Before revision:  Here, we report the tracking performance of the robotic head and show that the robotic eye kinematics are similar to those reported in human eye studies  .
After revision:  Here, we report the tracking performance of the robotic head and show that the robotic eye kinematics are similar to those reported in human eye studies and show that a biologically-constrained learning, although not required for the SNN's function, can be used to further refine its performance .