ABSTRACT The zebrafish has emerged as a useful model system to discover and characterize genetic and neuronal circuits that regulate vertebrate sleep. However, a limitation of this model is that sleep is determined using behavioral criteria and not the electroencephalogram (EEG) and electromyogram (EMG) measures that are used to define mammalian sleep and wake states.
ABSTRACT We propose to develop a targeted illumination confocal (TICO) microscope to enable high speed, large-scale voltage imaging in the brain. This microscope will be based on the combination of two key strategies. The first strategy is high-speed confocal microscopy based on line scanning. The benefit of confocal microscopy is that out-of-focus background is largely rejected by the use of slit detection. We will supplement this background rejection with the additional strategy of targeted illumination.
PROJECT SUMMARY/ABSTRACT Working memory, the ability to maintain and manipulate in formation in memory over a period of seconds, is a critical component of higher cognitive functions. Neurons in the prefrontal cortex and other brain areas continue to discharge during the maintenance of working memory however, little direct evidence exists on how neurons of different types organize into functional circuits to subserve these functions.
PROJECT SUMMARY/ABSTRACT In humans, damage to a brain region called the retrosplenial cortex leads to pronounced spatial disorientation and severe retrograde and anterograde memory deficits. Similar navigational and memory impairments are also seen in rodents with either lesions or chemogenetic inactivation of the retrosplenial cortex.
PROJECT SUMMARY/ABSTRACT Many animals rely on spatial cognition for daily survival in order to recognize familiar places and process movements through or between locations. A variety of space-encoding cells in the hippocampus are important for spatial behaviors in mammals. However, neural encoding of space remains uncharacterized in other vertebrate taxa, including amphibians, whose simpler brain structure suggests alternative mechanisms of encoding space.
How are complex behaviors that require the coordination of multiple muscle systems produced? How does the brain suddenly turn them “on”? Vocalizations are seemingly simple, yet to occur, ~100 muscles must be coordinated, such as those for articulation (laryngeal and tongue) and breathing. Moreover, vocalizations must seamlessly integrate with or perhaps even override the breathing rhythm. Innate vocalizations occur in multiple behavioral contexts, like mating, and are presumed to be initiated by a gatekeeper, the periaqueductal gray (PAG).
This proposal will investigate neural circuits driving negative phototaxis in an emerging model for neural circuit analysis: larvae of the primitive chordate Ciona. Ciona larvae have a number of features that make them ideally suited for this project. They are small and transparent, and have only 177 CNS neurons. Moreover, putative circuits for phototaxis have been identified from the Ciona connectome. Negative phototaxis in Ciona larvae consists of two phases.
Project Summary Primary motor cortex (M1) and the locus ceruleus (LC) both contribute in essential ways to the generation of purposive movements – with M1 and its pyramidal tract (PT) neurons involved in action planning and execution, the and LC and its noradrenergic axonal projections involved in aspects relating to arousal and attention. The cellular- and circuit-level mechanisms by which these two major brain systems communicate and interact are not well understood.
Project Summary: Memory enables animals to acquire, store, and recall knowledge of the world through experience and use this knowledge to maximize reward and avoid danger. Understanding the circuit mechanisms within and between brain regions that underlie the formation and recall of memories is considered one of the great scientific challenges of our time, and has the potential to drastically influence the treatment of memory disorders. The hippocampus is both necessary and sufficient for the formation and recall of episodic memories—memories of experiences placed in time and space.
PROJECT SUMMARY/ABSTRACT When learning in complex, realistic, or even real worlds, we have the benefit of using different strategies adaptively. For most primate brains, adaptive means adjusting as a function of where we are, who we are with, and what things of use are in view or in reach. Learning theories like Complementary Learning Systems (CLS) originally suggested that the hippocampus and neocortical structures contributed distinct computations to represent different kinds of memory.
