State estimator design. (A) Sensory reafferences from periphery and cerebellum project to the state estimator block, which in turn generates the optimal state signal. (B) Spiking architecture of the system. Each state estimator neuron (blue) receives spikes from sensory feedback and cerebellar output neurons. It stores the spikes into two separate buffers, counts the number of input spikes from each presynaptic neuron, and computes the “instantaneous” variability of each afferent population.