Segway Cerebellum

The Segway BBD and its environment. A. The BBD is built on the Segway Robotic Mobility Platform. The device navigated a path dictated by the orange traffic cones that were spaced apart by a few inches. B. The diagram shows the layout of the different courses. The lane dictated by the cones was five feet wide and roughly 25 feet long. The device itself was approximately two feet in diameter.

The cerebellum is known to be critical for accurate adaptive control and motor learning. We have proposed a novel mechanism by which the cerebellum may replace reflex control with predictive control, which we call a "preflex". This mechanism is embedded in a learning rule (the delayed eligibility trace rule) in which synapses onto a Purkinje cell or onto a cell in the deep cerebellar nuclei become eligible for plasticity only after a fixed delay from the onset of suprathreshold presynaptic activity. To investigate the proposal that the cerebellum is a general-purpose predictive controller guided by a delayed eligibility trace rule, a computer model based on the anatomy and dynamics of the cerebellum was constructed. It contained components simulating cerebellar cortex and deep cerebellar nuclei, and it received input from a cortical area MT and the inferior olive. The model was incorporated in a real-world brain-based device (BBD) built on a Segway robotic platform that learned to traverse curved paths. The BBD learned which visual motion cues predicted impending collisions and used this experience to avoid path boundaries. During learning, it adapted its velocity and turning rate to successfully traverse various curved paths. By examining neuronal activity and synaptic changes during this behavior, we found that the cerebellar circuit selectively responded to motion cues in specific receptive fields of simulated area MT. The system described here prompts several hypotheses about the relationship between perception and motor control and may be useful in the development of general-purpose motor learning systems for machines.

Click here for a video of the Segway Cerebellum Brain-Based-Device before learning.

Click here for a video of the Segway Cerebellum Brain-Based-Device after learning.

For further information see this paper.