MORE ON THE ipRGCs of the retina and SCN. Someday if someone funds my research, autism might be the first topic I’d suggest we study. Why?
Melanin seems to be important for migration of neurons in all mammals. I told you that in the recent blogs around melanin and metastasis. And this idea clued me long ago in that I might be able to explain autism because of my unique perspective on melanocyte migration and how it links to melanopsin regeneration.
Implications of a lack melanin pigment in mothers and fathers and what this might mean to their germ lines that become a child? Here is one of my kids above.
Today’s lesson is going to come from kitty. Most of you know I love cats. My favorite cat has always been the Siamese cat. My first cat was one and my current cat (above) is a Siamese. You might not know why I am fond of Siamese cats but you will soon. They taught me a lot about melanin when I was a boy in New York City.
CATS & HUMANS WHO ARE ALBINOS HAVE A MELANOPSIN LESSON TO TEACH
Most albino human beings and albino cats lacking retinal pigment in the RPE have observable nystagmus and many exhibit strabismus. The optic chiasm (pic above) of albino mammals including human beings and cats shows that almost all their retinal ganglion cells cross at the optic chiasm with few uncrossed optic fibers. This shows you there is a problem with morphology in mammals neurulation patterns. Something has to be behind this misrouting behavior. My bet is a lack of melanin allows the stickier deuterium isotope to affect cell migration during neurulation of the mammalin brain due to the kinetic isotope effect of deuterium on hydrogen in cells. One D controls 96 atoms of H+ (pic below). I think the massive increase of atomic weight and the kinetic isotope effect are critical in the misrouting behavior of neurons and this has dramatic effects on organization of the visual system of mammals. There are details about mammalian embryology that have lead me to this conclusion. I think it might be behind what causes autism, as well. A lack of melanin in the parents and their germ line cells maybe the precipatating event that begins this cascade of events on. I believe this idea is tied to autism because the effect is quite heterogenous in presentation, hence why they call autism a spectrum of disorders.
In 1965, C.L. Sheridan noticed that retinal ganglion cells originating in temporal retina of albino rats did not function well, hypothesizing that albino rats have fewer uncrossed, non-decussating optic fibers. R.D. Lund anatomically verified that albino rats have fewer non-decussating optic fibers compared to pigmented rats. For several years the abnormality of reduced non-decussating optic fibers at the optic chiasm in albinos was thought to be limited to rats and rabbits. Guillery reported atypical visual system organization in Siamese cats, but the association with albinism was not identified.
CIRCADIAN BIOLOGY ENTERS THE FRAY OF MY KITTY STORY
The mammalian SCN is controlled by light and temperature and by the ipRGC of melanopsin. I told you that a long time ago in the Cold Thermogenesis #6 blog. What else didn’t I mention back then?
In 1971, Creel initially published the connection between Siamese cats and albinism, and hypothesis that reduced non-decussating optic fibers likely is a “highly general transspecies phenomenon in albino mammals”. Siamese cats all have blue eyes and blue eyes = less melanin in the iris. Siamese cats, Himalayan mice, rats, and rabbits all express a mutation that is a temperature-sensitive pigmentation defect, that is, allowing pigment to show up only on the cold parts of the body.
This is why their coats are so grey and white (my kitty above). Moreover, their retinae lack pigment too. Many human infants are born with blue eyes because their brains are devoid of melanin because humans brains are born into life in an immature state. That is the case for human blue eyes, but what about the cats? Why do Siamese cats have blue eyes almost all time? It is not just their iris that has reduced melanin. Here we see the interplay of UV light and cold and begin to understand why this link is present from an evolutionary standpoint. Wide band gapped semiconductors can make the same light endogenously from atoms doped to proteins or via cooling environmental temperatures. I believe this is the basis of where the mammalian dive reflex comes from. Most humans who live at high latitudes where it is colder also tend to have blue eyes and blonde hair. The link is unmistakable when you realize it.
Cooling is usually occurs at surfaces in mammals (eccrine sweat glands) and most of their surface has arterioles loaded with higher levels of deuterium that act a Bose Einstein condensate because of deuterium unique nuclear spin. This makes their surface something important. It is called a topological insulator. Mammals interiors are filled with fermions = electrons and H+ ions. They follow Dirac fermion statistics. Here we see a physical difference manifesting in mammals for some reason.
Is there a trade off for mammals who live in colder environments? Yes there is. what is it?
They have less visual and non visual photoreceptors in their sensory organs.
Is this true in human mammals too, Uncle Jack? YEP.
