1 00:00:02,189 --> 00:00:04,578 For centuries, we've regarded sleep 2 00:00:04,578 --> 00:00:08,745 as nothing more than a way to recharge our batteries. 3 00:00:09,641 --> 00:00:11,974 But all of that is changing. 4 00:00:13,066 --> 00:00:14,849 If sleep wasn't important, 5 00:00:14,849 --> 00:00:18,634 it is probably one of the most significant mistakes 6 00:00:18,634 --> 00:00:21,426 that evolution ever made. 7 00:00:21,426 --> 00:00:23,493 Once seen as a blank screen, 8 00:00:23,493 --> 00:00:25,594 the sleeping brain is now emerging 9 00:00:25,594 --> 00:00:29,025 as an energetic and purposeful machine. 10 00:00:29,025 --> 00:00:32,100 In parts of sleep, the brain is at least as active 11 00:00:32,100 --> 00:00:35,869 and maybe more active than it is during waking. 12 00:00:35,869 --> 00:00:36,807 Around the world, 13 00:00:36,807 --> 00:00:39,230 researchers are attempting to penetrate 14 00:00:39,230 --> 00:00:41,463 the mysterious world of sleep 15 00:00:41,463 --> 00:00:43,584 and decipher its secrets. 16 00:00:43,584 --> 00:00:46,584 Secrets that could change our lives. 17 00:00:47,528 --> 00:00:49,538 I think that what happens during sleep 18 00:00:49,538 --> 00:00:53,336 permits what happens in the waking brain. 19 00:00:53,336 --> 00:00:55,262 I'm Doctor Jennifer Gardy. 20 00:00:55,262 --> 00:00:57,929 Join me on a surprising odyssey. 21 00:00:58,822 --> 00:01:00,134 This is remarkable. 22 00:01:00,134 --> 00:01:03,342 (laughs) Wow. 23 00:01:03,342 --> 00:01:07,605 From playing Chopin to playing with puppets. 24 00:01:07,605 --> 00:01:11,036 From a city that never sleeps to an isolation chamber 25 00:01:11,036 --> 00:01:13,218 in the Colorado Rockies, 26 00:01:13,218 --> 00:01:16,693 come with me as I begin a journey to discover 27 00:01:16,693 --> 00:01:17,776 why we sleep. 28 00:01:20,584 --> 00:01:23,334 (dramatic music) 29 00:01:31,432 --> 00:01:33,318 Deep in the German countryside 30 00:01:33,318 --> 00:01:37,485 lies one of the unique research centers in the world. 31 00:01:39,553 --> 00:01:42,369 Inside this compound, scientists uncovered 32 00:01:42,369 --> 00:01:44,928 one of the first clues that sleep 33 00:01:44,928 --> 00:01:48,928 might be about more than just conserving energy. 34 00:01:49,818 --> 00:01:50,651 That's very nice. 35 00:01:50,651 --> 00:01:53,238 Doctor Niels Rattenborg has spent a decade 36 00:01:53,238 --> 00:01:56,541 researching here at the Max Planck Institute. 37 00:01:56,541 --> 00:02:00,228 But he isn't your typical sleep scientist. 38 00:02:00,228 --> 00:02:04,300 That's because Dr. Rattenborg doesn't study humans, 39 00:02:04,300 --> 00:02:06,086 he studies birds. 40 00:02:06,086 --> 00:02:07,724 (flapping wings) 41 00:02:07,724 --> 00:02:09,402 Birds are an excellent group of animals 42 00:02:09,402 --> 00:02:11,731 in which to study sleep, because they've evolved 43 00:02:11,731 --> 00:02:14,108 sleep patterns remarkably similar 44 00:02:14,108 --> 00:02:17,525 to those in mammals, including ourselves. 45 00:02:21,562 --> 00:02:23,299 While all animals sleep, 46 00:02:23,299 --> 00:02:26,054 scientists like Dr. Rattenborg now know 47 00:02:26,054 --> 00:02:29,242 that only birds have slow wave and REM sleep 48 00:02:29,242 --> 00:02:30,325 just like us. 49 00:02:32,307 --> 00:02:35,825 It's why he's studying the humble Canada goose. 50 00:02:35,825 --> 00:02:36,768 (honk) 51 00:02:36,768 --> 00:02:38,548 A bird that helped him understand 52 00:02:38,548 --> 00:02:41,479 what evolution revealed about sleep. 53 00:02:41,479 --> 00:02:42,312 Some geese over here. 54 00:02:42,312 --> 00:02:43,145 Yeah. 55 00:02:43,145 --> 00:02:44,443 And he wanted me to demonstrate 56 00:02:44,443 --> 00:02:47,703 what he was the first to discover. 57 00:02:47,703 --> 00:02:49,289 So, you see those geese sleeping? 58 00:02:49,289 --> 00:02:50,122 Yeah. 59 00:02:50,122 --> 00:02:53,205 You think you can sneak up on them? 60 00:02:57,505 --> 00:02:59,035 Seems pretty easy. 61 00:02:59,035 --> 00:03:01,368 Sleeping geese, smart human. 62 00:03:03,153 --> 00:03:05,820 (playful music) 63 00:03:14,906 --> 00:03:17,028 They're starting to look. 64 00:03:17,028 --> 00:03:21,306 But these geese prove far more elusive than I expect. 65 00:03:21,306 --> 00:03:23,849 Whenever I get too close, they wake up 66 00:03:23,849 --> 00:03:25,766 and head for the hills. 67 00:03:26,693 --> 00:03:28,900 I give up, it's impossible! 68 00:03:28,900 --> 00:03:30,535 Some already went back to sleep. 69 00:03:30,535 --> 00:03:32,637 (both laugh) 70 00:03:32,637 --> 00:03:34,442 According to Dr. Rattenborg, 71 00:03:34,442 --> 00:03:38,609 the geese evaded me because of an amazing feat of evolution. 72 00:03:42,506 --> 00:03:46,009 It's called unihemispheric sleep. 73 00:03:46,009 --> 00:03:49,473 Whales, seals, and dolphins do it, too. 74 00:03:49,473 --> 00:03:52,842 While one half of the brain stays awake and alert, 75 00:03:52,842 --> 00:03:54,421 and one eye open, 76 00:03:54,421 --> 00:03:57,653 the other side of the brain is in deep sleep 77 00:03:57,653 --> 00:04:00,653 and the corresponding eye is closed. 78 00:04:01,499 --> 00:04:04,904 Given this extraordinary evolutionary adaptation, 79 00:04:04,904 --> 00:04:07,355 Dr. Rattenborg believes that what's happening 80 00:04:07,355 --> 00:04:11,522 inside the sleeping brain must be vital to life itself. 81 00:04:13,463 --> 00:04:15,046 And he's not alone. 82 00:04:20,208 --> 00:04:21,041 Yeah. 83 00:04:23,572 --> 00:04:27,653 Dr. Sabine Seehagen often spends more time on the road 84 00:04:27,653 --> 00:04:31,820 than in her lab at Ruhr University in Western Germany. 85 00:04:33,782 --> 00:04:35,785 That's because her research subjects 86 00:04:35,785 --> 00:04:39,952 have evolved to spend more time asleep than awake. 87 00:04:40,900 --> 00:04:44,043 Babies nap for up to 16 hours a day 88 00:04:44,043 --> 00:04:48,210 with waking periods lasting for just an hour or two. 89 00:04:49,715 --> 00:04:51,809 From the bird research, it was clear 90 00:04:51,809 --> 00:04:55,059 that sleep was playing some vital role. 91 00:04:55,059 --> 00:04:57,803 Dr. Seehagen wanted to find out if it was 92 00:04:57,803 --> 00:05:01,720 helping babies consolidate and retain memories. 93 00:05:03,493 --> 00:05:05,147 Infants, they have to learn so much 94 00:05:05,147 --> 00:05:06,449 in the first few years of life 95 00:05:06,449 --> 00:05:09,238 and they develop in such striking ways, really, 96 00:05:09,238 --> 00:05:10,071 everyday a bit more. 97 00:05:10,071 --> 00:05:11,861 (baby exclaiming) 98 00:05:11,861 --> 00:05:15,074 We were interested to see whether one function of sleep 99 00:05:15,074 --> 00:05:18,680 might be to facilitate memory processing. 100 00:05:18,680 --> 00:05:20,694 To discover that, Dr. Seehagen 101 00:05:20,694 --> 00:05:23,571 chooses a task that requires baby Moritz 102 00:05:23,571 --> 00:05:26,654 to remember three interrelated steps. 103 00:05:28,490 --> 00:05:29,683 We use a hand puppet 104 00:05:29,683 --> 00:05:32,196 and show them three actions. 