Since this thread began with a modern science topic, it might be pertinent to mention Lisa Feldman Barrett. As I understand it she seems to consider "affect" to be a type of guiding faculty. She pictures affect as a combination of pleasant/unpleasant along, say, an x axis, and calmness/agitation along, say, a y axis. One's affect at a given moment would be described by a point somewhere in the two dimensional space defined by these two axes.
I find this conception useful because it illustrates 1) that "pleasure" isn't the endpoint of an arrow or the center of a target but a combination of factors including pleasantness and arousal. And 2) calmness combined with unpleasantness would be considered lethargy (or something similar). When people speak of "without pain" or "without disturbance" and interpret those as pleasure, I think it helps to look at this 2D model to understand more of the nuance involved.
So LFB, as I recall, refers to positive or negative affect as a neurological guide which we might be able to equate to pleasure or pain. Although hers isn't the language of Epicurus, I find it a helpful way to understand pleasure as the guide/goal.