WEBVTT 00:00:05.000 --> 00:00:10.720 Come on. Okay. So we're going to talk about serotonin. 00:00:11.140 --> 00:00:14.019 Serotonin is kind of an underrated unknown role 00:00:14.019 --> 00:00:18.179 maybe even through pregnancy. People often know 00:00:18.179 --> 00:00:22.000 about serotonin later in life as a neuromodulator 00:00:22.000 --> 00:00:27.100 for being responsible for things like mood and 00:00:27.100 --> 00:00:29.460 appreciating and liking what you have type of 00:00:29.460 --> 00:00:33.789 things like that but It does a lot more. It does, 00:00:33.789 --> 00:00:36.810 um, especially in this timeframe here through 00:00:36.810 --> 00:00:39.170 the different trimesters and through, we'll basically 00:00:39.170 --> 00:00:41.590 get up to the, like the critical period here, 00:00:41.590 --> 00:00:45.229 but we'll start with neuralation because we'll 00:00:45.229 --> 00:00:47.350 have to, because we're developing the living 00:00:47.350 --> 00:00:51.590 organism. One thing to know about serotonin is, 00:00:51.590 --> 00:00:56.070 um, it comes from tryptophan, which is an aromatic 00:00:56.070 --> 00:01:00.509 amino acid. The human body has 20 amino acids 00:01:00.509 --> 00:01:03.219 and You can see these broken down into different 00:01:03.219 --> 00:01:07.859 kind of subtypes. The aromatic type, tryptophan, 00:01:07.980 --> 00:01:12.000 tyrosine, and phenylalanine are very diverse. 00:01:12.219 --> 00:01:17.420 Tryptophan is similar to methionine because it 00:01:17.420 --> 00:01:20.299 only has one codon. They're building block proteins. 00:01:20.939 --> 00:01:24.780 So it makes sense that this building block protein 00:01:24.780 --> 00:01:28.719 will be responsible for developing the living 00:01:28.719 --> 00:01:34.120 organism. from the get go. Dr. Hannah Stevens 00:01:34.120 --> 00:01:39.299 from the University of Iowa. She is an MD, PhD. 00:01:39.540 --> 00:01:42.500 She studies kind of this timeframe. She's also 00:01:42.500 --> 00:01:46.379 a clinical doctor and she's a neuroscientist. 00:01:46.459 --> 00:01:49.079 What led me to her is the dorsal striatum because 00:01:49.079 --> 00:01:51.299 of the basal ganglia. We have a lot of episodes 00:01:51.299 --> 00:01:55.060 on the basal ganglia, but she studies this timeframe. 00:01:56.599 --> 00:02:00.049 And you know, she's just fantastic. She has such 00:02:00.049 --> 00:02:11.530 fantastic roles and research with autism. So 00:02:11.530 --> 00:02:15.330 basically, what we're going to mainly talk about 00:02:15.330 --> 00:02:18.849 is developing the sensory map. That's our end 00:02:18.849 --> 00:02:22.289 goal. We're going to talk about the somatosensory 00:02:22.289 --> 00:02:25.689 cortex, which is right about here, the visual 00:02:25.689 --> 00:02:29.319 cortex, and then audition the auditory cortex 00:02:29.319 --> 00:02:36.300 v1 and x1 are not as dominant here with the serotonin's 00:02:36.300 --> 00:02:41.280 role as s1 map but let's get there the first 00:02:41.280 --> 00:02:45.780 trimester remember this is uh remember the episodes 00:02:45.780 --> 00:02:49.400 about neuralation just real quick here also about 00:02:49.400 --> 00:02:51.860 tryptophan is there's two different distinct 00:02:51.860 --> 00:02:56.409 pathways of tryptophan and At this time frame, 00:02:56.469 --> 00:02:59.129 that's not so much the case because the fetus 00:02:59.129 --> 00:03:03.969 has nothing. It's just helping develop. So, T 00:03:03.969 --> 00:03:08.729 synthesizes tryptophan in the peripheral and 00:03:08.729 --> 00:03:11.969 enteric nervous system. Tryptophan hydroxylase 00:03:11.969 --> 00:03:15.610 -1. Remember, anytime you hear ACE or C -ACE, 00:03:15.770 --> 00:03:19.069 A -S -C, it's an enzyme. Then the brain is T 00:03:19.069 --> 00:03:25.370 -P -H -2. These don't cross over. in the developing 00:03:25.370 --> 00:03:31.370 organism. But at this time, now this is kind 00:03:31.370 --> 00:03:33.610 of drawn out and developed, but we're in the 00:03:33.610 --> 00:03:36.189 first trimester here, before neurolation and 00:03:36.189 --> 00:03:42.449 everything. Serotonin and tryptophan's role here 00:03:42.449 --> 00:03:49.590 is just kind of providing neurogenesis and later 00:03:49.590 --> 00:03:52.669 on a little bit of synaptogenesis because remember 00:03:52.669 --> 00:04:02.889 the The neuralation. Remember we have neuroepithelial 00:04:02.889 --> 00:04:05.110 cells. There's four of them that make the central 00:04:05.110 --> 00:04:07.949 nervous system. And that's what we're gonna have 00:04:07.949 --> 00:04:10.889 to talk about here. But we're gonna get there. 00:04:11.810 --> 00:04:17.750 Remember the four neuroepithelial cells. Proencephalon. 