字幕表 動画を再生する 英語字幕をプリント [Yawning] Where are my car keys? Hey sleepyheads, Jules here for Dnews! We've all been there. You stay up until 5am studying because you forgot you had a final worth 60% of your grade the next morning. Then, after just an hour or two of sleep, you wander around in a dull haze, like you're drunk or something. Also you fail your final. In fact, being sleep deprived is not altogether different from being drunk, in regards to feeling impaired, and being unable to complete basic tasks. One study from 2000, done by researchers from Australia and New Zealand, took a group of volunteers and kept them from sleeping for up to 28 hours. Then progressively gave them a series of tests, in areas such as cognitive demand, reaction speed, hand-eye coordination, memory, and perception. At another date, they got the same group of participants drunk, first to a blood alcohol level of .05, then to .1, and gave them the same series of tests. The researchers found that at around the 17 to 19-hour sleepless mark, the participants scored similarly to when their blood alcohol level was around 0.05, or slightly worse. Some participants even showed impairment equivalent to 0.1, past the legal drinking limit for driving in the United States of 0.08. What that means is if you stay up late and decide to go for a drive, you are effectively drunk driving. So what's happening in your brain when you're sleep deprived? Well another study from 2000 out of UC San Diego, used fMRIs to look at sleep deprived brains while performing verbal learning tasks. They found that the prefrontal cortex, which is involved in personality, planning, decision making, and social behavior, was working overtime, lighting up much more than it would in the brain of a person who'd had a restful night of sleep. While it may seem counterintuitive, this higher activity is actually a bad thing, since it shows that the brain has to work harder to perform the same tasks. Then they looked at the temporal lobe, which controls your hearing, speech, and vision, as well as long term memory. In sleep deprived subjects, this part of the brain was relatively quiet, when otherwise it would have been lighting up in restful subjects. If you've noticed, sleepy people tend to slur their speech, not unlike drunk people, and for both, that process is related the temporal lobe. Meanwhile, to make up for this lack of activity, the parietal lobe steps in, and while it also deals with sensory input, it doesn't do as good of a job at the specific tasks the temporal lobe deals with. Which is why you are still able to do those tasks, just really really poorly. Clearly, your brain works differently when you're sleepy. Sleep let your brain's neurons rest and regain sensitivity by shutting off your neurotransmitters. To quickly explain: the neurons in your brain are individual cells capable of communicating information using electricity and chemicals. Some of those chemicals are called “neurotransmitters”, including serotonin, dopamine, and histamine. After being bombarded with chemicals all day, your neurons lose sensitivity, which has been proposed as the reason your brain seems to be working more slowly, the more tired you are. Basically, staying up past your bedtime is pretty bad for your cognitive function, and so is drinking. That's pretty scary, because according to Harvard Medical School, roughly a quarter million drivers fall asleep at the wheel every single day. So remember, if you're going to be staying up late, get yourself a designated driver. For more stories that inform you, check out our sister channel Seeker Stories. They recently went to Hawaii to find out how untreated wastewater from cesspools of poop are hurting coral reefs. You can watch the video here. And over on Seeker VR, you can visit the Oceti Sakowin camp at Standing Rock where water protectors are standing strong after their victory against the Dakota Access Pipeline. Watch this video to see the harsh realities that they're facing. Thanks for watching DNews!