The answer to this question is clearly yes. One can understand that for behavior to occur there needs to be three things: a permeability change in the membrane, a concentration gradient and a passive current flow. The onset of this can occur by molecules triggering nerve endings or it is also autonomous. The path in which the potential follows and where it goes depends on what the molecule was and what changes that molecule caused. This explains a lot because molecules float all around us, they are detected through the scent, the touch, hearing and sight. The brain registers each of these behaviors in a different location with different paths of potentials and different firing even though the underlining process is the same. So, yes behavior is better understood, but one question remains. While, running the other day, I became tired, but I had about 600 meters left, I don't recall consciously (for lack of a better word) choosing to run faster, I felt exhausted but my pace grew increasingly faster. Now I understand what causes my legs to move in order to run, but the inputs to my system were constant, so what causes the slight change in my "behavior" for me to run faster. Why was a neurotransmitter (like adrenline) released, if this is what caused it? I understand the action potential was firing more rapidly but what cause it to do so?

Nice question. IF inputs constant, then change must have originated within the nervous system. Perhaps an endogenous thought? Changes in action potentials must be because of changes in action potentials, which might be due to sensory input or to things going on within neurons themselves, yes? Is the origin of the latter which bothers you? Won't have more time for that in this course, but there are lots of possible explanations if you'd like to read more (or take some more neuroscience courses). PG