Though so far unexplained, the observation that a nociceptive stimulus delivered at the paw level is associated with NTC activation is further reported by the study of Han et al., [46], which showed that formalin injection in the paw induces Fos expression in NTC, and in other brainstem areas (i.e locus coeruleus) known to be involved in the modulation of migraine pain [47]. This evidence concerns the gene FOS and migraine disorder.