105 00:05:32,196 --> 00:05:35,446 We throw them how to take off a mitten, 106 00:05:36,609 --> 00:05:38,609 how to shake the mitten, 107 00:05:41,898 --> 00:05:44,815 and then how to replace the mitten. 108 00:05:46,038 --> 00:05:47,995 What Dr. Seehagen is attempting to do 109 00:05:47,995 --> 00:05:51,328 is trigger the memory processing system. 110 00:05:56,284 --> 00:06:00,374 The hippocampus is located deep within our brain. 111 00:06:00,374 --> 00:06:04,541 This is where specific memories are encoded and stored. 112 00:06:06,086 --> 00:06:09,676 The neocortex is the large, outer part of our brain. 113 00:06:09,676 --> 00:06:13,426 It establishes associations between memories. 114 00:06:16,831 --> 00:06:19,427 Dr. Seehagen and her assistant, Carol, 115 00:06:19,427 --> 00:06:22,610 teach the exact same memory processing task 116 00:06:22,610 --> 00:06:24,610 to several other babies. 117 00:06:29,507 --> 00:06:32,340 (speaking German) 118 00:06:36,610 --> 00:06:38,537 As soon as the testing is over, 119 00:06:38,537 --> 00:06:41,326 some of the babies stay awake, 120 00:06:41,326 --> 00:06:43,699 while others, like baby Moritz, 121 00:06:43,699 --> 00:06:45,199 go down for a nap. 122 00:06:48,618 --> 00:06:51,605 For Dr. Seehagen, this is a rare opportunity 123 00:06:51,605 --> 00:06:53,872 to discover whether the sleeping brain 124 00:06:53,872 --> 00:06:56,469 is doing something unique with the information 125 00:06:56,469 --> 00:06:58,052 it's just taken in. 126 00:06:59,973 --> 00:07:02,988 We were thinking that if sleep really helps them 127 00:07:02,988 --> 00:07:04,348 to retain the memories, 128 00:07:04,348 --> 00:07:07,800 then only those infants who napped right away, 129 00:07:07,800 --> 00:07:10,498 soon after learning, would remember the actions. 130 00:07:10,498 --> 00:07:12,823 Whereas infants who would wait with their nap 131 00:07:12,823 --> 00:07:15,406 would not remember the actions. 132 00:07:20,243 --> 00:07:24,233 Carla hasn't had a chance to nap yet. 133 00:07:24,233 --> 00:07:27,182 Like all of the babies, she has just 90 seconds 134 00:07:27,182 --> 00:07:29,643 to repeat the action she saw earlier. 135 00:07:29,643 --> 00:07:32,226 (Carla cooing) 136 00:07:38,977 --> 00:07:43,144 But Carla shows no sign of remembering the three steps. 137 00:07:48,499 --> 00:07:50,687 (doorbell chimes) 138 00:07:50,687 --> 00:07:54,020 Jonah is another baby who hasn't napped. 139 00:07:59,787 --> 00:08:01,339 Before we started our study there was not 140 00:08:01,339 --> 00:08:03,752 very much knowledge about how sleep 141 00:08:03,752 --> 00:08:06,294 might be important for infants' memories 142 00:08:06,294 --> 00:08:08,396 and I'm very interested to see 143 00:08:08,396 --> 00:08:10,890 that infants who wait with the nap, 144 00:08:10,890 --> 00:08:13,535 they did not show signs of remembering 145 00:08:13,535 --> 00:08:15,952 what we've shown them before. 146 00:08:22,422 --> 00:08:25,262 Across town, baby Moritz is just up 147 00:08:25,262 --> 00:08:27,620 from his four hour nap. 148 00:08:27,620 --> 00:08:29,120 Now it's his turn. 149 00:08:31,851 --> 00:08:35,101 Without any prompting, he gets to work. 150 00:08:42,436 --> 00:08:43,519 And nails it. 151 00:08:44,687 --> 00:08:46,739 (speaks German) 152 00:08:46,739 --> 00:08:49,787 Dr. Seehagen and her colleagues conducted this test 153 00:08:49,787 --> 00:08:51,787 on more than 200 infants 154 00:08:53,105 --> 00:08:55,022 with identical results. 155 00:08:56,464 --> 00:08:58,766 Well, I think it shows several amazing things 156 00:08:58,766 --> 00:09:00,401 about babies, actually. 157 00:09:00,401 --> 00:09:01,613 Until a few decades ago, 158 00:09:01,613 --> 00:09:03,252 many people even doubted whether infants 159 00:09:03,252 --> 00:09:06,125 can form longer term memory. 160 00:09:06,125 --> 00:09:08,031 But I think our study shows that sleep 161 00:09:08,031 --> 00:09:10,507 seems to play a really fundamental role 162 00:09:10,507 --> 00:09:12,945 in early memory processing. 163 00:09:12,945 --> 00:09:16,237 And I mean, that's a very fundamental task for infants 164 00:09:16,237 --> 00:09:19,515 to build long term memories so that they can 165 00:09:19,515 --> 00:09:21,682 use them at a later point. 166 00:09:26,353 --> 00:09:29,186 (classical piano) 167 00:09:35,209 --> 00:09:37,008 George Ko is in the midst of a 168 00:09:37,008 --> 00:09:39,953 Harvard University tradition. 169 00:09:39,953 --> 00:09:41,191 He's cramming. 170 00:09:41,191 --> 00:09:44,024 (classical piano) 171 00:09:51,371 --> 00:09:54,691 George is trying to learn Chopin's third Scherzo, 172 00:09:54,691 --> 00:09:57,108 but he's running out of time. 173 00:09:58,439 --> 00:10:01,823 So this week I got slammed with a lot of work 174 00:10:01,823 --> 00:10:03,730 and I have a performance tomorrow 175 00:10:03,730 --> 00:10:07,147 and I haven't been able to practice much. 176 00:10:08,522 --> 00:10:12,667 For George, the solution is a no-brainer. 177 00:10:12,667 --> 00:10:14,762 So I'm probably not going to sleep tonight. 178 00:10:14,762 --> 00:10:19,590 I'm probably going to hear the birds chirp in the morning. 179 00:10:19,590 --> 00:10:22,338 But if babies need sleep to process memories 180 00:10:22,338 --> 00:10:26,505 and learn, is the same true for adults like George Ko? 181 00:10:30,865 --> 00:10:33,115 (birdsong) 182 00:10:37,887 --> 00:10:40,939 Jen, why don't we put you over here and Jamai, you... 183 00:10:40,939 --> 00:10:42,830 It's a question that drives the research 184 00:10:42,830 --> 00:10:45,493 of Doctor Robert Stickgold. 185 00:10:45,493 --> 00:10:47,877 A really simple test for you guys to do. 186 00:10:47,877 --> 00:10:50,423 Dr. Stickgold is one of the world's leading 187 00:10:50,423 --> 00:10:52,052 sleep scientists. 188 00:10:52,052 --> 00:10:54,749 So, put in your first name or your initials. 189 00:10:54,749 --> 00:10:56,770 To discover whether memory processing 190 00:10:56,770 --> 00:10:58,488 is sleep dependent, 191 00:10:58,488 --> 00:11:01,518 Dr. Stickgold needs to create a complex learning 192 00:11:01,518 --> 00:11:03,181 and motor skill task. 193 00:11:03,181 --> 00:11:05,320 Now, as soon as you press another key you're gonna start. 194 00:11:05,320 --> 00:11:08,452 What he decides on is a very simplified version 195 00:11:08,452 --> 00:11:11,256 of performing Chopin's Third Scherzo. 196 00:11:11,256 --> 00:11:12,556 And your job, take your left hand, 197 00:11:12,556 --> 00:11:16,585 put your four fingers on the keys one, two, three, and four. 198 00:11:16,585 --> 00:11:18,517 You're just gonna type that number sequence 199 00:11:18,517 --> 00:11:22,430 over and over again, four one three two four. 200 00:11:22,430 --> 00:11:26,597 Why don't we just have you both start together now? 201 00:11:27,665 --> 00:11:30,041 Both Jamai and I are going to do this task 202 00:11:30,041 --> 00:11:33,450 a second time, but I'll get to sleep in between 203 00:11:33,450 --> 00:11:34,736 and she won't. 204 00:11:34,736 --> 00:11:37,406 Then we'll see who has the bigger improvement 205 00:11:37,406 --> 00:11:39,239 in speed and accuracy. 