Topic-initiating statement

These statements are signified as topic-initiating while the explainer/explainee refers to a new topic within their statement or comment. These statements might be accompanied by an elaborative description.

-Explainee: ['I never knew beforehand how hard it was', 'to get actual data of the black holes itself,', "first of all, they're dark, and, like,", "they're so far away, it's almost impossible just", 'to get a good image of them.', 'They were discussing a project in', 'which multiple radio telescopes of some sort, like, are,', 'like, pinpointed all across, from Greenland', "to South America, and, like, and they're trying to", 'get an image of', 'the black hole in the center', 'of our galaxy because, as opposed', 'to just recording its impact', 'on the surrounding stars and planets.']
-Explainer: [So we've been, we've had, now,", 'effectively two different ways', 'of getting more direct measurements, one is the LIGO, which', 'is the Laser Interferometer Gravitational Wave Observatory,', 'which is where, getting the ripples in space time,', 'coming off of the merging of black holes.', "The other one that you're mentioning is actually called", "the Event Horizon Telescope, where they're using radio waves", 'to actually image the event horizon,', 'that region where light cannot escape', 'from the black hole at the center of our galaxy,', "which I know they're working on it right now.", "It's an amazing thing,", "but that'll be the most direct imaging of a black hole.", 'LIGO is a direct detection of the consequence', 'of the merging of black holes.', 'The critical part has been, like,', 'for the super massive black hole at the center', "of our galaxy, we've seen the stars orbiting it,", "and we've measured the mass, so that way,", 'so if you look at a spinning black hole,', 'it actually fundamentally alters the emission', "that's coming off the stuff that's falling into it.", 'These are discovered as what are called X-ray binaries,', "that is, you know, there's an X-ray member", 'of the binary that is emitting in the X-rays,', "and it's really not very bright", "in the optical (mumbles) at all, so there's always,", 'people are looking at these X-ray binaries.']--->Topic-initiating statement

 -Explainer:["So that's good, because that's why you're here,", "and so we're talking about sleep today,", 'and really about kind of what is the brain machinery', 'through which we go through consciousness', 'to unconsciousness and that transition.']
 -Explainee: [Great.]
 -Explainer:' ['Okay.', The best way to think about this transition', "is really called, it's a flip flop switch, okay?", 'So this term comes from engineering,', 'and the idea is that in sleep,', 'you basically have kind of this all of nothing experience.', 'Certainly people kind of drift off to sleep,', "but then all of a sudden you're unconscious, right?", "So it seems like it's this flip flop between", 'the arousal system and the sleep promoting system,', "and it's certainly regulated,", "and we'll get a little bit into that,", "but they're certainly kind of made up", 'of two reciprocally inhibitory processes.', 'Okay, so we have the ascending reticular activating system.', 'It originates in the brain stem,', "and there's a dorsal and a ventral arm to this,", 'and so the dorsal arm has neurons, cholinergic neurons,', 'that go up to the thalamus', 'and then it projections into the fore brain,', "and then there's the ventral arm,", 'and this is comprised of a whole bunch', 'of different types of neurons,', 'so there are monominergic,', "so there's kind of dopaminergic neurons", 'that come from the periaqueductal gray,', 'serotonergic ones from the dorsal raphae nuclei,', 'histaminergic neurons that come', 'from the tuberomammillary nucleus of the hippothalamus,', 'and then noradrenergic neurons', 'from the locus coeruleus,', 'and so all of those are kind of working in tandem', 'to kind of drive wake within the brain.', 'So if we just think about drugs that are available', 'inducing wakefulness, we can certainly,', 'kind of the dopaminergic ones jump out, right?', 'So we have amphetamines that kind of drive those signaling,', 'and then modafinil, which is a wake promoting drug', 'for people that have kind of excessive day-time sleepiness', 'that maintains alertness throughout the day.'] --->Topic-initiating statement