00:04:20.370 --> 00:04:24.040 Proencephalon, no, mesencephalon. mesencephalon 00:04:24.040 --> 00:04:27.939 the one that doesn't subdivide and then the rhombencephalon 00:04:27.939 --> 00:04:33.899 and then this will later develop this will later 00:04:33.899 --> 00:04:41.199 subdivide into telencephalon for the cortex showing 00:04:41.199 --> 00:04:47.899 up not bad diencephalon for the subcortical areas 00:04:47.899 --> 00:04:50.680 and the eyes will extend out from the diencephalon 00:04:50.910 --> 00:04:54.329 the mesencephalon here in the midbrain remember 00:04:54.329 --> 00:04:58.050 from yeah we have a lot of episodes about the 00:04:58.050 --> 00:05:01.750 mesencephalon because it doesn't subdivide and 00:05:01.750 --> 00:05:05.170 it has three main roles that is trying to achieve 00:05:05.170 --> 00:05:09.350 one is sensory integration two is motor movements 00:05:09.350 --> 00:05:13.170 and three is kind of orienting the attention 00:05:13.170 --> 00:05:17.569 of the living organism to the outside world so 00:05:17.569 --> 00:05:21.649 that is why The mesencephalon is very fascinating 00:05:21.649 --> 00:05:24.009 to me because all three of those are autism. 00:05:25.089 --> 00:05:29.350 And then the ROM encephalon subdivides into the 00:05:29.350 --> 00:05:33.829 MET and the MY encephalon. So things like the 00:05:33.829 --> 00:05:37.870 pons cerebellum and then the MY encephalon for 00:05:37.870 --> 00:05:46.569 the medulla and then the spine. Why this is going 00:05:46.569 --> 00:05:52.379 to be important here is because where serotonin 00:05:52.379 --> 00:05:55.560 is later made in the brain remember because it 00:05:55.560 --> 00:05:59.040 doesn't cross over it's going to be important 00:05:59.040 --> 00:06:02.319 here right here with the brain stem but we have 00:06:02.319 --> 00:06:07.620 to first develop it let's see what else is important 00:06:07.620 --> 00:06:12.000 here we've talked about things like sonic hedgehog 00:06:12.000 --> 00:06:24.680 and p10 and then this phosphorus phosphorus and 00:06:24.680 --> 00:06:28.639 with the mTOR rapamycin and then this right here 00:06:28.639 --> 00:06:32.980 is like kind of a metabolic regulator of it and 00:06:32.980 --> 00:06:35.699 sonic hedgehog and things because we're developing 00:06:35.699 --> 00:06:39.819 the cells we have there's massive amounts of 00:06:39.819 --> 00:06:43.660 cells dividing here and they're just explotential 00:06:43.660 --> 00:06:49.139 there's so many cells happening serotonin is 00:06:49.139 --> 00:06:55.709 kind of regulating that So we're getting to Neuralation 00:06:55.709 --> 00:07:00.389 here not much is happening here as far as Developing 00:07:00.389 --> 00:07:03.089 the organs and so forth the tissues of the brain 00:07:03.089 --> 00:07:09.149 the central nervous system But okay, so Yeah, 00:07:09.149 --> 00:07:12.410 the fetus here. Let's just touch on this real 00:07:12.410 --> 00:07:15.329 fast because I think we'll just draw this out 00:07:15.329 --> 00:07:19.779 about the sources of the serotonin the first 00:07:19.779 --> 00:07:23.500 trimester this neurolation obviously there's 00:07:23.500 --> 00:07:26.879 nothing there that the baby can make the fetus 00:07:26.879 --> 00:07:29.800 can make so it gets all of it from the maternal 00:07:29.800 --> 00:07:34.620 maternal tph1 the peripheral and her enteric 00:07:34.620 --> 00:07:38.079 people would be maybe shocked to know that 95 00:07:38.079 --> 00:07:45.959 or so of our serotonin is in the gut so the gut 00:07:46.170 --> 00:07:49.709 serotonin tryptophan of the maternal here is 00:07:49.709 --> 00:07:53.470 vastly important because now she has to supply 00:07:53.470 --> 00:07:58.269 materials kind of building block materials here 00:07:58.269 --> 00:08:02.170 for the placenta the umbilical cord and then 00:08:02.170 --> 00:08:06.730 to the fetus remember what um the tryptophan's 00:08:06.730 --> 00:08:09.970 role here with the placenta is if we were going 00:08:09.970 --> 00:08:13.930 to we're not really subordinating or breaking 00:08:13.930 --> 00:08:17.939 these out but As far as the molecule building 00:08:17.939 --> 00:08:21.860 block for the placenta, tryptophan might be number 00:08:21.860 --> 00:08:24.360 one. Remember, it's a building block with that 00:08:24.360 --> 00:08:28.879 one codon and methionine. So it's vastly important 00:08:28.879 --> 00:08:31.540 to hear the maternal's tryptophan and serotonin 00:08:31.540 --> 00:08:36.799 levels. It's very delicate because of the roles 00:08:36.799 --> 00:08:41.100 with the neurogenesis and so forth. So all of 00:08:41.100 --> 00:08:44.259 it from the first trimester, it's coming from 00:08:44.259 --> 00:08:47.240 the maternal