There is a compact bundle of fibres extending longitudinally through the medulla oblongata’s posterolateral region known as the solitary tract (ST). A variety of reflexes that control cardiovascular function, respiration, and gastrointestinal motility originate at ST as the first relay station for cranial nerve effects, such as visceral and taste afferents.
So the answer is YES. ST and NTS have an obvious border, and we can see nuclei in the middle of myeline fibres after labeling ST with Ki67 and CNPase.