206 00:11:47,285 --> 00:11:50,365 It seems hard to believe that just one night of sleep 207 00:11:50,365 --> 00:11:53,855 will help me learn the sequence and make me faster. 208 00:11:53,855 --> 00:11:55,772 But tomorrow will tell. 209 00:12:03,762 --> 00:12:06,448 The next morning, I'm back. 210 00:12:06,448 --> 00:12:09,642 Jamai did her retest yesterday afternoon. 211 00:12:09,642 --> 00:12:11,059 Now it's my turn. 212 00:12:15,020 --> 00:12:18,603 It all comes down to who has improved more. 213 00:12:30,325 --> 00:12:32,634 And here you are. 214 00:12:32,634 --> 00:12:33,640 Let's take a look at this. 215 00:12:33,640 --> 00:12:34,915 Okay. 216 00:12:34,915 --> 00:12:37,597 First, Jamai's results. 217 00:12:37,597 --> 00:12:39,882 On her second trial with no sleep, 218 00:12:39,882 --> 00:12:43,361 look at here, she's shown no improvement at all. 219 00:12:43,361 --> 00:12:46,342 But I was a different story. 220 00:12:46,342 --> 00:12:48,592 Then look at this, you just zoom up there. 221 00:12:48,592 --> 00:12:50,268 You're up to 23. 222 00:12:50,268 --> 00:12:53,768 It's a huge improvement in terms of speed. 223 00:12:54,967 --> 00:12:57,033 It's not just academics and students 224 00:12:57,033 --> 00:12:58,460 who are learning all the time. 225 00:12:58,460 --> 00:13:00,470 We're all learning all the time. 226 00:13:00,470 --> 00:13:02,519 Every time you start your car, 227 00:13:02,519 --> 00:13:03,946 you're learning a little bit more about 228 00:13:03,946 --> 00:13:05,828 how long you have to turn the key, 229 00:13:05,828 --> 00:13:07,491 how much you have to press the gas. 230 00:13:07,491 --> 00:13:09,717 Every time you turn a corner, 231 00:13:09,717 --> 00:13:13,027 you're retooling your accuracy at doing that. 232 00:13:13,027 --> 00:13:17,941 So we're learning all the time and we don't even know it. 233 00:13:17,941 --> 00:13:19,788 When we sleep after learning, 234 00:13:19,788 --> 00:13:21,938 our brain consolidates that memory 235 00:13:21,938 --> 00:13:24,198 so we can retrieve it easily. 236 00:13:24,198 --> 00:13:26,499 The more complex the learning task, 237 00:13:26,499 --> 00:13:29,875 the bigger the benefit we get from sleep. 238 00:13:29,875 --> 00:13:32,069 But when we don't sleep enough 239 00:13:32,069 --> 00:13:35,721 that information never even gets filed. 240 00:13:35,721 --> 00:13:38,317 If you don't get enough sleep 241 00:13:38,317 --> 00:13:40,341 the night after you've learned, 242 00:13:40,341 --> 00:13:45,211 you are not going to show the potential benefits from sleep. 243 00:13:45,211 --> 00:13:48,537 Even if you sleep all you want for the rest of the week. 244 00:13:48,537 --> 00:13:50,971 It has to come in that first night. 245 00:13:50,971 --> 00:13:53,494 So what we're learning is that night by night 246 00:13:53,494 --> 00:13:56,079 we need that sleep or we'd lose. 247 00:13:56,079 --> 00:13:57,829 We'd lose everything. 248 00:13:59,533 --> 00:14:02,366 (classical piano) 249 00:14:15,529 --> 00:14:16,961 I'm not the only one who benefited 250 00:14:16,961 --> 00:14:18,730 from some shuteye. 251 00:14:18,730 --> 00:14:20,465 Instead of pulling an all-nighter, 252 00:14:20,465 --> 00:14:22,298 George Ko went to bed. 253 00:14:26,243 --> 00:14:28,523 According to Dr. Stickgold's research, 254 00:14:28,523 --> 00:14:31,606 it was exactly the right thing to do. 255 00:14:33,868 --> 00:14:36,060 When I tell people that we learn a lot 256 00:14:36,060 --> 00:14:40,427 while we're asleep, they think that's kind of an oxymoron, 257 00:14:40,427 --> 00:14:43,021 that you can't learn while you're asleep. 258 00:14:43,021 --> 00:14:45,133 But in fact, this is just your brain 259 00:14:45,133 --> 00:14:47,466 doing what it evolved to do. 260 00:14:48,734 --> 00:14:51,864 I think the brain carries out its most sophisticated 261 00:14:51,864 --> 00:14:56,185 memory and brain functions while we sleep. 262 00:14:56,185 --> 00:14:59,018 (classical piano) 263 00:15:07,598 --> 00:15:09,848 (seagulls) 264 00:15:11,997 --> 00:15:14,945 Given the power of sleep to help us learn, 265 00:15:14,945 --> 00:15:18,492 scientists at a unique biosphere in Colorado 266 00:15:18,492 --> 00:15:22,706 wondered whether it also had the capability to control 267 00:15:22,706 --> 00:15:24,039 how much we eat. 268 00:15:25,644 --> 00:15:28,561 (electronic music) 269 00:15:31,432 --> 00:15:34,653 What better place to find out why we sleep 270 00:15:34,653 --> 00:15:37,961 than in a city that never does? 271 00:15:37,961 --> 00:15:38,794 Come on! 272 00:15:38,794 --> 00:15:41,044 (cheering) 273 00:15:44,283 --> 00:15:45,955 If there's one place on Earth 274 00:15:45,955 --> 00:15:48,472 where we're willing to sacrifice a little bit of sleep 275 00:15:48,472 --> 00:15:50,522 in the hopes of gaining something better, 276 00:15:50,522 --> 00:15:52,272 it's here, Las Vegas. 277 00:15:53,338 --> 00:15:55,890 But this 24 hour town isn't the only place 278 00:15:55,890 --> 00:15:57,993 we're making this kind of trade off. 279 00:15:57,993 --> 00:16:00,623 Without realizing it, we might be losing something 280 00:16:00,623 --> 00:16:04,123 far more precious than just a few dollars. 281 00:16:05,968 --> 00:16:10,380 Doctor Scott Killgore is a professor of psychiatry. 282 00:16:10,380 --> 00:16:14,547 But he's also a lieutenant colonel in the US Army. 283 00:16:16,159 --> 00:16:18,393 Treating soldiers who fought on the front lines 284 00:16:18,393 --> 00:16:20,443 made Dr. Killgore realize 285 00:16:20,443 --> 00:16:24,610 that they provided a unique window on the world of sleep. 286 00:16:26,878 --> 00:16:28,251 We were doing sleep research 287 00:16:28,251 --> 00:16:30,852 and most people were just focusing in on reaction time 288 00:16:30,852 --> 00:16:33,137 and simple cognitive processes. 289 00:16:33,137 --> 00:16:36,443 But what about this other side of which choice to make? 290 00:16:36,443 --> 00:16:37,798 You know, do you drop the bomb now, 291 00:16:37,798 --> 00:16:40,385 do you pull the trigger, do you not pull the trigger? 292 00:16:40,385 --> 00:16:42,065 Because these are not cold decisions. 293 00:16:42,065 --> 00:16:45,482 You don't make them like a computer does. 294 00:16:47,434 --> 00:16:49,470 They're very emotionally charged situations 295 00:16:49,470 --> 00:16:51,987 and we need more information about how 296 00:16:51,987 --> 00:16:56,252 lack of sleep affects emotional functioning. 297 00:16:56,252 --> 00:16:57,661 At the heart of this quest 298 00:16:57,661 --> 00:16:59,974 lies a seeming contradiction. 299 00:16:59,974 --> 00:17:02,612 As it turns out, our emotions don't cause us 300 00:17:02,612 --> 00:17:04,771 to make bad decisions. 301 00:17:04,771 --> 00:17:09,330 Most of the time they actually help us make good ones. 302 00:17:09,330 --> 00:17:12,197 Every day I make thousands of choices, 303 00:17:12,197 --> 00:17:14,280 many of them intuitively. 