Penn Team Discovers How Muscle-Controlling Neurons Know When They Make Mistakes

The brain orchestrates precise control over the body’s muscles through neurons known as Purkinje cells. When those movements go wrong, the body provides feedback from the senses through another type of neuron called climbing fibers. These work in close concert with Purkinje cells to fine-tune motor control. A team of researchers from the University of Pennsylvania and Princeton University has now begun to unravel the mysteries of how this feedback system works.

Although climbing fibers send signals to Purkinje cells when there is an error to report, they also fire spontaneously about once a second. There did not seem to be any mechanism by which individual Purkinje cells could detect a legitimate error signal from within this noise of random firing. 

Using a microscopy technique that allowed the researchers to directly visualize the chemical signaling occurring between the climbing fibers and Purkinje cells of live, active mice, the Penn team has for the first time shown that there is a measurable difference between “true” and “false” signals.

This knowledge will be fundamental to future studies of fine motor control, particularly with regards to how movements can be improved with practice. 

The research, published in the journal Cell Reports, was conducted by Javier Medina, an assistant professor in the Department of Psychology, and Farzaneh Najafi, a graduate student in the Department of Biology. They collaborated with postdoctoral fellow Andrea Giovannucci and associate professor Samuel S. H. Wang of Princeton University.

Their work was supported by the National Institutes of Health, the New Jersey Commission on Brain Injury Research and the Searle Scholars Program.

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