The correlation coefficients (corMU) between all pairs of 57 MU firing patterns for the NS model and for the four methods of MU synchronization using Δt ± 6 ms.

The color map represents corMU values in the range of 0% to 100% calculated within the square grid (57 × 57) of sequential MU numbers from 1 to 57. The diagonal elements of the color map correspond to a 100% correlation between the firing pulses of identical MUs.