304 00:17:15,198 --> 00:17:19,087 My intuition is guided by a special type of memory, 305 00:17:19,087 --> 00:17:20,504 an emotional one. 306 00:17:21,512 --> 00:17:23,199 When I experience something, 307 00:17:23,199 --> 00:17:27,490 my brain flags it as either positive or negative. 308 00:17:27,490 --> 00:17:29,610 When it's time to make a decision, 309 00:17:29,610 --> 00:17:32,360 these emotional memories help me. 310 00:17:34,418 --> 00:17:35,852 If you watch those old Star Trek episodes, 311 00:17:35,852 --> 00:17:38,766 you see that in situations Spock always had 312 00:17:38,766 --> 00:17:42,074 the logical decision making process. 313 00:17:42,074 --> 00:17:43,069 He was like a computer. 314 00:17:43,069 --> 00:17:45,692 So he didn't let emotions affect his decisions. 315 00:17:45,692 --> 00:17:49,422 Whereas, Kirk, he could tap into that gut feeling in the 316 00:17:49,422 --> 00:17:53,275 pit of his stomach and make the right command decision. 317 00:17:53,275 --> 00:17:56,136 To get inside the brain where these gut feelings, 318 00:17:56,136 --> 00:17:59,303 these emotional memories are created, 319 00:17:59,303 --> 00:18:02,851 Dr. Killgore came up with an ingenious experiment 320 00:18:02,851 --> 00:18:06,818 based on a specially designed gambling task. 321 00:18:06,818 --> 00:18:08,709 Now I'm gonna visit Dr. Killgore 322 00:18:08,709 --> 00:18:10,637 and put that task to the test 323 00:18:10,637 --> 00:18:12,846 and this time, what happens in Vegas 324 00:18:12,846 --> 00:18:17,013 won't be staying in Vegas, all in the name of science. 325 00:18:20,065 --> 00:18:22,504 So the basic idea here is that 326 00:18:22,504 --> 00:18:23,518 there are four decks of cards. 327 00:18:23,518 --> 00:18:24,351 Okay. 328 00:18:24,351 --> 00:18:26,844 And your job is to try to win as much money as possible. 329 00:18:26,844 --> 00:18:27,677 Ooh! 330 00:18:27,677 --> 00:18:31,344 And avoid losing any money in the process. 331 00:18:32,713 --> 00:18:34,453 (beeping) 332 00:18:34,453 --> 00:18:36,182 Hello, hundred dollars. 333 00:18:36,182 --> 00:18:38,246 But what no one's told me is that 334 00:18:38,246 --> 00:18:42,077 two of the decks will give me big wins 335 00:18:42,077 --> 00:18:43,994 but even bigger losses. 336 00:18:45,123 --> 00:18:46,028 Hmm. 337 00:18:46,028 --> 00:18:48,711 The other two decks deliver small wins 338 00:18:48,711 --> 00:18:50,294 but smaller losses. 339 00:18:52,813 --> 00:18:54,512 (buzzing) 340 00:18:54,512 --> 00:18:57,620 To come out ahead, I've got to rely on those gut feelings 341 00:18:57,620 --> 00:19:00,620 to help me make the right decisions. 342 00:19:02,109 --> 00:19:04,229 (beeping) 343 00:19:04,229 --> 00:19:05,819 All right, let's see. 344 00:19:05,819 --> 00:19:07,617 Turns out I did all right. 345 00:19:07,617 --> 00:19:10,123 I took home 1200 dollars. 346 00:19:10,123 --> 00:19:11,488 So, this is your baseline. 347 00:19:11,488 --> 00:19:13,319 So now what I want you to do is 348 00:19:13,319 --> 00:19:15,564 to go out and have some fun tonight. 349 00:19:15,564 --> 00:19:17,268 I can do that. 350 00:19:17,268 --> 00:19:19,935 It's time to get sleep deprived. 351 00:19:23,743 --> 00:19:26,464 (laughing) 352 00:19:26,464 --> 00:19:27,297 Yes! 353 00:19:30,850 --> 00:19:32,840 A little over a century ago, 354 00:19:32,840 --> 00:19:36,687 we slept, on average, nine hours a night. 355 00:19:36,687 --> 00:19:39,770 Today that's down to less than seven. 356 00:19:40,869 --> 00:19:43,608 So my night on the town is just a quick way 357 00:19:43,608 --> 00:19:47,338 to get me to where most of us already are, 358 00:19:47,338 --> 00:19:50,990 into a state of serious sleep deprivation. 359 00:19:50,990 --> 00:19:52,363 Jennifer. 360 00:19:52,363 --> 00:19:54,030 Are you still awake? 361 00:19:55,645 --> 00:19:56,645 No sleeping! 362 00:20:01,519 --> 00:20:02,618 Good morning, Doc. 363 00:20:02,618 --> 00:20:03,972 Hey, Jen, how are you doing? 364 00:20:03,972 --> 00:20:06,333 I gotta be honest, I'm really tired. 365 00:20:06,333 --> 00:20:09,412 I think I'm a nine out of a ten on the tired scale. 366 00:20:09,412 --> 00:20:10,986 So, did you get hitched? 367 00:20:10,986 --> 00:20:14,209 (laughs) No. 368 00:20:14,209 --> 00:20:16,626 After 24 hours without sleep, 369 00:20:17,505 --> 00:20:20,838 it's time to do the gambling task again. 370 00:20:23,226 --> 00:20:24,309 Hello, cards. 371 00:20:25,238 --> 00:20:26,488 My old friends. 372 00:20:27,518 --> 00:20:30,174 This time I keep losing track of the decks 373 00:20:30,174 --> 00:20:34,341 and no matter how much I try, I can't seem to stay focused. 374 00:20:38,825 --> 00:20:41,464 Yesterday I won 1200 bucks, 375 00:20:41,464 --> 00:20:42,881 today I lose 800. 376 00:20:46,221 --> 00:20:47,888 Whoa, I sucked. 377 00:20:47,888 --> 00:20:49,681 The reason can be found here, 378 00:20:49,681 --> 00:20:53,226 in my ventromedial prefrontal cortex. 379 00:20:53,226 --> 00:20:56,904 This is where those emotional memories are incorporated 380 00:20:56,904 --> 00:21:00,407 with my reasoning to guide my decision making. 381 00:21:00,407 --> 00:21:03,593 Normally, this area is very active. 382 00:21:03,593 --> 00:21:06,699 But after 24 hours without sleep, 383 00:21:06,699 --> 00:21:10,866 this critical part of my brain has simply shut down. 384 00:21:11,712 --> 00:21:12,976 It's not active anymore. 385 00:21:12,976 --> 00:21:13,809 Yeah. 386 00:21:13,809 --> 00:21:17,593 So it's not able to turn on and integrate your emotions 387 00:21:17,593 --> 00:21:19,556 to guide your cognitions and your thoughts 388 00:21:19,556 --> 00:21:20,505 and your decisions. 389 00:21:20,505 --> 00:21:22,471 So your judgements start to get impaired. 390 00:21:22,471 --> 00:21:23,550 You don't know the right answer, 391 00:21:23,550 --> 00:21:26,261 you can't rely on your gut to tell you, 392 00:21:26,261 --> 00:21:27,335 "That's the way I should go." 393 00:21:27,335 --> 00:21:28,168 Yeah. 394 00:21:28,168 --> 00:21:31,501 It was impossible to tune in onto those, 395 00:21:32,611 --> 00:21:33,898 the good decks and the bad decks. 396 00:21:33,898 --> 00:21:35,753 Right, the ability to integrate the emotions 397 00:21:35,753 --> 00:21:38,185 with decision making becomes affected. 398 00:21:38,185 --> 00:21:40,375 So you just flounder. 399 00:21:40,375 --> 00:21:43,668 What's fascinating is that Dr. Killgore found this 400 00:21:43,668 --> 00:21:47,583 same impaired judgment in people with stroke damage 401 00:21:47,583 --> 00:21:51,221 in this exact same part of the brain. 402 00:21:51,221 --> 00:21:54,005 So, in essence, sleep depravation is almost 403 00:21:54,005 --> 00:21:56,317 a temporary brain injury. 404 00:21:56,317 --> 00:21:58,903 Yeah, it's basically very much like you're 405 00:21:58,903 --> 00:22:00,937 brain damaged, but getting a good night's sleep 406 00:22:00,937 --> 00:22:02,636 can actually reverse the process 407 00:22:02,636 --> 00:22:04,164 and get you back to your baseline. 408 00:22:04,164 --> 00:22:06,770 Well, that's good because you know what I could 409 00:22:06,770 --> 00:22:09,420 use right now is my baseline level. 