Training

PROJECT SUMMARY Animals can exhibit goal-directed behaviors in novel environments, despite limited experience with them. How does the brain make and use inferences about the underlying statistics and generative structure of environments to guide behavior? The field of reinforcement learning refers to this capacity as “model-based” reasoning, meaning that it relies on an internal model of the structure of the world. Critically, this internal model can be used to flexibly estimate the best actions by mental simulation or planning, without direct experience.

TITLE: IDENTIFYING THE NEURAL MECHANISMS OF GOAL-DIRECTED DECISION-MAKING IN PARKINSON’S DISEASE USING CLOSED-LOOP DEEP BRAIN STIMULATION PROJECT SUMMARY People with Parkinson’s disease commonly suffer from non-motor symptoms, including motivation deficits, that impact quality of life more than classical

Project Summary Aggression is an evolutionarily conserved behavior that controls social hierarchies and protects valuable resources like mates, food, and territory. In most cases, aggression is a necessary, adaptive component of social behavior. In humans, however, some forms of aggression are considered pathological when they threaten lives, increase the risk of psychiatric impairment in victims, and incur economic burdens on society. Considerable evidence indicates that aggression is associated with aberrant facial perception in humans.

Project Summary/Abstract Mental disorders that affect the hippocampus disrupt people’s ability to form one-shot memories. My goal is to lead an independent lab, linking biological properties of hippocampal neurons to the ability to perform memory- guided cognitive behaviors. To map cognitive behaviors to their underlying neural mechanisms, my lab will perform theoretical analyses and simulation of state-space models of cognitive behaviors, implementing these models in a recurrent network architecture with learning rules that match biological plasticity rules (Aims 3a, c).

Motivational drive is an adaptive process that helps individuals overcome obstacles to obtain essential needs and hence ensure survival. Motivation is composed of two major components. The first component is the directionality of motivation (the orientation of goal-oriented behavior), such as seek food/shelter or avoid pain. The second is the activational motivation (the energizing of goal-oriented behaviors) such as increase vigor, and persistence of these actions.

Neuromodulation is crucial for information processing throughout the brain. Neuromodulators influence neuronal function by acting through G protein-coupled receptors (GPCRs) to alter neuronal excitability and synaptic transmission, which can then affect circuit functions. GPCRs are major drug targets used to treat a variety of diseases, including neurological disorders. The causal link between in vivo subcellular signaling mechanisms and behaviors is poorly understood due to the limited tools available to monitor signaling in freely behaving animals.

The initiation and maintenance of organized movement through the basal ganglia is strongly influenced by its feed-forward and feedback inhibitory architecture. The substantia nigra pars compacta (SNc) and pedunculopontine nucleus (PPN) contribute to the overall output of the basal ganglia. Neurons in both structures degenerate in Parkinson's Disease, resulting in impaired motion.

Food consumption is fundamental to species survival and understanding the neuronal circuitry underlying feeding behaviors is of the utmost importance. Amassing evidence supports the idea that control of caloric intake is complex and involves calculations of hedonic value, reward and motivation. Thus, it requires interactions between brain regions classically implemented in feeding (such as the lateral hypothalamus; LH) and the regions modulating reward (such as the ventral striatum).

The goal of this project is to provide the building blocks for an independent research program focused on the mechanisms by which neural networks incorporate multisensory cues into episodic memories. Discrimination of different contexts composed of distinct constellations of multisensory cues is a hallmark of both episodic memory and spatial navigation, two functions ascribed to the mammalian hippocampus.

Project Summary The ability to remember information, whether after short or long delays, is a fundamental human ability. There is enormous research into understanding working memory and long-term memory in isolation, but also a longstanding debate about the interactions between working memory and long-term memory.