对头皮记录所获的远电场N_(18)和近电场N_(20)电位的变异,很多人推测可能起源于一种“发生器”。对于N_(18)电位,最初的报导推测为是丘脑即丘脑——皮层的扩散和位于脑干的某些结构。此后的报导均认为是脑干源性的。有一家报导,利用头皮记录一位长期大脑半球切除的病人,提示在中脑存在有一个“发生器”;另一个研究利用颅内记录,提示“发生器”位于脑桥上部或中脑下部。最近在磁共振 Scalp recorded far-field N_ (18) and near-field N_ (20) potential variability, many people speculated that may originate from a “generator.” For the N_ (18) potential, the initial report presumed to be the thalamus, the thalamic-cortex diffusion and some structures located in the brainstem. Subsequent reports are considered stem-derived. In one report, scalp recording of a patient with a long-term hemisphere excision prompted the presence of a “generator” in the midbrain; another study utilized intracranial recordings suggesting that the “generator” was located in the upper or middle part of the midbrain. Recently in magnetic resonance