410 00:22:09,420 --> 00:22:12,587 I would really like to get back there. 411 00:22:14,794 --> 00:22:17,989 By delving deep into our brain, Dr. Killgore 412 00:22:17,989 --> 00:22:20,460 has discovered a direct relationship between 413 00:22:20,460 --> 00:22:23,286 sleep and the emotional switching system 414 00:22:23,286 --> 00:22:26,294 that guides our decision making. 415 00:22:26,294 --> 00:22:27,630 We don't understand everything yet, 416 00:22:27,630 --> 00:22:29,496 but so much of the work that we've been doing 417 00:22:29,496 --> 00:22:30,983 shows that even cutting your sleep down 418 00:22:30,983 --> 00:22:32,840 by a couple of hours 419 00:22:32,840 --> 00:22:34,591 alters the connectivity in the brain 420 00:22:34,591 --> 00:22:37,865 and that in turn affects your emotional intelligence 421 00:22:37,865 --> 00:22:42,032 and your decision making and all these areas in life. 422 00:22:43,816 --> 00:22:46,483 Lights off in three, two, one. 423 00:22:50,274 --> 00:22:51,761 For two and a half years, 424 00:22:51,761 --> 00:22:55,542 volunteers have lived here at the University of Colorado 425 00:22:55,542 --> 00:22:57,792 inside a kind of biosphere. 426 00:22:58,913 --> 00:23:00,720 For two weeks at a time, 427 00:23:00,720 --> 00:23:04,098 they sleep, eat, and work in this lab, 428 00:23:04,098 --> 00:23:07,176 isolated from the outside world. 429 00:23:07,176 --> 00:23:10,177 Everything they do is carefully monitored. 430 00:23:10,177 --> 00:23:12,863 They can't take a nap or eat a calorie 431 00:23:12,863 --> 00:23:15,030 without it being measured. 432 00:23:17,233 --> 00:23:18,280 Hey Chris, let's go in, let's get started. 433 00:23:18,280 --> 00:23:20,374 All right, sounds good. 434 00:23:20,374 --> 00:23:22,336 This experiment is the brainchild of 435 00:23:22,336 --> 00:23:25,169 neuroscientist, Doctor Ken Wright. 436 00:23:26,800 --> 00:23:30,560 If sleep deprivation can cause temporary brain damage, 437 00:23:30,560 --> 00:23:33,485 Dr. Wright wondered if it could also disrupt 438 00:23:33,485 --> 00:23:36,602 another system regulated by our brain, 439 00:23:36,602 --> 00:23:39,769 the one that controls how much we eat. 440 00:23:41,006 --> 00:23:43,364 1.5 billion adults worldwide, 441 00:23:43,364 --> 00:23:45,580 about 150 million school age children 442 00:23:45,580 --> 00:23:48,733 and 43 million preschool children 443 00:23:48,733 --> 00:23:50,624 are overweight or obese. 444 00:23:50,624 --> 00:23:53,747 And over half of our adult population right now 445 00:23:53,747 --> 00:23:58,070 is not getting that minimum of seven hours a night. 446 00:23:58,070 --> 00:23:59,794 (on intercom) Hey gang, just checking in with you. 447 00:23:59,794 --> 00:24:01,843 How's it going tonight so far? 448 00:24:01,843 --> 00:24:02,820 It's going good. 449 00:24:02,820 --> 00:24:05,577 Dr. Wright created this isolation chamber 450 00:24:05,577 --> 00:24:09,838 to take volunteers deep into sleep deprivation 451 00:24:09,838 --> 00:24:14,005 to see if that would have an impact on their weight. 452 00:24:16,549 --> 00:24:19,480 For a week now, this group has been allowed to sleep 453 00:24:19,480 --> 00:24:21,574 nine hours a night. 454 00:24:21,574 --> 00:24:22,769 Okay, big boy, time to wake up. 455 00:24:22,769 --> 00:24:26,485 And eat as much food as they want. 456 00:24:26,485 --> 00:24:29,863 But now it's time for a radical change. 457 00:24:29,863 --> 00:24:31,344 Yeah, what do you think? 458 00:24:31,344 --> 00:24:34,273 The volunteers are about to have their sleep cut 459 00:24:34,273 --> 00:24:36,842 by nearly 50 percent. 460 00:24:36,842 --> 00:24:40,461 For the next week, they'll get just five hours a night. 461 00:24:40,461 --> 00:24:41,397 I'll give you a countdown. 462 00:24:41,397 --> 00:24:45,564 I'll dim the lights and then give you a countdown. 463 00:24:54,018 --> 00:24:55,185 Morning, Jake. 464 00:24:56,348 --> 00:24:57,598 Good morning. 465 00:24:59,942 --> 00:25:00,775 Hey, Chris. 466 00:25:00,775 --> 00:25:01,942 How's the subject going today? 467 00:25:01,942 --> 00:25:03,810 As the 50 percent cut in sleep 468 00:25:03,810 --> 00:25:07,453 begins to take a toll, Dr. Wright notices a change 469 00:25:07,453 --> 00:25:09,891 in the amount the volunteers are eating. 470 00:25:09,891 --> 00:25:11,475 So, as we've been following people's food intake 471 00:25:11,475 --> 00:25:13,455 across these last four days, 472 00:25:13,455 --> 00:25:15,101 we're seeing something remarkable. 473 00:25:15,101 --> 00:25:18,014 Their food intake is going up, so they're eating more. 474 00:25:18,014 --> 00:25:20,230 And not just at mealtimes. 475 00:25:20,230 --> 00:25:24,547 The volunteers are also consuming more snacks. 476 00:25:24,547 --> 00:25:25,464 A lot more. 477 00:25:28,838 --> 00:25:30,409 What we're starting to see is that 478 00:25:30,409 --> 00:25:31,609 they're eating more after dinner 479 00:25:31,609 --> 00:25:34,029 than they do at any meal across the entire day. 480 00:25:34,029 --> 00:25:36,469 So it's as if they're eating four meals a day 481 00:25:36,469 --> 00:25:38,831 rather than just three. 482 00:25:38,831 --> 00:25:41,702 But what's most fascinating for Dr. Wright 483 00:25:41,702 --> 00:25:44,935 is the impact on the two hormones that regulate 484 00:25:44,935 --> 00:25:46,268 how much we eat. 485 00:25:47,132 --> 00:25:49,465 (crunching) 486 00:25:52,219 --> 00:25:56,634 Ghrelin and Leptin are called the hunger hormones. 487 00:25:56,634 --> 00:26:00,717 Ghrelins signals the brain when it's time to eat. 488 00:26:02,597 --> 00:26:05,280 Leptin tells the brain when the body has enough 489 00:26:05,280 --> 00:26:08,863 stored energy and it's time to stop eating. 490 00:26:12,738 --> 00:26:15,618 The lack of sleep seems to be causing a meltdown 491 00:26:15,618 --> 00:26:19,785 in this critical part of our weight regulation system. 492 00:26:26,636 --> 00:26:28,810 As the volunteers eat more, 493 00:26:28,810 --> 00:26:31,452 both Grehlin and Leptin are telling the brain 494 00:26:31,452 --> 00:26:34,193 it's time to stop eating. 495 00:26:34,193 --> 00:26:37,953 But these messages aren't getting through. 496 00:26:37,953 --> 00:26:41,183 And the amount of weight gained by the volunteers 497 00:26:41,183 --> 00:26:42,183 is stunning. 498 00:26:44,235 --> 00:26:46,700 For these participants after just five days 499 00:26:46,700 --> 00:26:47,807 of getting too little sleep, 500 00:26:47,807 --> 00:26:49,890 they gained .8 kilograms. 501 00:26:51,553 --> 00:26:53,922 It used to be thought that sleep was just for us 502 00:26:53,922 --> 00:26:56,123 to feel alert during the day 503 00:26:56,123 --> 00:26:58,839 and for us to think clearly and perform cognitively 504 00:26:58,839 --> 00:26:59,688 at our best, 505 00:26:59,688 --> 00:27:02,581 but unfortunately, when people are not getting enough sleep, 506 00:27:02,581 --> 00:27:04,368 they eat more. 507 00:27:04,368 --> 00:27:07,458 And sleep loss is known now to contribute to that risk 508 00:27:07,458 --> 00:27:09,005 of gaining weight. 