Understanding Circuits

 DESCRIPTION (provided by applicant): Visual neuroscience is finally beginning to achieve a "vertically integrated" understanding of the retina, bridging all levels from molecules to microcircuits to behavior. Success could be achieved for all retinal microcircuits in just a decade, if progress were sped up drastically. Such acceleration will be attained by generating the following foundational data and disseminating it to the community.

 DESCRIPTION (provided by applicant): The cortex is a laminated structure that is thought to underlie sequential information processing. Sensory input enters layer 4 (L4) from which activity quickly spreads to superficial layers 2/3 (L2/3) and deep layers 5/6 (L5/6) and other cortical areas eventually leading to appropriate motor responses. Sensory responses themselves depend on ongoing, i.e.

 DESCRIPTION (provided by applicant): A key aspect of brain function is how the activity of neuronal populations encodes information that is used to guide behavior. A longstanding model system to understand population coding is the visual cerebral cortex, because its structure and anatomy are well understood, and because visual stimuli can be presented to subjects with high levels of temporal and spatial control.

 DESCRIPTION (provided by applicant): The function of a brain region is an emergent property of many cell types. The criteria needed to understand a network have been established in studies of invertebrate "simple" networks, but there has not yet been an attempt to provide such a full, mechanistic understanding of any network in the vertebrate brain. We believe that the time is now ripe for such an effort. Specifically, we propose to understand how the CA3 network in the hippocampus generates sharp-wave-ripples (SWR).

 DESCRIPTION (provided by applicant): Neuronal circuits in the brainstem control life-sustaining functions, in addition to driving and gating active sensation through taste, smell, and touch. We propose to exploit the advent of molecular and genetic tools to undertake cell lineage marking, cell phenotyping, molecular connectomics, and methods from machine learning and image processing to construct an integrated anatomical and functional atlas of the brainstem. This will enable us to generate anatomical wiring diagrams for the brainstem circuits that control or facial actions.

 DESCRIPTION (provided by applicant): Behaviors are sequences of actions that are executed in the proper order and correct setting to achieve a goal. Action sequences and their association with the specific environmental contexts in which they are beneficial can be hardwired, as in the case of innate behaviors, or learned and flexible, as in the case of adaptive responses to changing surroundings.

 DESCRIPTION (provided by applicant): The brain evolved complex recurrent networks to enable flexible behavior in a dynamic and uncertain world, but its computational strategies and underlying mechanisms remain poorly understood. We propose to uncover the network basis of neural computations in foraging, an ethologically relevant behavioral task that involves sensory integration, spatial navigation, memory, and complex decision-making.

 DESCRIPTION (provided by applicant): The brain is a massively interconnected network of regions, each of which contains neural circuits that process information related to combinations of sensory, motor and internal variables. Adaptive behavior requires that these regions communicate: sensory and internal information must be evaluated and used to make a decision, which must then be transformed into a motor output.

 DESCRIPTION (provided by applicant): The purpose of this RFA is to promote the integration of experimental, analytic and theoretical capabilities for the examination of neural circuits and systems. This proposal is highly responsive to the RFA in that it links several different neuroscience labs to develop new technologies that provide for simultaneous multistate imaging and applies these technologies to the examination of how neuronal dynamics in mammalian cortex varies as a function of brain state and development.

 DESCRIPTION (provided by applicant): The system that controls smooth pursuit eye movements is one of the most accessible, promising systems for understanding how neural circuits transform sensory inputs into actions. Pursuit is a natural, ecologically- relevant behavir that allows primates to track moving objects of interest in the visual world.