With finals just around the corner, a University of Wisconsin professor and researcher specializing in psychiatry discussed some of the mysteries surrounding sleep — and also its importance — on campus Tuesday. During his lecture "Sleep: A Window to the Brain," psychiatry professor Giulio Tononi explained the value of sleep, as well as the ineffectiveness of late-night cramming sessions. "Sleep would be a very good way to look at consciousness, because when you fall asleep early in the night, consciousness fades in most of us," Tononi said. "It happens every night, and it happens in everyone." Tononi said researchers still have no idea why humans — or any species for that matter — sleep, and noted that scientists have been seeking answers for 2,000 years. "Sleep remains to be one of the areas of biology yet to be solved, so it's interesting in its own right," Tononi said. Although many theories exist, Tononi said humans sleep as a way of "taking care of downsizing." "By the morning, you haven't lost the memory," Tononi said. "But everybody's [brain] gets a little bit leaner, so the brain consumes less energy, less space, less supplies and is ready to learn again." Some believe that sleep is used for memory conservation, Tononi said, while others think sleep is meant to restore the body and the brain. Regardless, "everyone feels restored after they sleep," he said. Tononi also explained the inefficiency of late-night cramming sessions. "It's bad hygiene to sleep little and to cram all the studies toward the end," Tononi said. "That fits with the hypothesis that if you saturate your ability to learn — if you don't sleep over it — then you can't learn anew." There are numerous reasons getting little sleep can be detrimental to educational success, Tononi said, especially during finals. "Sleep actually helps consolidating several memories," Tononi said. "The fact that if you don't sleep or you sleep a little, your ability to remember the next day is going to be impaired." Tononi said that late-night cramming will not only shorten students' abilities to retain information for an extended period of time, but also hinder their abilities to learn new knowledge the next day. Professor Ronald Kalil, of the UW School for Medicine and Public Health, who introduced Tononi, said the lecture was "outstanding" and reiterated how little scientists know about something people do every day, despite "decades of work and research." "Everyone knows that they have to sleep — some less than others — but there's never been an example of an individual that didn't have to sleep," Kalil said. "It's something that we have to do, and we want to figure out way." Kalil said it is human nature to desire answers to such a mystery of life. "If you have to do something, you'd like to know what the biological basis for it is," Kalil said.