nothing from the fetus it can't 00:08:47.240 --> 00:08:49.659 we just drew out what looks like little peas 00:08:49.659 --> 00:08:53.879 nothing's happening then however we get to the 00:08:53.879 --> 00:08:57.659 second trimester and things start to kind of 00:08:57.659 --> 00:09:00.799 shape all these tissues and brain regions what 00:09:00.799 --> 00:09:05.200 we're going to get to begin taking shape okay 00:09:05.200 --> 00:09:08.159 so something that we've talked a lot about is 00:09:08.159 --> 00:09:11.340 the many columns because that's what it's going 00:09:11.340 --> 00:09:14.159 to make these sensory maps or the many columns 00:09:14.159 --> 00:09:16.659 again and the thalamus we talked a lot about 00:09:16.659 --> 00:09:20.480 the thalamus remember it's a sensory relay station 00:09:20.480 --> 00:09:25.360 and it's vastly important here and the serotonin 00:09:25.360 --> 00:09:30.460 and the sensory map is that tissue the thalamus 00:09:30.460 --> 00:09:36.399 and these sensory cortexes s1 v1 and a1 but remember 00:09:36.399 --> 00:09:41.179 more s1 So serotonin's role here, let's just 00:09:41.179 --> 00:09:45.419 draw this out. Let's just draw this out in a 00:09:45.419 --> 00:09:49.019 way that kind of makes sense to us. Something 00:09:49.019 --> 00:09:52.600 that we've seen before in the other videos, the 00:09:52.600 --> 00:09:57.120 thalamus. Yeah, so we have the medial geniculate 00:09:57.120 --> 00:10:01.039 right here, the relay station for audition, the 00:10:01.039 --> 00:10:04.860 lateral geniculate, the relay station for vision. 00:10:05.840 --> 00:10:08.419 And then the rest of the tissue that makes up 00:10:08.419 --> 00:10:11.259 the thalamus. Okay. Remember it has the shell 00:10:11.259 --> 00:10:14.080 over it too. That's going to be involved here. 00:10:14.940 --> 00:10:19.039 But we're going to kind of go before that shell 00:10:19.039 --> 00:10:23.500 somewhat. So let's just think about this as a 00:10:23.500 --> 00:10:27.360 thalamus. This is the view from like overhead 00:10:27.360 --> 00:10:30.519 and from the back because these are in the posterior 00:10:30.519 --> 00:10:35.200 and inferior parts. Remember The midbrain is 00:10:35.200 --> 00:10:39.340 just below here. And these things can just reach 00:10:39.340 --> 00:10:42.779 out and high five each other because of they're 00:10:42.779 --> 00:10:47.299 organizing for fast. First order sensory processing. 00:10:48.179 --> 00:10:51.919 That's the whole thing we're talking about. So 00:10:51.919 --> 00:10:56.639 the second trimester and so forth, these things 00:10:56.639 --> 00:11:00.080 began taking shape. They're being structured. 00:11:00.559 --> 00:11:05.340 And serotonin here is kind of regulating the 00:11:05.340 --> 00:11:12.559 building block of this. So the fetus will begin 00:11:12.559 --> 00:11:15.840 supplying its own, remember, because all of the 00:11:15.840 --> 00:11:20.059 cell dividing and we've now mapped out the central 00:11:20.059 --> 00:11:24.559 nervous system with that neurolation. So the 00:11:24.559 --> 00:11:28.379 second trimester, the fetus begins to making 00:11:28.379 --> 00:11:32.779 its own and it's kind of helping regulate the 00:11:32.779 --> 00:11:36.340 nutrients and so forth, the physiology of the 00:11:36.340 --> 00:11:40.399 umbilical cord, and then the placenta. If I didn't 00:11:40.399 --> 00:11:43.620 mention, I don't remember if I did or not, but 00:11:43.620 --> 00:11:46.440 remember the episode where Dr. Eric Weiss, he's 00:11:46.440 --> 00:11:50.000 a surgeon, I believe an orthopedic surgeon, and 00:11:50.000 --> 00:11:55.700 he's now shifting his role as an MD to more stem 00:11:55.700 --> 00:12:00.529 cell research. umbilical cord stem cells to treat 00:12:00.529 --> 00:12:03.509 autism. And he did it on his son, Marston. You 00:12:03.509 --> 00:12:06.190 can see their story. I'm not pushing it, but 00:12:06.190 --> 00:12:10.789 he happened to kind of naturally get into the 00:12:10.789 --> 00:12:13.590 stem cell research because of his, he went to 00:12:13.590 --> 00:12:16.389 Duke School of Medicine and they do some of that 00:12:16.389 --> 00:12:20.049 stuff there. And at his residencies, he met other 00:12:20.049 --> 00:12:23.210 doctors and research programs that do this for 00:12:23.210 --> 00:12:25.809 other conditions. He's like, well, why not do 00:12:25.809 --> 00:12:29.820 it for autism? He done it with his son Marston. 