The ground plane of a PCB provides the best return path for the pulsing current on the device layer. Make sure the ground plane is solid, especially the part right underneath the pulsing current paths. Solid copper under a pulsing current path provide a mirrored return path for the high frequency components and minimize voltage spikes generated by the pulsing current. It shields the layers on the other side of the plane from switching noises. Route signal traces on the other side of the ground plane as much as possible. Use multiple vias in parallel to connect the grounds on the device layer to the ground plane.