Note when humans have normal pigmentation in the eye (RPE) tend to have optimized neuro-opthalmological migration in their visual system as well. It appears melanin is a beacon for proper migration of neurons in the eye to deeper brain structures in humans. This is critical in the eye because of the location of the SCN to the RPE. The SCN controls the eye clock, circadian rhythms, and the pupillary response in mammals to bright light. It also affects their behavior. This is markedly changed in autistic kids.
In humans with pigmented retinae, retinal blood vessels spare the foveal area. In albino human retinae, blood vessels intrude into foveal area. Pigmented human retina exhibit an avascular zone surrounding the fovea. Albinos do not exhibit this arrangement. They have blood vessel encroach into their fovea. Humans with destroyed RPE from diseases like diabetes get the very same neovascularization of the fovea. This ruins their central vision over time.
This is a big clue for what decentralized clinicians should be looking for in human’s with autism. If a lack of melanin is part of the pathophysiology of this disorder than we should see some subtle changes in OCT and their arteriole beds in the diencephalic derivative of the brain if we look for it, if I am correct. I think a lack of melanin pigment initiates atavistic expression in autistic kids of the central and peripheral nervous system. This lack of POMC or POMC translation leads to alterations in the melanopsin system that ruins normal neural migration.
The phenomenon is called atavism—this is the reappearance of a trait that had been lost during evolution before in the same species. In autism many of these kids cannot talk or interact with their species. We know our nearest cousins cannot speak either. We also know that early primates were loners and that social networking became a big trait later on in evolutionary history of the primate. This is another throw back behavior seen in autism that would have been seen in transitional chimps on their way to us. This change would not be found in our DNA either. Our genes do not determine who we are, but with atavism, they can sometimes serve as reminders of our evolutionary past. Functionally this is what autism in humans looks like to me from my current perspective. Another big clue for my hypothesis is found in the embryology of the visual and auditory systems of mammals.
MELANIN IS ALSO A TIME CRYSTAL FOR EMBRYOGENESIS IN MAMMALS
Embryonic progression in albino mammals’ visual and auditory systems seem to also take a step back in evolutionary time and it seems this program is initiated by lack of melanin pigment. Non albino animals do not exhibit this altered migratory pattern. Abnormalities of optic chiasmic misrouting in albino mammals is a developmental field defect that is seen normally in preceding phylogeny. Complete crossing of optic neurons at the chiasm is a normal developmental event in vertebrates prior to mammals. This reinforces my beliefs that atavism is a central problem in understanding modern autism.
The presence of melanin pigment in the embryonic retina is the signal that initiates retinal ganglion cell pathway routing from the eye to the SCN and from the SCN deep into the brain. Insufficient coding for retinal pigment launches an earlier, more stable genetic package directing a different targeting of optic neurons and this results in autism.
Genetic makeup includes preserved earlier evolutionary features. Charles Darwin popularized atavism in the 1860s as the term for reappearance of ancestral characteristics in future generations.
Today we know that vision and hearing evolved together dating back to the PaxB gene, which is a single gene controlling eye and precursors to hearing (mechanoreceptors) in box jellyfish. This occurred before independent Pax 2 and Pax 6 genes showed up in primates much later. There are evolutionary connections between eyes and mechanoreceptors of the inner ear to the extent that during evolution are linked to melanin generation in those sense organs. I told you earlier in the series melanin was the favored semiconductor of all mammals post KT event. This story fits this narrative as well. If POMC/melanin is absent for any reason, it appears human neuroplastiticty allows sensory cells to shift their sensory modalities to an older phylogeny experienced in evolutionary history. Why is this a big deal? The melanopsin phylogeny predates even primate evolution in time.
I think this happens in modern humans because of a loss of information and energy transformation in the embryo due to a lack of POMC or POMC translation in the parents cells and their germ lines that create their child. I think this is what autism is at its core. It is lack of POMC that has huge implications for the neurulation of the diencephalon in humans and its really old relationship to melanopsin biology.
BACK TO THE CATS
What happens when cats lack melanin in their eyes? Do they exhibit traits that mimic human autism? They exhibit fewer photoreceptors, they have foveal/area centralis hypoplasia, & exhibit misrouting of the temporal retinal ganglion cells, while having a variation of geniculate terminations, and most importantly they develop vascular intrusion into foveal area. They also exhibit abnormal cortical projections, and fewer cones in macular area. Lacking pigment in the cat leads to some major migration problems in the adult form. It seems albino kitties and Siamese cats have a lot in common with autism.