00:12:29.820 --> 00:12:34.720 You can see their story but anyway the second 00:12:34.720 --> 00:12:39.679 trimester The fetus in orange begins to make 00:12:39.679 --> 00:12:42.720 more Maternals is still going to be pretty high 00:12:42.720 --> 00:12:46.519 though, but not as much. It's not as required 00:12:46.519 --> 00:12:54.440 So if this is the thalamus we have to get to 00:12:54.440 --> 00:12:59.580 the cortex especially S1. Now, I'm not so sure 00:12:59.580 --> 00:13:02.639 how we're gonna map this out, to be honest. Because 00:13:02.639 --> 00:13:05.220 I really want to, I think I'll draw a lateral 00:13:05.220 --> 00:13:12.299 view of it too. Something that we've, we know 00:13:12.299 --> 00:13:16.919 is, you got the eyes and then the thalamus here, 00:13:17.360 --> 00:13:21.580 basically in the middle, deep inside. And then 00:13:21.580 --> 00:13:33.420 we have things like the brain stem, Cerebellum. 00:13:33.420 --> 00:13:41.299 And the occipital. Up to the parietal. The sensory 00:13:41.299 --> 00:13:43.379 motor area, which is where we're gonna spend 00:13:43.379 --> 00:13:50.500 a lot of time. Getting up into the prefrontal 00:13:50.500 --> 00:13:54.740 cortex. And then just to make sense of where 00:13:54.740 --> 00:14:05.120 we are, the temporal lobe. so we're kind of looking 00:14:05.120 --> 00:14:19.899 like this okay and then if we just want to kind 00:14:19.899 --> 00:14:25.100 of make sense of the s1 area and also m1 because 00:14:25.100 --> 00:14:28.600 we're going to kind of map out the homunculus 00:14:28.600 --> 00:14:32.039 the homunculus is going to be mentioned and we're 00:14:32.039 --> 00:14:36.419 going to I think maybe I'll draw it out. So S1 00:14:36.419 --> 00:14:47.299 is back through here. Kind of slanted. So somatosensory 00:14:47.299 --> 00:14:53.220 1 is like right there. And then the motor cortex 00:14:53.220 --> 00:14:58.559 M1 is just in front of it. Remember this area 00:14:58.559 --> 00:15:02.049 right here is sensory motor. Remember we have 00:15:02.049 --> 00:15:04.309 the frontal eye fields up here and there's the 00:15:04.309 --> 00:15:08.450 supplemental motor area SMA up here. All of our 00:15:08.450 --> 00:15:12.049 reflexes and habits kind of go here. Remember 00:15:12.049 --> 00:15:15.250 it conserves energy and the brain number one 00:15:15.250 --> 00:15:18.549 goal is to conserve and allocate energy. Based 00:15:18.549 --> 00:15:22.110 off of the sensations coming in it's going to 00:15:22.110 --> 00:15:26.269 determine what do I need to activate and inactivate 00:15:26.269 --> 00:15:30.230 while conserving energy. That's why habits are 00:15:30.509 --> 00:15:38.230 So powerful So at this second trimester So this 00:15:38.230 --> 00:15:40.470 is the thalamus here and we're going to start 00:15:40.470 --> 00:15:43.750 building up cells and connections because serotonin 00:15:43.750 --> 00:15:46.990 is main role here is the connections the so -called 00:15:46.990 --> 00:15:52.149 wiring that Will provide these things to communicate 00:15:52.149 --> 00:15:55.149 remember these are kind of distal areas here 00:15:55.149 --> 00:15:58.960 So these distal connections things like white 00:15:58.960 --> 00:16:02.299 matter tracks and so forth are important. Remember 00:16:02.299 --> 00:16:07.539 the many columns too. So let's just draw out 00:16:07.539 --> 00:16:09.220 some of the many columns because we're going 00:16:09.220 --> 00:16:12.659 to talk about the differences between a properly 00:16:12.659 --> 00:16:15.539 structured many column and remember the neuro 00:16:15.539 --> 00:16:26.330 feel. So let's just get into this. Remember these 00:16:26.330 --> 00:16:30.090 are layers of the cortex. We have six layers 00:16:30.090 --> 00:16:32.830 in the cortex. They basically stack upon each 00:16:32.830 --> 00:16:36.590 other like this, like crepes. They're basically 00:16:36.590 --> 00:16:45.610 just like six crepes stacked together. We're 00:16:45.610 --> 00:16:49.149 going to talk about two that we've already talked 00:16:49.149 --> 00:16:51.809 a lot about. So this is good that we have this 00:16:51.809 --> 00:16:54.330 background information and videos about this. 00:16:56.209 --> 00:18:10.470 Remember, let me draw this out here. So let's 00:18:10.470 --> 00:18:13.650 look at this mini column here, okay? So we have 00:18:13.650 --> 00:18:15.829 a mini column here, and then we have another 00:18:15.829 --> 00:18:18.130 mini column here. Remember, as we build mini 00:18:18.130 --> 00:18:20.789 columns, they're macro columns. Then we have 00:18:20.789 --> 00:18:24.470 this space in between, not Dave Matthews, but 00:18:24.470 --> 00:18:31.549 this kind of space in between here is called 00:18:31.549 --> 00:18:35.970 neurofeel. Okay, remember, with the autistic 00:18:35.970 --> 00:18:39.529 phenotype, these are smaller roughly 40 50 60 00:18:39.529 --> 00:18:45.430 microns versus a typical just 80 to 90 100 microns 00:18:45.430 --> 00:18:49.390 