The Cerebellar Algorithm

The structure in the mammalian brain most associated with the learning and execution of skilled movements is the cerebellum. After cerebellar damage learned motor skills are lost, and voluntary movements are greatly impoverished with large errors in the force and timing of muscle activity. The importance of the cerebellum may be gauged from its containing as many cells as the rest of the brain put together.

The cerebellum is divided into thousands of modules, each with similar internal micro-circuitry but distinguished by unique connections with other parts of the brain. This leads to the idea of a cerebellar chip, where each chip has similar internal organisation, but its own set of connections, two inputs and one output.

The Cerebellar Chip metaphor
The Cerebellar Chip metaphor.

The cerebellar microcircuit can be mapped onto an adaptive filter structure. The mossy filter inputs are analysed into parallel fibre component signals, which are then weighted and recombined to form the filter (Purkinje cell) output.

The Cerebellum as an Adaptive Filter
The Cerebellum as an Adaptive Filter.

An exciting possibility for the control of autonomous systems is the development of a 'cerebellar chip' controller that could fine tune the control of any task.