Spiking activity of the afferent neural populations. The first column reports the raster plots and the second column the corresponding population rate-based signals (computed with time bins of 25 ms). (A) Sensory feedback subpopulation neurons (encoding the movement along the x-axis) (prelearning ≈ postlearning). While the negative group shows a constant background firing rate (approximately 50 Hz), the positive group generates a number of spikes that depend on the progressive moving away of the point mass along the x-axis from the starting point toward the desired target. The difference in firing rate between positive and negative groups encodes the actual position profile, which ranges from 0 to 1 m (dashed black line). (B) Cerebellar output subpopulation neurons (encoding the movement along x-axis) in prelearning. Both groups show a constant background firing rate (∼50 Hz); therefore, the net activity does not encode any relevant information. (C) Cerebellar output subpopulation neurons (encoding the movement along the x-axis) in postlearning. While the negative group shows a constant background firing rate (about 50 Hz), the positive group generates a number of spikes that depend on the progressive moving away of the point mass along the x-axis, from the starting point toward the desired target. The net activity encodes the predicted position profile, which ranges from 0 to 1 m (dashed black line). Note that this predicted position (“planned trajectory”) (given as the analog input to the cerebellar output neurons in postlearning) anticipates by 100 ms the actual position (“executed trajectory”), given as analog input to the sensory feedback neurons).