or so so the difference of a thickness of the 00:18:49.390 --> 00:18:53.089 sheet of paper is about 90 to 100 microns the 00:18:53.089 --> 00:18:55.829 autistic phenotypes is half a thickness of a 00:18:55.829 --> 00:18:59.829 sheet of paper we're going to get to why serotonin 00:18:59.829 --> 00:19:03.690 is important for this creation and some of the 00:19:03.690 --> 00:19:08.970 regions of the thalamus But first to recap we've 00:19:08.970 --> 00:19:15.069 already talked about it probably a lot this Connections 00:19:15.069 --> 00:19:19.829 come from the thalamus and enter layer 4 This 00:19:19.829 --> 00:19:25.950 is called Thalamocortex This is thalamocortex 00:19:25.950 --> 00:19:30.990 thalamus to the cortex landing spot is L4 layer 00:19:30.990 --> 00:19:38.230 4 Layer 2 and 3 we'll get next right we've talked 00:19:38.230 --> 00:19:40.269 about this so i won't spend a whole lot of time 00:19:40.269 --> 00:19:43.869 here because that's where our experiences and 00:19:43.869 --> 00:19:47.029 our intelligence everything we know our skill 00:19:47.029 --> 00:19:49.789 sets and everything live kind of layer two and 00:19:49.789 --> 00:19:55.309 three so sensory information is coming up then 00:19:55.309 --> 00:20:00.190 recruits l two three four kind of what do i do 00:20:00.190 --> 00:20:03.009 and then they're sending instructions back down 00:20:04.970 --> 00:20:11.410 Two layer five and six, four. A big layer about, 00:20:11.529 --> 00:20:14.990 I should just say it then, I guess. Five and 00:20:14.990 --> 00:20:17.650 six have two different kind of layers. Five A, 00:20:17.750 --> 00:20:26.990 five B, six A, six B. The one with six is speaking 00:20:26.990 --> 00:20:33.089 back down to the thalamus. So corticothalamic. 00:20:33.710 --> 00:20:36.730 Right, we've talked about this, but I think we're 00:20:36.730 --> 00:20:41.630 gonna have to map this out so that we know Remember 00:20:41.630 --> 00:20:44.009 below six is a bunch of white matter tracks. 00:20:44.309 --> 00:20:51.190 Okay, so the second trimester and and beyond 00:20:51.190 --> 00:20:55.470 serotonin is kind of providing wire diagrams 00:20:55.470 --> 00:20:59.269 because these connections must communicate and 00:20:59.269 --> 00:21:01.769 the way that they communicate or things like 00:21:01.769 --> 00:21:04.920 axons and these so -called connections and so 00:21:04.920 --> 00:21:09.819 forth so what is happening at this second trimester 00:21:09.819 --> 00:21:13.039 because there's not a lot of sensory input for 00:21:13.039 --> 00:21:16.859 the child and so forth it's just kind of building 00:21:16.859 --> 00:21:19.579 these structures here just putting them in the 00:21:19.579 --> 00:21:23.099 right place remember the differences between 00:21:23.099 --> 00:21:27.660 proliferation differentiation and migration so 00:21:27.660 --> 00:21:30.759 the second trimester here is a lot of neurogenesis 00:21:30.759 --> 00:21:34.960 and then migration serotonin is responsible for 00:21:34.960 --> 00:21:38.859 the areas of the thalamus in this s1 the relay 00:21:38.859 --> 00:21:42.980 stations like for sensory v1 back here a1 up 00:21:42.980 --> 00:21:50.160 here so it's very important that these things 00:21:50.160 --> 00:21:54.960 are being built it's almost like i like st peter's 00:21:54.960 --> 00:22:00.000 basilica i won't rant but i like st peter's basilica 00:22:00.000 --> 00:22:04.160 and Serotonin here is like Michelangelo or Bernini. 00:22:04.279 --> 00:22:07.240 It's like the architecture. It's determining 00:22:07.240 --> 00:22:11.579 what goes where. So whenever this is kind of 00:22:11.579 --> 00:22:15.119 abnormal, things start to become complicated 00:22:15.119 --> 00:22:19.960 already. And this is very, this is, this is challenging. 00:22:20.079 --> 00:22:22.099 This is because we're going to talk a lot about 00:22:22.099 --> 00:22:25.140 the sensory overload and just it's chaotic and 00:22:25.140 --> 00:22:30.400 so forth. There's a thing called diffusion. and 00:22:30.400 --> 00:22:33.059 at this time point right here whenever these 00:22:33.059 --> 00:22:36.660 things are being built and these connections 00:22:36.660 --> 00:22:40.220 are being made as we're heading especially into 00:22:40.220 --> 00:22:43.759 the third trimester there's a little crossover 00:22:43.759 --> 00:22:49.140 here about how much the sources are from where 00:22:49.140 --> 00:22:55.920 so the child will start to kind of supply its 00:22:55.920 --> 00:22:57.859 own because it's you know it's getting bigger 00:22:57.859 --> 00:23:02.230 and bigger What we're doing here is building 00:23:02.230 --> 00:23:07.650 this foundation to get us towards perinatal birth 00:23:07.650 --> 00:23:11.369 and the critical period. There's a lot of sensory 00:23:11.369 --> 00:23:15.950 integration and processing, a lot of physical 00:23:15.950 --> 00:23:21.049 phenomena just smothering these sensory processes. 