2023-09-19 by Khushi Goel

[Transcript] IndiaAsksWhy | Why Do We Dream?

[00:10]

Both- “Hi Everyone”

Utsuka- I am Utsuka

Jigyasa- I am Jigyasa and you are listening to IndiaAsksWhy season 3 supported by IndiaBioScience extension grant.

[00:26]

J: At India Asks Why? We love chasing curious science questions.

U: This season, listeners from across schools are joining us on our curiosity chasing endeavor.

[00:44]

U: Bizarre, funny and weird, life is full of such dreams. We remember some but forget most of them. Ever wondered why we dream? This was a question posed by one of our listeners from class 9, Delhi Public School, Secunderabad. Join Utsuka and Jigyasa, as they chase this question with three other curious minds: Navika, Satakshi, and Fareeha. We also have Dr Nitin Chouhan, a sleep scientist from TIFR Mumbai chatting with the curious team about what might be happening in our brains when we dream. In the “life of a scientist" segment, the students asked Dr Chouhan about how he studies sleep in fruit flies, what his day in the lab looks like and how he became a scientist.

[01:45]

Navika: I had such a weird dream the other night. I was sitting in my classroom wearing my night suit.

[01:52]

Fariha: My dream, I wanted to get up from the bed and walk. But I couldn't. So weird.

[02:00]

Satakshi: Dreams can sometimes really puzzle us. I wonder why we have dreams?

[02:04]

U: Such an interesting question. Let's find out.

[02:12]

J: There is so much research on dreams. Neuroscientists and psychologists have been curious about the purpose of dreams through the years.

[02:23]

Nithin Chouhan: According to some ideas, you are dreaming all the time. It's just that when you sleep, all the other senses are going down, so you can actually see what you're dreaming. But the rest of the day, because of all the other sensory information, you might not be able to sense it.

[02:40]

J: A long drawn hypothesis in the field has been that dreams help in housekeeping of our brains.

[02:47]

Satakshi: Housekeeping of our brains? Is our brain like a hotel where you need regular cleaning?

[02:52]

J: Yes, indeed. Our brain does so many things throughout the day and so much information goes in and out of the brain. We see and do so many things.

[03:05]

Fariha: But we only remember some important things from a particular day and mostly forget irrelevant information after a few days.

[03:13]

J: Can you take a guess when your brain sorts such information out of your dreams? Fariha: During dreams?

[03:20]

J: Exactly. This is the housekeeping I was referring to. Dreaming is a way our brain is shuffling information. It's cleaning up the day's information overload. It puts the necessary stuff on the long term shelves and the irrelevant information in the trash bin.

[03:37]

Navika: Oh, this makes sense. That is why we're always told to get a good night's sleep before exams. So our brain gets sufficient time to organize all the information that we have learned into a long-term memory.

[03:51]

Satakshi: But is there a name for this physical space or draw for the storage of memory?

[03:58]

NC: In mammals, the hippocampus seems to have a specific role in this. So there was this patient in which this particular hippocampus was removed due to epileptic seizures thinking that this will help him. But what resulted was he remembered everything before the operation. But after the operation, he couldn't remember anything beyond a few minutes. And I think there was even a film on this. But the idea is that because of his effect on his hippocampus, he was not able to take those short term associations, short term memory, (like even memory of people, memory of places) to its long term consolidation. That process kind of got affected because of removal of this one really small part of the brain.

[4:50]

Fariha: But what information sorting has got to do with dreams?

[04:55]

J: So when your brain is trying to organize the information in special compartments in the brain, it basically has to replay the information and this information may leak out as dreams.

[05:09]

Satakshi: Oh, that's interesting. But then this does not explain all the weird bizarre dreams we have. Right?

[05:18]

J: Oh Yes. Those dreams where you can't explain why you are suddenly sitting in your classroom wearing your night dress?

[05:25]

Satakshi: Exactly, those ones.

J: This could happen when your brain is trying to reorganize multiple sets of information at one time. Like it is multitasking with many memories. This part usually happens during the REM sleep or rapid eye movement sleep. This sleep phase as the name suggests is characterized by rapid eye movements. It usually happens closer to the time you wake up. You must have seen this in movies or TV shows when the actor is having a bad dream, they are moving their eyes left to right.

[06:02]

Fariha: But wait, is it possible that we only remember the bizarre dreams more often than the boring regular dreams?

[06:10]

J: Yes, that is very much likely.

[06:13]

Fariha: I wonder why that happens?

[06:17]

J: It's possible bizarre dreams have more emotions involved. Like in our regular waking life, we remember events that were more emotional for us. The same thing happens in dreams as well. The same part of the brain which is active during the day in such emotional events is also active in our sleep while we are having dreams.

Satakshi: All in all, it seems like dreams help us in a lot of important brain functions like memories, emotions and creativity.

[06:46]

Fariha: This makes me think we all sleep, right? Birds, dogs, elephants, horses, cats, et cetera. Then do we all dream?

[06:57]

J: Yes. Birds and mammals also dream. And that's why there is an emerging theory that says that dreaming might actually have some evolutionary function just like sleep does

Navika: And these dreams wouldn't occur without sleep. I wonder what would happen if we didn't sleep?

[07:18]

NC: The whole idea behind why we sleep itself, we do not understand completely, right? This is a state where you are keeping yourself vulnerable to external threats for a better part of your lifetime. We know that if we don't sleep, there will be certain abnormalities that we can face over the short term and even and also the long term, which includes physiological dysfunctions and cognitive dysfunctions. But again, why is sleep relevant for that? Why just not lying down and resting is sufficient? That again is quite debatable.

[07:56]

U: As the curious group understood the importance of dreams and sleep. They now wanted to know how Dr Chouhan studies sleep in his lab.

