effectively parcellating the cortical mantle. Prior research suggests that ascending neuromodulatory systems may work in parallel affecting the brain state and processing capacity of large-scale cortical networks.