00:23:22.750 --> 00:23:26.269 So at this point though, there's a thing called 00:23:26.269 --> 00:23:31.299 diffusion and then refinement. serotonin kind 00:23:31.299 --> 00:23:37.619 of is modulating this so we can do this on the 00:23:37.619 --> 00:23:42.039 seesaw because that's a good thing it's always 00:23:42.039 --> 00:23:48.380 good to see things like this so diffusion refinement 00:23:48.380 --> 00:23:54.039 when serotonin is off either high or low at this 00:23:54.039 --> 00:23:59.930 point because of this tph1 tph2 type thing and 00:23:59.930 --> 00:24:03.869 remember that the living organism, the fetus, 00:24:04.109 --> 00:24:07.750 is developing its own so we've definitely developed 00:24:07.750 --> 00:24:10.710 the central nervous system now. Serotonin for 00:24:10.710 --> 00:24:17.849 the brain is made in right here in the brain 00:24:17.849 --> 00:24:22.009 stem the mesencephalon and down into kind of 00:24:22.009 --> 00:24:28.880 the pons area mostly the posterior side of the 00:24:28.880 --> 00:24:33.279 mesencephalon remember we drew this out we kind 00:24:33.279 --> 00:24:36.680 of drew this out the mesencephalon if we would 00:24:36.680 --> 00:24:41.119 just splice the brain stem and kind of look at 00:24:41.119 --> 00:24:42.779 the top of it because that's how you have to 00:24:42.779 --> 00:24:47.920 look at the brain stem and spine we have this 00:24:47.920 --> 00:24:51.539 para -aqueductal gray it's kind of like right 00:24:51.539 --> 00:24:58.549 here and then serotonin So we can move vertically, 00:24:58.849 --> 00:25:01.069 or if we're just looking at it overhead, it's 00:25:01.069 --> 00:25:05.009 basically like right through here. And then it 00:25:05.009 --> 00:25:07.849 will just come up and just sprinkle the brain, 00:25:07.849 --> 00:25:10.690 essentially. There's a lot of connections. Serotonin 00:25:10.690 --> 00:25:14.869 has a lot of receptors versus the other neuromodulators. 00:25:15.549 --> 00:25:18.930 We haven't quite crossed over into the neuromodulator 00:25:18.930 --> 00:25:26.160 yet. So it's still a building block. the third 00:25:26.160 --> 00:25:31.460 trimester and then like perinatal there's a big 00:25:31.460 --> 00:25:37.599 shift here because of growth is one and being 00:25:37.599 --> 00:25:41.019 able to prepare the living organism the child 00:25:41.019 --> 00:25:46.140 to receive the actual physical phenomena of sensation 00:25:46.140 --> 00:25:51.339 sensation perception and whenever the serotonin 00:25:51.339 --> 00:25:55.240 is bad remember the snorifil When serotonin is 00:25:55.240 --> 00:26:01.200 bad, this neurofil will be smaller and there's 00:26:01.200 --> 00:26:04.880 no real good edges anymore. So there's just a 00:26:04.880 --> 00:26:10.339 lot going on here. Serotonin's role here is to 00:26:10.339 --> 00:26:15.380 determine what is important versus what is not. 00:26:15.920 --> 00:26:21.130 What stays versus what is pruned out. So these 00:26:21.130 --> 00:26:25.750 connections remember we drew we extracted a specific 00:26:25.750 --> 00:26:30.089 cell when we talked about OCD and the basal ganglia 00:26:30.089 --> 00:26:35.029 a specific cell here If we just draw out a specific 00:26:35.029 --> 00:26:40.230 cell however, we want it to look like it doesn't 00:26:40.230 --> 00:26:43.049 It's not that important here, but then if we 00:26:43.049 --> 00:26:52.079 zoom in this is zoom into here And we have these 00:26:52.079 --> 00:26:55.779 spines here. Every time this spine receives a 00:26:55.779 --> 00:27:00.500 connection, it will mean essentially the same 00:27:00.500 --> 00:27:04.579 thing. This spine right here doesn't receive 00:27:04.579 --> 00:27:06.660 different connections with different meanings. 00:27:08.160 --> 00:27:11.359 So whenever these things are not pruned, there's 00:27:11.359 --> 00:27:17.839 a lot of confusion. There's a lot of mismatched 00:27:17.880 --> 00:27:22.759 and a lack of direction, a lack of kind of clear 00:27:22.759 --> 00:27:26.900 -cut structure here of how to process sensations. 