Everyone else has realized that both happen depending on how that particular part of the nervous system works, or even what particular kind of information is flowing through it.
This title reads like it was written by a rate coder who woke up one day and was like "Woah, you mean ... there might be more to it than just averaging spike counts per unit time???"
edit: Hah, they are literally the first two headings in the wikipedia article on neural coding [0].