The animal model closest to organization of primate visual system studied the most is the albino cat. Albino cats have observable nystagmus, and many have strabismus. Figure 1 above pictures the optic chiasm of an OCA1 albino cat shows almost all retinal ganglion cells (RGCs) cross at the chiasm.
Not all of them do and the ones that do not cross tend to innervate areas they should not be in. The non visual photoreceptor associated with these RGCs is melanopsin. The number of binocular cells was found to be reduced in visual cortical areas of Brodman numbered 17, 18, and 19 in Siamese cats and albino cats. This impairs their stereovision. So these cats do not have great vision, but this is because they are adapted to colder environments with more blue light and less UV light. Their SCN periodicity can be retuned by cold weather. The trade off for their lack of melanin is altered neural migration in their brains.
This surface temperature thing is a big deal in mammals because our SCN changes its periodicity to temperature and light. I believe this explains why autistic kids do not like temperature changes or being touched. (another sensory processing delay). I have a sense why this happens in autistic kids because these changes are seen in cats as well who lack pigment. Autistic kids have a broken topological insulator in their skin, eyes, and circulatory system. I think they are exquisitely sensitive to the chiral pinch of deuterium in their blood and this creates a lot of endogenous light that overwhelms their system because they have poor melanin sheets within the basal levels of their skin. This allows too much deuterium to leach out of the circulatory system and into the substance of their subcutaneous tissues. These leaching of deuterium than alters non visual photoreceptors in that location.
There is some rather unique things to know about this situation. Evolution seems very fond of the SCN melanopsin connections I mentioned in QE #44. Why? Melanopsin retinal ganglion cells are always completely crossed or bilaterally projected into suprachiasmatic nuclei above the optic chiasm and these projections are not affected by albinism in any mammals. Interesting don’t you think?
I think this goes back to where melanopsin came from phylogenetically. It came from our fish amphibian origins 380 million years ago. Phylogenetically older connections are less abnormal in albino mammals by exhibiting a bilateral suprachiasmatic projection pathway to the SCN. These tracts appear to be unaffected in albinos. This tells me this system is highly protected by evolution because of how important it is to be able to simulate the physics of your environment to be highly adaptable. This also explains another peculiarity about the melanopsin system.
Melanopsin regeneratiion acts largely independently of the visual cycle. This tells me the melanopsin system has old roots in evolution and evolution has specifically made sure it did not co evolve similar mechanisms with the rod and cone system of the eye. Melanopsin neurons also control pupillary size with the autonomic nervous fibers of the third cranial nerve.
When this system is disrupted we get mammals that are not adaptable at all. This defines modern humans who are on the autism spectrum. Most children with autism have trouble sleeping, which may exacerbate other challenges associated with the condition. Sleep problems hint at disruptions in the circadian clock, a cellular timer that keeps cells in sync with the day-night cycle. Vitamin A disruption causes sleep disorders.
I have a sense that we will find out in the future that autistic children have wiring defects in their chiasms and in their sensory relay pathways because of a broken Vitamin A cycle in the melanopsin system along with a lack of melanin and POMC activity in the germ cells. This Vitamin A problem will lead to science realizing these kids all have altered melanopsin regeneration pathways compared to humans that do not have this deficit. I believe the melanopsin system has its own regeneration system because it is VITAL to accurate time crystal managment of the circadian mechanism you saw in the last blog. The SCN simulates the physics of our environment to program our metabolism from these light signals. This is broken in autism.
LACK OF POMC/MELANIN = ALTER MELANOPSIN REGENERATION = VITAMIN A PROBLEM
Vitamin A is necessary for normal embryonic development in humans, but its role in the adult brain is poorly understood by centralized science in 2023. Vitamin A derivatives, called retinoids, are involved in a complex signaling pathway that regulates gene expression and, in the central nervous system, controls neuronal differentiation and neural tube patterning.
There is another reason why I think this Vitamin A, melanin, melanopsin story is linked to autism. Most people know that the majority of melanin in the eye is in the RPE. What many however do not know is that the photosensitivity melanopsin requires a steady supply of cis-retinaldehyde, a type of retinoid. The primary source of this vitamin chromophore (328nm) in the vertebrate eye comes from a complex multistep enzymatic pathway, known as the retinoid or visual cycle (above). In this cycle by 11-cis retinaldehyde is regenerated from bleached all–trans originating in photoreceptor outer segments of rods. The critical elements of this pathway occur in the retinal pigment epithelium (RPE). Here is the problem. Since melanopsin is found in the more superficial layers of the retina, quite distant from the RPE, it would seem poorly placed to obtain cis-retinaldehyde from this RPE source. So how does melanopsin do it? Why does it have its own regeneration pathway separate from rods and cones?