509 00:27:09,005 --> 00:27:11,023 People recognize that sleep is something 510 00:27:11,023 --> 00:27:12,919 that they can easily give up. 511 00:27:12,919 --> 00:27:15,403 But when they make that choice, 512 00:27:15,403 --> 00:27:16,757 they're not always thinking about 513 00:27:16,757 --> 00:27:19,425 the long term consequences of that. 514 00:27:19,425 --> 00:27:20,946 While they may get sleepy, 515 00:27:20,946 --> 00:27:23,052 the effects of developing heart disease, 516 00:27:23,052 --> 00:27:24,687 the effects of developing obesity, 517 00:27:24,687 --> 00:27:26,687 those are down the road. 518 00:27:28,372 --> 00:27:30,364 Sleep regulates our weight 519 00:27:30,364 --> 00:27:32,158 and guides our decisions. 520 00:27:32,158 --> 00:27:35,204 But does it have an impact on another key function 521 00:27:35,204 --> 00:27:37,412 controlled by our brain? 522 00:27:37,412 --> 00:27:38,844 Dreaming. 523 00:27:38,844 --> 00:27:41,179 Scientists are now trying to discover 524 00:27:41,179 --> 00:27:43,965 if our dream world plays an important role 525 00:27:43,965 --> 00:27:45,632 in our waking lives. 526 00:27:55,938 --> 00:27:59,431 Dr. Antonio Zadra can't remember a time in his life 527 00:27:59,431 --> 00:28:02,348 when he wasn't intrigued by dreams. 528 00:28:04,079 --> 00:28:06,631 Dreams have always fascinated humankind 529 00:28:06,631 --> 00:28:08,567 and so people have always been curious about, 530 00:28:08,567 --> 00:28:11,832 since the dawn of history, about where dreams come from, 531 00:28:11,832 --> 00:28:15,665 how are they formed, do they have any meaning? 532 00:28:16,812 --> 00:28:21,487 We spend 52,000 hours of our lives dreaming. 533 00:28:21,487 --> 00:28:22,820 Six solid years. 534 00:28:23,836 --> 00:28:27,026 Dr. Zadra is convinced that within this vast ocean 535 00:28:27,026 --> 00:28:30,443 of dreaming lies the key to its function. 536 00:28:37,040 --> 00:28:39,398 To unlock the secrets of our dreams, 537 00:28:39,398 --> 00:28:42,768 Dr. Zadra first had to find a way to enter 538 00:28:42,768 --> 00:28:44,601 this mysterious world. 539 00:28:46,269 --> 00:28:50,436 People like artist James Simon turned out to be the key. 540 00:28:52,301 --> 00:28:54,535 Along with nearly 100 others, 541 00:28:54,535 --> 00:28:57,448 James is part of a unique group. 542 00:28:57,448 --> 00:29:00,764 He is one of Dr. Zadra's dreamers. 543 00:29:00,764 --> 00:29:02,710 But I'm aware in the dream that this raven 544 00:29:02,710 --> 00:29:06,542 has a propensity to lunge for a person's eyes. 545 00:29:06,542 --> 00:29:09,557 As an instinct, as a reflex. 546 00:29:09,557 --> 00:29:11,906 Dr. Zadra has collected and assessed 547 00:29:11,906 --> 00:29:16,073 an astonishing 10,000 dreams from people like James Simon. 548 00:29:18,156 --> 00:29:21,578 He discovered that women have more nightmares than men 549 00:29:21,578 --> 00:29:24,535 and that we dream about different things, 550 00:29:24,535 --> 00:29:29,076 women about relationships and men about calamities. 551 00:29:29,076 --> 00:29:31,758 He's also uncovered that dreams provide a window 552 00:29:31,758 --> 00:29:35,402 into our psychological well being. 553 00:29:35,402 --> 00:29:37,001 The more negative emotions you have in your dreams, 554 00:29:37,001 --> 00:29:40,513 the more negative interactions, aggressive interactions 555 00:29:40,513 --> 00:29:42,996 you have with other characters in your dreams, 556 00:29:42,996 --> 00:29:45,274 the less happy you tend to be, 557 00:29:45,274 --> 00:29:48,163 or the more anxious or depressed you tend to be. 558 00:29:48,163 --> 00:29:51,433 Taken together, Dr. Zadra's discoveries reveal 559 00:29:51,433 --> 00:29:55,289 that dreams are not the random and chaotic occurrences 560 00:29:55,289 --> 00:29:57,456 most of us think they are. 561 00:29:58,763 --> 00:30:00,480 When you look at people's dreams, 562 00:30:00,480 --> 00:30:02,856 you see that there is more order in them 563 00:30:02,856 --> 00:30:04,895 in the sense that you see a continuation 564 00:30:04,895 --> 00:30:07,645 between what's going on during wakefulness 565 00:30:07,645 --> 00:30:10,312 and the content in their dreams. 566 00:30:13,406 --> 00:30:15,719 Both Dr. Zadra and sleep scientist 567 00:30:15,719 --> 00:30:19,116 Dr. Robert Stickgold believe the connection between 568 00:30:19,116 --> 00:30:21,842 our waking lives and our dream world 569 00:30:21,842 --> 00:30:25,961 is a critical clue to the function of dreams. 570 00:30:25,961 --> 00:30:29,684 It's when we sleep and in part when we dream 571 00:30:29,684 --> 00:30:33,851 that we normally figure out what the events of our day mean. 572 00:30:36,459 --> 00:30:38,981 Dr. Stickgold believes this because 573 00:30:38,981 --> 00:30:42,346 of an extraordinary conversation that takes place 574 00:30:42,346 --> 00:30:44,513 inside our sleeping brain. 575 00:30:46,133 --> 00:30:49,696 When we first go to sleep, the memories we've accumulated 576 00:30:49,696 --> 00:30:52,863 during the day flow from the hippocampus, 577 00:30:52,863 --> 00:30:56,771 where they've been stored and assessed, to the neocortex, 578 00:30:56,771 --> 00:31:00,142 where they're associated with other memories. 579 00:31:00,142 --> 00:31:04,225 The neocortex kicks into high gear when we dream. 580 00:31:05,287 --> 00:31:07,222 Then in that first REM cycle, 581 00:31:07,222 --> 00:31:12,142 it's as if the neocortex says back to the hippocampus, 582 00:31:12,142 --> 00:31:15,395 "Oh, that's like what happened last month." 583 00:31:15,395 --> 00:31:17,763 It's as if now the front of the brain 584 00:31:17,763 --> 00:31:21,327 is telling the hippocampus, "Okay, you know what? 585 00:31:21,327 --> 00:31:23,677 Those details aren't important." 586 00:31:23,677 --> 00:31:26,097 Or, "Those details are important." 587 00:31:26,097 --> 00:31:29,360 And telling the hippocampus what to do with that information 588 00:31:29,360 --> 00:31:33,841 and also working out itself, in the neocortex, 589 00:31:33,841 --> 00:31:36,424 seeing how things fit together. 590 00:31:39,685 --> 00:31:42,204 To confirm that dreaming really does help us 591 00:31:42,204 --> 00:31:45,058 associate memories in order to give them meaning, 592 00:31:45,058 --> 00:31:48,975 Dr. Stickgold created a series of unique tests. 593 00:31:51,838 --> 00:31:55,382 In one expermient, Dr. Stickgold trained a group of people 594 00:31:55,382 --> 00:31:56,378 to go through a maze. 595 00:31:56,378 --> 00:31:59,961 Afterwards, half had a nap and half didn't. 596 00:32:01,066 --> 00:32:04,474 Later that day, people came back and ran the maze again. 597 00:32:04,474 --> 00:32:07,705 Those that had napped found the exit more quickly. 598 00:32:07,705 --> 00:32:10,440 But what got Dr. Stickgold really excited 599 00:32:10,440 --> 00:32:14,607 were those people who both napped and dreamt about the maze. 600 00:32:16,779 --> 00:32:19,862 They found the exit ten times faster. 601 00:32:21,627 --> 00:32:22,655 I think what we're seeing now 602 00:32:22,655 --> 00:32:25,905 is that dreams in fact are a reflection 603 00:32:26,875 --> 00:32:29,704 of the kind of processing that the brain does 604 00:32:29,704 --> 00:32:30,954 while we sleep. 