limbic system does other things than just emotions, its a system of areas with very different functions. amygdala(Amygdala:[3][4][5] Involved in signaling the cortex of motivationally significant stimuli.. - wiki) is the main thing that is involved with creating emotions, and while being part of the limbic system, its also part of temporal lobe(or more precisely is located deep in medial temporal lobe) and has connections to many different areas, which can activate it(and which it obviously needs to be activated).
limbic system is where consciousness is formed and it gets impulses from pretty much all over the brains. basically everything that reaches limbic system(or conscious forming parts of it) from sensory systems or other parts of the brains is differentiated enough to make sense to the conscious mind and what other parts of the brains see as irrelevant are weeded out.
prefrontal cortex also has to do with conscious decision making. i dont really buy this "functions represent different ways of building neurological connections from the frontal cortex back to the limbic area", there are other areas involved in it than just frontal cortex, for example Fe seems to be on temporal lobe(nardis work suggest its on the left hemisphere). however, in order to consciously use Fe, it needs to be used with prefrontal cortex. this is also one thing where i think people mistakenly think the 8 function model is true, because everyone has this area that is involved with social cues etc, but if you dont use it in combination with prefrontal lobes, its not used as a way for decision making, and Fe after all is a decision making function, it basically stops being a rational function(jungs term) and is just one part of perception(irrational function). to be more precise, one aspect of intuition(even jung said that intuition is a peculiar function, because it can basically do the things that other functions would otherwise do, or something like that), as it is perceived through other stuff in the unconscious unconscious, since it doesent connect to conscious decisions making, but is just one part of that pile of the unconscious.
sensation would be a good example of a function that doesent undergo the route from sensory cortexes to frontal lobes and there to limbic system, its basically just when .