Chromophore regeneration in rod photoreceptors relies solely on a tissue adjacent to the rod and cone layer of the retinal pigment epithelium. Cone photoreceptors rely both on the RPE and Müller glia, which traverse the entire depth of the retina to regenerate. Melanopsin doesn’t use either system.
In the mammalian photoptic retina light activates melanopsin to trigger a G protein cascade that causes membrane depolarization. The ipRGCs/melanopsin response is opposite to that seen in our rods and cones, which hyperpolarize, but resembles the actions of photoreceptors found in invertebrates like fruit flies and horseshoe crabs. This system exhibits atavism mentioned above. In humans, ipRGCs fire spikes. They are understood to use glutamate as their primary neurotransmitter; uniquely among RGCs, they also express a peptide neurotransmitter called PACAP (pituitary adenylate cyclase activating peptide).
Known influences of ipRGCs extend well beyond their direct targets. Examples are regulation of melatonin synthesis in the pineal gland and the development of synaptic plasticity in the hippocampus. I believe they drive synaptic plasticity in all of our brain’s circuits and this is why melanopsin is the most numerous opsin in humans.
Why do I mention this detail? Most people forgot human embryology of the brain and skin. They have forgotten that Vitamin A/retinoic acid have massive effects in the morphogenesis and growth of the neural tube. Not only will deuterium affect neural migration from the notochord, but the chemical signal governing it is likely also awry. Most of which can be explained by defective notochord signalling. This would cause neurulation defects from the thalamus to the adult hemispheres. This process is how humans create their hemispheres in the last trimester and postnatally. This set of circumstances fits the modern phenotype of autism based upon my knowledge of human brain embryology. I think the key problem in the autistic embryo is a problem of Vitamin A signaling being comingled in the eye, optic chiasm, hypothalamus, thalamus and eventually the neocortex in humans. This would create a wide spectrum phenotype in the adult human.
Modern humans are new phylogenetic creatures in evolution and we know that optic projections near chiasm projecting into hypothalamus antecede vertebrates evolution because they occurred in early chordates. Chordates first appeared on Earth 590 million years ago. Those are the animals that innovated melanopsin originally.
It appears that fact surprised Dr. Huberman and Dr. Berson based on what Huberman said in the Rubin podcast. It did not shock me because I knew mammals came from early chordates because of my time in the Museum of Natural History in New York. This is why it made sense to me why we had melanopsin in our brains. I was shocked to learn in 2014-2017 that we also have it all our blood vessels, skin, fat, and our outer inferior retina. Nature does not make mistakes.
This is my kitty today as I write this blog. She likes IR-A and UV-A light now. I have a sense all parents with autism need to learn a lot more about full spectrum sunlight and the key frequencies of IR-A light and the 380 nm light that controls the photorepair mechanisms in mammals. When they do, they will realize how to help fix the problem they created by their abuse of blue light and tech screens.
SUMMARY
When I was 8 was the first time I got a Siamese cat. I asked the lady at the museum why my cats eyes were different colors than other cats and she did not know the answer. She told me she’d find out and few weeks later I found out about melanin as an 8 year old kid. She told me all chordates had retinal pigments matching vertebrates. Humans were the latest version of vertebrates. That lesson would come in big later in my life. I never forgot about my kitty’s eyes. And that is why it never surprised me that the melanopsin chromophore showed up in human brain. My childhood was prepping me for a later discovery around this amazing protein. People with autism one day may thank Siamese cats for solving this enigma disorder for centralized science.
CITES
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2. Lund RC. Uncrossed visual pathways of hooded and albino rats. Science. 1965;149:1505-1507
3. Giolli RA, Guthrie MD. The primary optic projections in the rabbit: An experimental degeneration study. The Journal of Comparative Neurology. 1969;136:99-126
4. Guillery RW. An abnormal retinogeniculate projection in Siamese cats. Brain Research. 1969;14:739-741
5. Creel DJ. Visual system anomaly associated with albinism in the cat. Nature. 1971;231:465-466
6. Creel DJ. Differences of ipsilateral and contralateral visually evoked responses in cats: Strains compared. Journal of Comparative and Physiological Psychology. 1971;77:161-165
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8. Sanderson KJ. Retinogeniculate projections in the rabbits of the albino allelomorphic series1. The Journal of Comparative Neurology. 1975;159:15-27
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12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571178/
13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6601915/
14. https://www.cell.com/cell-reports/pdf/S2211-1247(18)31754-6.pdf