00:27:27.720 --> 00:27:31.740 And that is diffusion. Diffusion doesn't have 00:27:31.740 --> 00:27:35.779 clear edges with these many columns, which is 00:27:35.779 --> 00:27:41.200 why the neurofil is smaller. Serotonin here has 00:27:41.200 --> 00:27:45.539 to stamp, has to say, cut these connections out. 00:27:48.119 --> 00:27:52.779 versus refinement. Refinement has clear -cut 00:27:52.779 --> 00:27:58.259 edges. They have clear connections. They don't 00:27:58.259 --> 00:28:02.539 have any competing kind of sensations and processes 00:28:02.539 --> 00:28:06.460 to determine what should I pay attention to. 00:28:07.539 --> 00:28:11.380 Diffusion is a lot of different weak connections 00:28:11.380 --> 00:28:14.160 because the more connections you have, the more 00:28:14.160 --> 00:28:18.960 competition there is. So there is very poor spatial 00:28:18.960 --> 00:28:22.640 boundaries and remember we've also drew throughout 00:28:22.640 --> 00:28:27.720 the signal to noise What are you going to pay 00:28:27.720 --> 00:28:32.940 attention to? What is signal to pay attention 00:28:32.940 --> 00:28:42.240 to versus what is noise? so In the autistic phenotype 00:28:42.240 --> 00:28:45.680 a lot of time it looks like this to the environment 00:28:46.349 --> 00:28:52.470 Not inside. Inside the living organism, inside 00:28:52.470 --> 00:28:55.910 the autistic, it's different. There's a lot of 00:28:55.910 --> 00:29:02.549 signal inward. Autism means self. Now this could 00:29:02.549 --> 00:29:05.630 be very much a reason why because the outside 00:29:05.630 --> 00:29:14.869 world is chaotic. So whenever you think about 00:29:15.200 --> 00:29:20.319 this sensory processing. Just to finish up, so 00:29:20.319 --> 00:29:24.500 we have the S1, we don't need little guy anymore, 00:29:24.880 --> 00:29:30.640 so we have S1 somatosensory, which is processed 00:29:30.640 --> 00:29:37.740 here, this connection right here. These mini 00:29:37.740 --> 00:29:41.430 columns are essentially, could be, they're they're 00:29:41.430 --> 00:29:44.089 pretty plug and play if you will except for there's 00:29:44.089 --> 00:29:45.890 a little bit of different changes especially 00:29:45.890 --> 00:29:49.789 with layer four with the mini columns so this 00:29:49.789 --> 00:29:54.730 one for s1 or the v1 the a1 which is up here 00:29:54.730 --> 00:30:00.170 but laterally very lateral and then visual cortex 00:30:00.170 --> 00:30:02.190 back through here obviously in the occipital 00:30:02.190 --> 00:30:13.099 lobe tomato sensory there's a VP and VL row here 00:30:13.099 --> 00:30:16.599 little brain region that's responsible for speaking 00:30:16.599 --> 00:30:20.720 up to the S1 because remember each connection 00:30:20.720 --> 00:30:32.160 means the same thing and then V1 and A1 are Serotonin 00:30:32.160 --> 00:30:35.140 here is involved in here very much with kind 00:30:35.140 --> 00:30:38.200 of mapping out this diagram, but not as much 00:30:38.200 --> 00:30:43.289 as S1 So this is huge here. So if we look at 00:30:43.289 --> 00:30:47.470 S1 and we look at the so -called homunculus, 00:30:48.369 --> 00:30:59.730 you've probably have seen it. Now I have to reverse 00:30:59.730 --> 00:31:08.650 it. It's going to be complicated. It's not bad. 00:31:09.960 --> 00:31:16.940 It's not bad. So if we just splice this out, 00:31:18.140 --> 00:31:20.380 if we just splice this out and then just looked 00:31:20.380 --> 00:31:25.000 at it like this, and you can see these all over 00:31:25.000 --> 00:31:29.339 the internet. They're actually not bad. And then 00:31:29.339 --> 00:31:33.539 for the sensory motor area here, you can see 00:31:33.539 --> 00:31:41.890 it like side by side. So S1, what color we got? 00:31:41.930 --> 00:32:00.230 Blue. And then S1 will receive the information 00:32:00.230 --> 00:32:05.289 about the sensation, place, space and time, spatial 00:32:05.289 --> 00:32:08.859 awareness and things like that. And then right 00:32:08.859 --> 00:32:12.700 next to it is M1, because remember this other 00:32:12.700 --> 00:32:18.259 layer six cortex is cortico -cortex, cortico 00:32:18.259 --> 00:32:21.559 -cortex. So it's speaking across the cortex. 00:32:22.460 --> 00:32:25.279 We receive information about the environment, 00:32:25.339 --> 00:32:28.579 the space, and then we can have these motor movements 00:32:28.579 --> 00:32:33.099 right here. So M1 will help modulate and control 00:32:33.099 --> 00:32:35.500 motor movements. Each one of these sections, 00:32:35.539 --> 00:32:37.660 this is what I'm getting to, each one of these 00:32:37.660 --> 00:32:40.460 sections right here is responsible for different 00:32:40.460 --> 00:32:44.500 areas of the body. Same for the somatosensory. 00:32:45.259 --> 00:32:48.019 You can see great pictures of these. These are 00:32:48.019 --> 00:32:53.279 basic pictures here. So whenever the sensory 00:32:53.279 --> 00:32:56.079 map is abnormal and there are many different 00:32:56.079 --> 00:33:00.670 connections and so forth, The autistic phenotype 00:33:00.670 --> 00:33:03.269 will receive a lot of information here and not 00:33:03.269 --> 00:33:06.910 know what to do with it. It cannot determine 00:33:06.910 --> 00:33:09.589 signal to noise because there's no refinement. 