Population coding in the cerebellum

5:00pm - 6:30pm
College Hall 2
Speakers Website
Dr. Reza Shadmehr

A slow sensory system presents major problems for movement control. Yet, despite this shortcoming the healthy brain composes exquisite movements. Textbooks posit that this remarkable ability is due to the cerebellum, a structure that learns to predict sensory consequences, thus overcoming time delays. However, in the cerebellum, the neuronal activity is modulated long after the movement has ended. Thus, the language with which the cerebellum expresses its predictions has remained a mystery. Here, the idea that we have explored is that in the cerebellum, the fundamental unit of computation may not be a single neuron, but a group of neurons that share the same teacher. In this analogy, the teacher is the inferior olive, organizing the students (Purkinje cells) into groups. To test this idea, we have measured activity of neurons in macaques and marmosets and found that while activity of individual neurons is difficult to decipher, activity of a group of neurons that shares the same teacher is a rather precise predictor of the ongoing movement, particularly during deceleration and stopping.


Martijn Schonewille