I’m not sure that St. Gregory said that the intellect is “located in the body”, but then I don’t know if I’ve read the exact passage you’re refering to.
I do know that he recommended (along with other “hesychasts”) to focus the mind “in the belly”, but that refers to our control of our bodily (i.e. animal, carnal) impulses, and not to the literal location of the mind per se.
It also refers to us not sending our mind out to think of outside things when reaching to God, but rather to draw inward and be still (or at least give our mind a theological, but non-distracting, focus like the “Jesus Prayer”). When our mind goes out to this or that thing, some idea to think about, it can actually get drawn away from the direct contemplation of God. In Latin terms this would be the difference between meditative and contemplative prayer, the former being thinking about things, though Holy things, and the latter being putting yourself into the direct presence of God without any external focus or “thinking”; the difference between thinking about how God unites Himself to us, and simply experiencing that unity.
I don’t know if any of this directly relates to what you’re refering to, but I hope it helps if it does. If not, would you mind explaining a bit more explicitely what it is you’re talking about?
Peace and God bless!
