ES1 is assumed to be pontine di- or oligosynaptic reflex, ES2 is mediated polysynaptically by inhibitory interneurons probably located in the lateral tegmental field of the brainstem next to the trigeminal nucleus caudalis.

• 对健康者研究表明，ES1为脑桥单或少突触反射所介导，而ES2是由脑干多突触抑制性中间神经元所介导； 介导ES2的这些抑制性中间神经元可能临近三叉神经脊束核尾端的背外侧。