605 00:32:33,223 --> 00:32:37,130 Just us being conscious while we're asleep 606 00:32:37,130 --> 00:32:40,949 and conscious of things that our brain is 607 00:32:40,949 --> 00:32:42,949 constructing as stories. 608 00:32:44,236 --> 00:32:46,381 And so we're really watching over the shoulder 609 00:32:46,381 --> 00:32:47,798 of a film editor. 610 00:32:48,835 --> 00:32:51,784 But if you just watch the screen of the editor, 611 00:32:51,784 --> 00:32:54,246 it looks crazy, like a dream. 612 00:32:54,246 --> 00:32:56,710 Things are juxtaposed from different places, 613 00:32:56,710 --> 00:32:59,498 you don't know why they're being juxtaposed. 614 00:32:59,498 --> 00:33:01,835 Things are being replayed. 615 00:33:01,835 --> 00:33:04,734 It's as if the brain, while we're dreaming, 616 00:33:04,734 --> 00:33:08,151 is trying to see how things fit together. 617 00:33:16,515 --> 00:33:18,283 According to Dr. Stickgold, 618 00:33:18,283 --> 00:33:21,284 this is my sleeping brain giving meaning 619 00:33:21,284 --> 00:33:23,844 to the events of my life. 620 00:33:23,844 --> 00:33:27,970 Dr. Zadra believes if patterns can be found in this chaos, 621 00:33:27,970 --> 00:33:30,652 they have the power to reveal something 622 00:33:30,652 --> 00:33:33,485 about my psychological well being. 623 00:33:34,771 --> 00:33:36,655 Before I arrived at his lab, 624 00:33:36,655 --> 00:33:39,541 he asked me to keep a dream diary. 625 00:33:39,541 --> 00:33:43,708 So for the last six weeks, I've been writing down my dreams. 626 00:33:45,218 --> 00:33:47,752 I had a chance to read over your dreams 627 00:33:47,752 --> 00:33:49,617 and try to quantify their contents, 628 00:33:49,617 --> 00:33:52,373 in terms of the characters we see, the settings, 629 00:33:52,373 --> 00:33:54,635 the social interactions. 630 00:33:54,635 --> 00:33:56,922 Dr. Zadra knows very little about me, 631 00:33:56,922 --> 00:33:59,087 only that I'm a TV host. 632 00:33:59,087 --> 00:34:01,928 But right away he uncovers my anxieties about 633 00:34:01,928 --> 00:34:06,180 solving problems in a dream about a leaking pipe. 634 00:34:06,180 --> 00:34:08,019 So there's all the water, which is a misfortune, 635 00:34:08,019 --> 00:34:10,281 not your fault, but you still-- 636 00:34:10,281 --> 00:34:11,531 I have to fix it. Unplug it. 637 00:34:11,531 --> 00:34:13,448 You still get the towels, you still mop it up. 638 00:34:13,448 --> 00:34:14,281 Yeah. 639 00:34:14,281 --> 00:34:17,268 And so, um, you're still trying somehow 640 00:34:17,268 --> 00:34:21,010 to minimize the damage or to try to 641 00:34:21,010 --> 00:34:23,647 bring it under control to whatever extent you can. 642 00:34:23,647 --> 00:34:26,361 Dr. Zadra also totally nails 643 00:34:26,361 --> 00:34:28,497 that I worry about outward appearances 644 00:34:28,497 --> 00:34:31,118 and about the value of my work. 645 00:34:31,118 --> 00:34:33,398 But there's one revelation from my dreams 646 00:34:33,398 --> 00:34:36,916 that catches me completely off guard. 647 00:34:36,916 --> 00:34:38,442 In over half of your dreams, 648 00:34:38,442 --> 00:34:40,043 there are references to animals. 649 00:34:40,043 --> 00:34:41,546 So the fact that there are many animals 650 00:34:41,546 --> 00:34:43,685 and the way you interact with them, 651 00:34:43,685 --> 00:34:45,868 I would say that you're concerned about 652 00:34:45,868 --> 00:34:46,889 animals' well beings. 653 00:34:46,889 --> 00:34:49,627 Not just your dog or your cat, if you happen to have one, 654 00:34:49,627 --> 00:34:52,214 but that the well being of animals is something 655 00:34:52,214 --> 00:34:53,888 that is dear to you, generally. 656 00:34:53,888 --> 00:34:56,033 This is crazy, you're making me all misty 657 00:34:56,033 --> 00:34:59,034 and teary-eyed, because this is remarkable. 658 00:34:59,034 --> 00:35:01,025 Absolutely remarkable. 659 00:35:01,025 --> 00:35:05,354 I do, I have a cat, I have a dog, I love them to pieces, 660 00:35:05,354 --> 00:35:07,330 I love all animals. 661 00:35:07,330 --> 00:35:08,962 This is remarkable. 662 00:35:08,962 --> 00:35:11,379 (laughs) Wow. 663 00:35:12,711 --> 00:35:16,478 I think this entire exercise for Jen 664 00:35:16,478 --> 00:35:18,317 probably made her much more appreciative 665 00:35:18,317 --> 00:35:19,892 of the power of dreams 666 00:35:19,892 --> 00:35:23,785 and again of the order that we can find in dreams 667 00:35:23,785 --> 00:35:26,283 and the psychological meanings we can find in dreams. 668 00:35:26,283 --> 00:35:29,189 So there's a relationship over time 669 00:35:29,189 --> 00:35:31,579 about how well people are functioning 670 00:35:31,579 --> 00:35:32,823 and how well they feel 671 00:35:32,823 --> 00:35:36,990 and the content and patterns in their dreams as well. 672 00:35:38,006 --> 00:35:39,712 If sleep allows us to enter 673 00:35:39,712 --> 00:35:43,915 the mysterious world of dreams, could it also be involved 674 00:35:43,915 --> 00:35:47,915 in one of the brain's greatest unsolved puzzles? 675 00:35:49,685 --> 00:35:53,320 Every night, virtually every species on the planet 676 00:35:53,320 --> 00:35:54,487 goes to sleep. 677 00:35:55,590 --> 00:35:58,588 For the first time, we're beginning to understand 678 00:35:58,588 --> 00:36:01,114 how this nightly ritual regulates 679 00:36:01,114 --> 00:36:04,447 almost every aspect of our waking lives. 680 00:36:05,737 --> 00:36:09,425 But there's one discovery that's eluded researchers. 681 00:36:09,425 --> 00:36:13,508 Uncovering the core biological function of sleep. 682 00:36:15,832 --> 00:36:18,482 For neuroscientist Doctor Jeff Iliff 683 00:36:18,482 --> 00:36:20,963 and a team from Rochester University, 684 00:36:20,963 --> 00:36:23,900 their quest begins with a baffling clue 685 00:36:23,900 --> 00:36:26,531 about a protein that's the key culprit 686 00:36:26,531 --> 00:36:29,269 in Alzheimer's disease. 687 00:36:29,269 --> 00:36:31,406 So there's a protein called amyloid beta, 688 00:36:31,406 --> 00:36:33,266 which is made in the brain all the time. 689 00:36:33,266 --> 00:36:35,507 Now, when you're awake, amyloid beta levels 690 00:36:35,507 --> 00:36:36,842 in the brain go up 691 00:36:36,842 --> 00:36:38,317 and when you're asleep during the night, 692 00:36:38,317 --> 00:36:41,043 amyloid beta levels in the brain go down. 693 00:36:41,043 --> 00:36:43,155 The question is why. 694 00:36:43,155 --> 00:36:45,507 To find out, Dr. Iliff hopes to do 695 00:36:45,507 --> 00:36:49,964 what few sleep scientists have ever done before. 696 00:36:49,964 --> 00:36:53,131 Look directly into the sleeping brain. 697 00:36:54,798 --> 00:36:57,212 We have a very powerful and specialized microscope 698 00:36:57,212 --> 00:36:59,606 that can actually shine through the skull 699 00:36:59,606 --> 00:37:03,773 into the living brain while it's doing all of its processes. 700 00:37:05,174 --> 00:37:09,341 This is the world of the sleeping brain. 