Next-Generation Tools to Measure and Manipulate Muscle Activity Across Species and Behaviors

Despite recent advances in technology for recording and modulating neural activity, current methods for measuring and manipulating the nervous system’s motor output lag far behind in terms of scale and resolution. The control of skeletal motor output is mediated by “motor units”, each consisting of a single motor neuron and the muscle fibers it activates to generate muscle force and produce body movements. Because each “spike” (action potential) in a motor neuron reliably evokes a single spike in its target muscle fibers, spikes recorded from muscle provide high-resolution readouts of motor neuron activity in the central nervous system. However, traditional methods for recording EMG in experimental animals (fine-wire EMG) are typically unable to resolve the activity of individual motor units and can only be applied to a small number of relatively large and easily accessible muscles. Moreover, although both electrical and optogenetic methods can be used to modulate sensorimotor activity in the periphery, we presently lack tools for combining high-resolution muscle recording with precision manipulation of motor activity or the sensory signals that powerfully modulate motor output. In the initial funded period of this grant, we created a new generation of electrode devices (“Myomatrix arrays”) for recording muscle activity at unprecedented resolution in mice and songbirds. Here we propose to build on these successes by creating novel sensor designs optimized for recording from a wide range of species, body sizes, and muscle types. Additionally, we will create technologies for combining high-resolution sensing with simultaneous manipulations of sensory and motor signals in the peripheral nervous system. Finally, in addition to creating these new technologies we will pioneer novel fabrication methods that enable low-cost production of these technologies, ensuring their wide availability to the neuroscience community.