during each of these three periods, eeg data were collected for information on the rats' sleep stages. the mean firing rates of hippocampal place cells during prebehavior sws (pre) and three ten-minute intervals in postbehavior sws (post) were calculated by averaging across 22 track-running sessions from seven rats. the results showed that ten minutes after the trial run session, there was a 12% increase in the mean firing rate of hippocampal place cells from the pre level. after 20 minutes, the mean firing rate returned rapidly toward the pre level. the elevated firing of hippocampal place cells during sws after spatial exploration could explain why there were elevated levels of slow-wave sleep in datta's study, as it also dealt with a form of spatial exploration.