00:33:09.750 --> 00:33:13.829 Remember, refinement is like manicured yard. 00:33:14.089 --> 00:33:17.910 People love doing yard work. Refinement is like 00:33:17.910 --> 00:33:21.009 that. They have nice edges on their bushes and 00:33:21.009 --> 00:33:24.049 nice landscaping and so forth. Diffusion is like 00:33:24.049 --> 00:33:27.549 ivy. If you've ever had ivy, it just grows massively. 00:33:27.759 --> 00:33:32.559 and it's just everywhere. That's diffusion. So 00:33:32.559 --> 00:33:41.180 as we're getting to perinatal and birth, obviously 00:33:41.180 --> 00:33:43.400 there's nothing from the maternal anymore because 00:33:43.400 --> 00:33:48.819 they are separated. We're building up now to 00:33:48.819 --> 00:33:53.099 the critical period and there is a lot of massive 00:33:53.099 --> 00:33:57.630 sensations going on. So a fascinating question 00:33:57.630 --> 00:34:03.069 about autism is of course how it's built but 00:34:03.069 --> 00:34:06.529 is there something to do with the critical period 00:34:06.529 --> 00:34:11.050 that makes it just a learned kind of characteristic, 00:34:11.130 --> 00:34:14.710 a learned phenotype, a learned trait to stay 00:34:14.710 --> 00:34:18.510 inward at this moment? Is there something to 00:34:18.510 --> 00:34:22.710 do with early intervention before the critical 00:34:22.710 --> 00:34:26.000 period? That's why I talk about the things like 00:34:26.000 --> 00:34:28.800 the UCLA paper on the salience network. The salience 00:34:28.800 --> 00:34:32.019 network is how do you modulate your attention? 00:34:32.800 --> 00:34:38.139 And that's why that paper from 2024 UCLA that 00:34:38.139 --> 00:34:42.900 found abnormal connections with the autistic 00:34:42.900 --> 00:34:45.519 phenotype at six weeks old ought to be followed 00:34:45.519 --> 00:34:49.239 up on. There's no nothing ever comes out of it. 00:34:49.639 --> 00:34:52.880 And it's irritating because what if you could 00:34:52.880 --> 00:34:57.760 catch autism With that altered connection, remember 00:34:57.760 --> 00:35:00.860 the salience network has the insula, which is 00:35:00.860 --> 00:35:05.900 right in here, very lateral, and then the anterior 00:35:05.900 --> 00:35:08.639 cingulate cortex, which is part of the medial 00:35:08.639 --> 00:35:11.760 prefrontal cortex. It's medial, so it's not as 00:35:11.760 --> 00:35:15.179 lateral. But these are the major hubs for the 00:35:15.179 --> 00:35:18.659 salience network. That paper found that connections 00:35:18.659 --> 00:35:22.219 to here were stronger. That's because of the 00:35:22.219 --> 00:35:25.480 diffusion, I think. I don't know if the paper 00:35:25.480 --> 00:35:30.059 highlighted that but whenever there's diffusion, 00:35:30.280 --> 00:35:33.519 there's just chaos versus the normal, the typical 00:35:33.519 --> 00:35:36.519 developed that didn't have these stronger connections 00:35:36.519 --> 00:35:40.960 to this sensory motor area. What if you could 00:35:40.960 --> 00:35:44.260 catch that and then provide some sort of intervention 00:35:44.260 --> 00:35:48.360 to help the living organism, the autistic phenyl 00:35:48.360 --> 00:35:54.920 child, to not bias so much to the inside? That's 00:35:54.920 --> 00:35:59.960 a conflict though, because how much the autistic 00:35:59.960 --> 00:36:04.159 phenotype gets out of being comfortable within 00:36:04.159 --> 00:36:08.139 is massive for learning. It's just the social 00:36:08.139 --> 00:36:11.820 norms kind of make this more complicated than 00:36:11.820 --> 00:36:15.340 what they are, what they should be. The autistic 00:36:15.340 --> 00:36:18.780 phenotype can learn at such accelerated rates 00:36:18.780 --> 00:36:22.260 because of how much these neural connections, 00:36:22.280 --> 00:36:27.760 these wires, biases us to the inside which is 00:36:27.760 --> 00:36:32.420 fine so serotonin's role with the sensory map 00:36:32.420 --> 00:36:36.420 we'll also do before we wrap up we'll also do 00:36:36.420 --> 00:36:43.840 an episode about serotonin's role versus t3 thyroxine 00:36:43.840 --> 00:36:49.079 t3 during this same epoch here has massive rows 00:36:49.079 --> 00:36:53.579 with specific cells It's underrated and unknown 00:36:53.579 --> 00:36:57.159 as well. This is all very fascinating because 00:36:57.159 --> 00:37:01.860 they're both from aromatic amino acids that absorb 00:37:01.860 --> 00:37:06.480 specific wavelengths of light. So, serotonin 00:37:06.480 --> 00:37:10.000 development in the sensory map. Diffusion versus 00:37:10.000 --> 00:37:12.320 refinement. Pruning.