It is also significant that Galen equates Plato’s logistikon (“rational”) with the hēgemonikon (“leading-part”): the concepts are (in origin at least) distinct and derive from different conceptions of the soul. The latter is a Stoic term, although probably also prominent in the Hellenistic medical authors just mentioned: it is the notion of a single “command centre” for the soul, which communicates to the rest of the body, both receiving the information of the different sense organs and giving the command (in Stoic language, the assent) for voluntary actions. Such a single command centre is not (at least explicitly) present in Plato; similarly, such a physically centralized psychic concept is at best vaguely present in Aristotle.