[08:08]

J: How did you decide to choose Drosophila as a model for sleep?

[08:12]

NC: Drosophila. What is good about them is you can really manipulate each and every aspect of their biology. You can manipulate each and every neuron, you can manipulate each and every gene. So that gives you a lot of flexibility to study whatever process you are interested in studying. And a lot of these mechanisms that are being first looked into flies are also conserved in higher organisms including humans. Now, of course, you cannot put electrodes in the Drosophila head and try to recall. And the other aspect is that if you are unable to sleep, if I keep you awake the whole night, then the next day, you will tend to sleep even during the day, that's the rebound effect that is coming into the picture. In similar fashion if we keep flies awake through mechanical means to not let them stop moving then the next day they show again this rebound sleep-like state.

[09:02]

J: Like how did you get interested in sleep as a question and as an area of research? Was this something that you always were inclined towards or did it happen eventually as you studied at IISER and went ahead from there?

[09:16]

NC: I actually come from a family which has not produced any PhDs before. So this line of questioning or this line of career was never on the cards. It was you get through your 12th and start preparing for some engineering or medicine exam and move in that direction. But fortunately I ended up at IISER for one reason or the other. And what fascinated me right from the beginning was studying behavior, how behavior changes through experience. For that I started working with flies because it's a very simple system to get started with. That kind of got me interested. I started studying attraction first. I think it just built from there one behavior after the other. I just, it just made me more curious about how the behavior is executed.

[10:08]

U: How does your lab look like? Is it something that we want to know? Like do you have bottles full of fruit flies or like how does it look?

[10:16]

NC: Yeah. So we do have bottles full of fruit flies. We grow them in thousands. But in addition to growing fruit flies, we also have dedicated spaces to do behavior. So we have designed specific boxes. These are big boxes in which you can walk into and do your experiments. So those are really controlled environments in which these experiments are done. But in addition, we also do imaging studies where we record from the brain. Even in tiny fruit flies, we have sophisticated microscopes available that can help us record neural activity changes. So once they form memory or they sleep, we record from those neurons and see which area of the brain might be involved and to pinpoint which neurons might be playing a role in the particular process.

[11:04]

Navika: I wanted to ask, how do you study food flies when they are so small?

[11:08]

NC: So they do require very gentle handling to move them from one type of food to the other type of food, to do learning memory experiments with them. But they are, I would say they're also quite robust, they don't like die easily. So if you are gentle with your handling, if you are moving things properly, most of the experiments we do, we anesthetize our flies. We use some sort of chemical so that they are not moving, so then we can move them from one place to the other and do experiments. But a lot of behavior experiments are done with moving flies, of course. So it requires a little bit of training, but it's way easier than you would think.

[11:51]

J: What are some of these tips or anything that they should remember, keep in mind to build a career beyond engineering and medicine, probably?

[11:57]

NC: Probably so I can understand the peer pressure. I myself have experienced it when everybody wants to do one or two things, then that becomes a norm in the society. And in general, people would go in that direction. So I would say to keep an open mind, one thing would be to read a little bit about science. Every newspaper carries science columns, there are science documentaries. So if you just go ahead and read and watch that itself will tell you how this is being done and what progress we are making. Each and every word written in it is there because of work done by some scientists somewhere, right? So that immense contribution would not be there if everybody would have just done engineering and medicine. There's nothing wrong in doing that, of course. But if you are more curious to answer or to ask questions, you're more into answering, you know, for instance, why we dream and why we sleep and… These are just some of the questions. But there are so many, all these things can only happen if you let yourself experience the other side as well. So just keep your mind broad, read about it and that will give you an alternative, at least to what everybody else is saying you should or shouldn't do.

[13:18]

J: So what did we learn today?

[13:21]

U: Dreams are connected to memories. So, while we are sleeping, our brain routinely organizes information into long and short term memories as a part of its housekeeping. Sometimes when the brain is organizing multiple sets of information at the same time, information tends to get leaked. This leaked information is what manifests as dreams during our sleep. Oh. And we tend to remember bizarre dreams more often because they have more emotions involved.

[13:54]

J: Exactly. And we also spoke to Dr Nitin Chouhan, a scientist who studies sleep and Drosophila. He first spoke to us about the hippocampus, the part of the brain where the information gets organized. His lab is full of fruit fly jars and boxes to study the flies' behaviors.

[14:13]

U: Isn't that super cool? Finally, Dr Chouhan told us to keep an open mind when it comes to choosing our careers and read more to understand how science works.

[14:24]

J: But listeners, what we know about sleep and dreams might change as we get more evidence over time.

[14:32]

U: Who knows one of our listeners might study sleep and dreams in the future to find out something that we never knew before.

[14:42]

U: That's it for today. If you enjoyed listening to our episodes, make sure to visit our website. www.indiaaskswhy.org for more content. You'll find illustrations, transcripts, blogs and scientist profiles for all of our episodes.

[15:01]

J: We are sure we must have sparked your curiosity. You can submit all your questions on our website and get a chance to be featured in one of our episodes.

[15:12]

U: Follow us on Instagram and Twitter for more updates. Link in the show notes.

J: India asks why it is funded by India Bioscience Extension Grant.

U: Shweata N Hegde and Ruchi Maglunia are the hosts of the podcast. Kaviranjana Anthony audio-edited the episode and Khushi Goel transcribed it. Also thanks to all our team members for enabling Utsuka and Jigyasa to chase their curiosity.

[15:39]

J: Special thanks to Navika, Satakshi and Fareeha for joining us and a big shout out to Delhi public school, Secunderabad and their teachers for making this possible.

[15:48] U: Finally, thanks to Dr Nitin Chouhan for answering all the curious questions we posed.

[15:54] J: Until next time. Till then, stay tuned and stay curious.