C4B and cyclic hematopoiesis: Here, we further demonstrated, not only in urethane, but also in CH, that no reflexive withdrawal to a hind-paw pinch was observed in either the activated or the deactivated brain state, and furthermore, that bolus infusions or metabolism of urethane or CH did not alter the periodicity of brain-state alternations, only the proportion of time spent in either the activated or deactivated state per cycle.