Background: Transsynaptic tracing of acupoints has been performed for many acupoints.Aim: We discuss brainstem neurophysiological effects of anatomical substrates reached by the secondary afferent.Relevance: Dorsal horn projection neurons form the spinoreticular tract.The slow nociceptive signals project directly to reticular subnuclei of the btrainstem, the fast signals as collaterals of spinothalamic-or spinocerebellar pathways.The transsynaptic tracer can be immunostained in apposition of the third order neurons, which explain patterned medicine.Integrative target neurons in the brainstem of third order are two synapses away from the receptive cutaneous field.Conclusion: Wide Dynamic Range neurons (lamina5), combine convergent multimodal afference with premotor efference to the intermediolateral-or the somatomotor horn, accounting for segmental indications.The divergence, of the spinoreticular arborizations of the secondary afferent, accounts for the hetereogeneity of acupoint indications.The integrative functions of the subnuclei of the reticular formation transcend the locoregional level, forming lower pattern generators.These are controlled by the PAG under modulation of subcortical-or cortical centers.