Neural Circuits Underlying Volitional Movement
Movement is central to our “selves”. Our behavior is defined by movements. The way we move projects our image and has deep social psychological consequences. My lab seeks to understand the neural underpinning of how movements are generated. We focus on volitional movements, the movements that are directed at a goal (e.g. a quarterback making a throw). Volitional movements are not reflexes. The brain preprograms, or plans, volitional movements before they are executed. In the cerebral cortex of humans and primates, persistent neural activity anticipating a movement can emerge seconds before the movement occurs. This persistent activity is thought to be the substrate of planning that give rise to the future movement. Persistent activity is observed in multiple connected brain regions, suggesting that the underlying neural circuits are a distributed set of structures that are selectively coupled. Our research is aimed at understanding how distributed circuits in the mouse brain orchestrate persistent activity and produce movements.
To get at these mechanistic questions, we use a variety of approaches to delineate when and how activities in specific brain regions contribute to the planning and execution of volitional movement. First, we combine high throughput behavioral testing with comprehensive loss-of-function screen to identify the structures casually involved in motor planning. We then use multi-electrode recording, 2-photon imaging, and optogenetic perturbations to relate the activity dynamics in these regions to specific aspects of motor planning behavior. To understand how the underlying neural circuits give rise to these dynamics, we combine recordings and manipulations of anatomically defined neurons to perform circuit analysis, with a focus on circuit nodes that connect the involved brain regions. Many of our approaches require us to develop new techniques to access and manipulate specific neural circuit nodes in intact animals during behavior.
Damages or neurodegeneration of the motor planning neural circuits affect a wide range of daily functions such as gestures, skilled movements, and speech. Electrical activity of neurons and cellular properties form the basis of neural circuits. Our goal is to establish platforms upon which we can understand why and how cellular or genetic dysfunctions are linked to abnormalities in circuit dynamics and behavior in animal models of brain disorders.