Title: Functional Dissection of Movement Signals in Norepinephrine Locus Coeruleus Neurons

The locus coeruleus is a small brainstem nucleus that releases norepinephrine throughout the brain and helps regulate arousal, attention, and learning. One of the most striking features of this system is that its activity is tightly linked to movement, yet it remains unclear what this movement-related signal represents. Does it reflect basic feedback from the moving body, encode movement patterns learned through practice, or combine both types of information?

This project will address that question by combining chronic neural recording, quantitative behavioral analysis, and ultra-flexible neural probe technology. We will record individual norepinephrine neurons in the locus coeruleus while mice learn a skilled sequence-licking task that requires precise tongue and jaw control. In parallel, we will record from jaw muscle spindle afferents in the trigeminal mesencephalic nucleus, a proprioceptive system that may provide direct movement-related input to the locus coeruleus. By following the same neurons across days and weeks, we will distinguish stable movement signals that are present from the outset from signals that emerge during learning.

This work is significant for both scientific and technical reasons. Scientifically, it will clarify how a major brain-wide neuromodulatory system represents movement and adapts to changing movement demands during sensorimotor learning. Technically, it will establish a chronic single-unit recording strategy for deep brainstem circuits that are difficult to access with conventional methods. More broadly, the project will provide a new framework for studying movement-related norepinephrine signaling, reveal how proprioceptive and learned motor signals interact within a neuromodulatory system, and inform broader studies of how the brain coordinates arousal with ongoing action and error correction.