701 00:37:13,472 --> 00:37:17,925 What Dr. Iliff sees is a complex network of blood vessels 702 00:37:17,925 --> 00:37:20,651 that dive deep into the brain's center, 703 00:37:20,651 --> 00:37:24,783 supplying nutrients and oxygen to its cells. 704 00:37:24,783 --> 00:37:29,320 But there's something else, something completely unexpected. 705 00:37:29,320 --> 00:37:32,403 At night, the brain begins to change. 706 00:37:34,065 --> 00:37:36,562 Something's happening within the tissue itself. 707 00:37:36,562 --> 00:37:39,397 The brain's cells, the support cells in the brain, 708 00:37:39,397 --> 00:37:41,314 are actually shrinking. 709 00:37:44,124 --> 00:37:46,117 Dr. Iliff believes the team has 710 00:37:46,117 --> 00:37:49,079 stumbled upon a clue that may be connected 711 00:37:49,079 --> 00:37:52,713 to one of the brain's most puzzling mysteries. 712 00:37:52,713 --> 00:37:54,463 How it cleans itself. 713 00:37:58,622 --> 00:38:00,331 Like the tributaries of a river, 714 00:38:00,331 --> 00:38:03,743 our body relies on the circulatory system 715 00:38:03,743 --> 00:38:07,493 to bring nutrients to its trillions of cells. 716 00:38:09,314 --> 00:38:12,231 But these cells also produce waste. 717 00:38:15,784 --> 00:38:19,117 In a river, sediment settles to the bottom, 718 00:38:19,117 --> 00:38:21,141 but in our bodies, we have lymph vessels 719 00:38:21,141 --> 00:38:24,338 to collect the waste and carry it through our bloodstream 720 00:38:24,338 --> 00:38:28,338 to places like the liver, where it's eliminated. 721 00:38:30,937 --> 00:38:32,105 But there's one part of the body 722 00:38:32,105 --> 00:38:36,726 the lymph vessels don't go to and that's the brain. 723 00:38:36,726 --> 00:38:39,643 So how does the brain clean itself? 724 00:38:45,780 --> 00:38:48,469 Dr. Iliff believes the answer is connected 725 00:38:48,469 --> 00:38:51,199 to the mysterious changes he observed 726 00:38:51,199 --> 00:38:54,949 taking place inside the brain while we sleep. 727 00:38:56,674 --> 00:38:59,738 During the day, the brain is protected by a sac 728 00:38:59,738 --> 00:39:02,738 filled with fluid that surrounds it. 729 00:39:04,471 --> 00:39:09,375 But as Dr. Iliff discovers, at night this sac empties 730 00:39:09,375 --> 00:39:12,708 and the fluid filters through the brain. 731 00:39:14,113 --> 00:39:15,511 What was happening was that 732 00:39:15,511 --> 00:39:18,960 the fluid was piggybacking, using the structure 733 00:39:18,960 --> 00:39:23,809 of the blood vessels to get access to the entire brain. 734 00:39:23,809 --> 00:39:26,536 But it's what the fluid does that provides 735 00:39:26,536 --> 00:39:30,703 Dr. Iliff and his team with an extraordinary breakthrough. 736 00:39:32,741 --> 00:39:34,824 The fluid that's on the outside of the brain, 737 00:39:34,824 --> 00:39:36,248 as it flows along those blood vessels 738 00:39:36,248 --> 00:39:37,825 and through the brain tissue, 739 00:39:37,825 --> 00:39:40,211 it's doing the most amazing thing. 740 00:39:40,211 --> 00:39:42,746 It's clearing away, washing away, 741 00:39:42,746 --> 00:39:47,728 the waste particles in the spaces between the brain's cells. 742 00:39:47,728 --> 00:39:48,609 Wow. 743 00:39:48,609 --> 00:39:51,268 We can't multitask enough during the day, 744 00:39:51,268 --> 00:39:52,928 we have to set something aside. 745 00:39:52,928 --> 00:39:54,352 Housekeeping happens at night. 746 00:39:54,352 --> 00:39:56,809 Yeah, it's a very clever way to do, really, 747 00:39:56,809 --> 00:39:58,545 two things with the same structure, 748 00:39:58,545 --> 00:40:01,553 both provide nutrients and clear away the waste. 749 00:40:01,553 --> 00:40:02,537 But it's unique. 750 00:40:02,537 --> 00:40:06,138 No other part of the body uses a plan like this 751 00:40:06,138 --> 00:40:07,695 to do these two things. 752 00:40:07,695 --> 00:40:09,203 It's a brains cleaning system. 753 00:40:09,203 --> 00:40:10,036 It is. 754 00:40:10,036 --> 00:40:14,177 It's sort of like a dishwasher for the brain. 755 00:40:14,177 --> 00:40:17,580 But Dr. Iliff and his team aren't done yet. 756 00:40:17,580 --> 00:40:20,396 There's still the question of amyloid beta, 757 00:40:20,396 --> 00:40:24,081 the protein that started them on this journey. 758 00:40:24,081 --> 00:40:26,531 Amyloid beta is one of the waste products 759 00:40:26,531 --> 00:40:28,666 produced by the brain. 760 00:40:28,666 --> 00:40:30,976 It's also the same protein that builds up 761 00:40:30,976 --> 00:40:35,143 in the brains of people suffering from Alzheimer's disease. 762 00:40:36,167 --> 00:40:39,215 When Dr. Iliff started this research, 763 00:40:39,215 --> 00:40:42,393 he saw levels of amyloid beta rise in the brain 764 00:40:42,393 --> 00:40:45,143 during the day and drop at night. 765 00:40:48,327 --> 00:40:49,744 Now he knows why. 766 00:40:51,277 --> 00:40:54,591 The brain is washing away this dangerous protein 767 00:40:54,591 --> 00:40:55,841 while we sleep. 768 00:40:59,968 --> 00:41:01,976 So, circling back to the beginning, 769 00:41:01,976 --> 00:41:05,541 what does this tell you about Alzheimer's? 770 00:41:05,541 --> 00:41:08,976 Well, it tells us that this process 771 00:41:08,976 --> 00:41:11,726 may be part of what's going wrong 772 00:41:12,690 --> 00:41:14,422 in patients with Alzheimer's disease. 773 00:41:14,422 --> 00:41:17,038 Worsening sleep quality and sleep duration 774 00:41:17,038 --> 00:41:20,750 are both associated with worsening amyloid plaque burden, 775 00:41:20,750 --> 00:41:23,126 so more amyloid beta building up in the brain. 776 00:41:23,126 --> 00:41:25,176 And so the failure of the brain to sort of 777 00:41:25,176 --> 00:41:28,036 keep its house clean and clear away these things 778 00:41:28,036 --> 00:41:30,519 that it needs to be clearing away during sleep 779 00:41:30,519 --> 00:41:31,848 may actually be setting the stage 780 00:41:31,848 --> 00:41:36,015 for the development of diseases like Alzheimer's disease. 781 00:41:39,105 --> 00:41:41,653 For the first time, we're realizing 782 00:41:41,653 --> 00:41:44,494 that our sleeping brain is the foundation 783 00:41:44,494 --> 00:41:46,744 of almost everything we do. 784 00:41:48,549 --> 00:41:50,795 I think sleep is fundamental to life. 785 00:41:50,795 --> 00:41:53,304 We're recognizing the importance of sleep 786 00:41:53,304 --> 00:41:55,062 for our whole body. 787 00:41:55,062 --> 00:41:57,145 Sleep effects everything. 788 00:41:58,362 --> 00:42:01,071 I think that the occurrence of what happens during sleep 789 00:42:01,071 --> 00:42:04,953 permits what happens in the waking brain 790 00:42:04,953 --> 00:42:08,324 and that you could not have all of the magic 791 00:42:08,324 --> 00:42:10,656 of the waking brain without all of the mystery 792 00:42:10,656 --> 00:42:12,489 of the sleeping brain. 793 00:42:14,149 --> 00:42:18,316 We create the meaning of our lives while we sleep. 794 00:42:19,493 --> 00:42:21,326 And that's phenomenal. 795 00:42:33,407 --> 00:42:36,324 (electronic music) 796 00:43:26,747 --> 00:43:28,061 (thwack) 797 00:43:28,061 --> 00:43:30,311 (applause)