Brain development and Neoteny / Neuroscience

J Psychiatry Neurosci. 2011 Nov;36(6):412-21. doi: 10.1503/jpn.100138.

Can Asperger syndrome be distinguished from autism? An anatomic likelihood meta-analysis of MRI studies.

Yu KK1, Cheung C, Chua SE, McAlonan GM

Whereas grey matter differences in people with Asperger syndrome compared with controls are sparser than those reported in studies of people with autism, the distribution and direction of differences in each category are distinctive.

Abstract

In development, timing is of the utmost importance, and the timing of developmental processes often changes as organisms evolve. In human evolution, developmental retardation, or neoteny, has been proposed as a possible mechanism that contributed to the rise of many human-specific features, including an increase in brain size and the emergence of human-specific cognitive traits. We analyzed mRNA expression in the prefrontal cortex of humans, chimpanzees, and rhesus macaques to determine whether human-specific neotenic changes are present at the gene expression level. We show that the brain transcriptome (transcriptome includes all mRNA transcripts in the cell; it reflects the genes that are being actively expressed at any given time, with the exception of mRNA degradation phenomena such as transcriptional attenuation.) is dramatically remodeled during postnatal development and that developmental changes in the human brain are indeed delayed relative to other primates. This delay is not uniform across the human transcriptome but affects a specific subset of genes that play a potential role in neural development.

Conclusion

By comparing the gene expression profiles in human, chimpanzee, and rhesus macaque prefrontal cortices throughout postnatal development, we have found that there is no uniform shift in the developmental timing between humans and other primates. We find instead a significant excess of genes showing neotenic expression in humans. This result is in line with the neoteny hypothesis of human evolution (6) and provides insight into the possible functional role of neoteny in human brain development. Specifically, we show that at least in one of the 2 cortical regions studied, the neotenic shift is most pronounced at the time when humans approach sexual maturity, (body matures; brain does not) a process known to be delayed in humans relative to chimpanzees or other primates (6, 24). Furthermore, the neotenic shift particularly affects a group of genes preferentially expressed in gray matter. Intriguingly, the timing of the shift also corresponds to a period of substantial cortical reorganization characterized by a decrease in gray-matter volume, which is thought to be related to synaptic elimination (21, 25, 26). The developmental pace of changes in gray-matter volume has been associated with the development of cognitive skills among humans (e.g., linguistic skills) (27) as well as with the development of disorders (e.g., attention-deficit/hyperactivity disorder) (28).

Although the precise causes and consequences of the human neotenic shift remain unknown, together these observations suggest that ontogenetic timing differences between the human and the chimpanzee prefrontal cortex transcriptomes may reflect differences in sexual and cognitive maturation between the 2 species. According to this logic, delayed gray-matter maturation in the human prefrontal cortex may extend the period of neuronal plasticity associated with active learning, thus providing humans with additional time to acquire knowledge and skills.

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Things to think about:

Maturation of gray matter in the human prefrontal cortex is delayed by neotenic shifts. Developmental delay is neotenic. There is a “fuzzy boundary” (?) between too much / too little grey matter volume for the brain to function well; there also seem to be 2 types of brain organization: social navigation vs. factual and problem-solving. (See today’s Temple Grandin post.) These are probably not ‘separate’ paths, but are developmental stages. (Social is juvenile; factual is adult.)

The gray matter volume in any specific human brain may vary between mature and neotenic states. Humans vary in degrees of neoteny. It might be more accurate to dump “Autism Spectrum” for an inclusive classification “The Neoteny Spectrum” which includes all contemporary homo sapiens.

How do we know which human brains (volume of grey matter) are mature and which are neotenic? What volume of grey matter is the reference for maturity vs. neoteny? We can begin with behavior.

Some changes in grey matter volume occur during puberty: therefore it would be useful to compare the pre-puberty and post-puberty states of grey matter in individuals, especially those diagnosed with a “brain disorder” in early childhood. Mixing data from before and after stages of brain reorganization may be completely misleading do to variations in timing.

Grey matter differences in individuals reflects maturity vs. neoteny (a spectrum of rates of development) and not fundamental developmental disability; if one is ONLY interested in “The Social Brain,” and designates this juvenile stage of development as the ONLY legitimate human brain, then the “problem” of Asperger’s is the product of inattentional blindness and ignorance. Bad science!

CASE IN POINT: It is said that Asperger’s have “less than normal” volumes of gray matter, but if this conclusion has been derived from pre-puberty testing, then it is entirely possible that Asperger children, in terms of specific brain development, (intellect, language, concrete – visual thinking, facts and problem-solving) simply MATURE FASTER – and gray matter volume is reduced to a more effective and efficient volume well before their peers.

Social brains are neotenic; the neurotypical neotenic brain never fully matures. Which means that the social orientation (obsession) of modern social humans is the product of extreme neoteny.   Neoteny is evident in a lack of logic, rationality, analytical thinking and effective problem-solving, which are absent in everyday life and most seriously, in our political leaders.

“Juvenile” neotenic behavior is evident in the inability to recognize that facts and physical reality exist. Instead, emotions are paramount; self absorption is rampant, magical thinking prevails, action is missing, narcissitic orientation is “normal”, and “worship of” childlike celebrities is a substitute for adult models and personal development. Adult children never leave home but remain dependent on parental support. Violence is characteristic of juvenile males; violent behavior usually decreases as males age, but today “frivolous” violence is the perpetual activity of neotenic males and is encouraged by popular culture.

 

Cerebral Asymmetry / Asperger Brain Differences

Philosophical Transactions of the Royal Society / Biological sciences

The evolution and genetics of cerebral asymmetry

http://rstb.royalsocietypublishing.org/content/364/1519/867/

Michael C Corballis

Looking Back on Bipolar / Seasonal Transitions and Disruptions

See also related Circadian Rhythm posts –

I used to be bipolar; diagnosed long ago, before Asperger’s was a recognized “thing” (1994) and not considered applicable to females. Looking back, I think this was a mistake – the “bipolar” symptoms I experienced can logically be seen as evidence for “Asperger-ness” as a brain type that processes the environment in a distinct and even radically different way than the overwhelming majority of Modern Social Humans – neurotypicals. One notable problem for me, was and is, a response to seasonal change; lack of sunlight and outdoor activity in winter produce a direct physical effect: extreme restlessness (anxiety) and a longing for the world to “come back” – to revive, to be washed in sunlight and present a landscape wide open to movement. This is not an uncommon condition for many people! The experience can be grossly represented as  claustrophobia. Winter is a time, that once adjusted to, can be very productive; a time of internal focus, mental activity and concentration.

The transition into summer, while eagerly embraced, can be disruptive, unsettling, and “mind-blowing” – Where I live, it’s a long process; inter-leaving of days of increasing sunlight that fool fragile plant life into attempts to emerge, but which are discouraged by snow storms and overnight freezes. The energy gained by extended sunlight at high altitude (6,000-7,000 feet) hits a certain point – and suddenly, our tan and brown,  heavily dissected desert is GREEN. It’s “shocking” to the eye; strange and brief. The sagebrush steppe is covered in prickly shrubs and myriad bunch grasses, which  must reproduce in the short window of mid May through June, and then pack away their chlorophyll for another year, leaving only yellow leaves and seeds to be dispersed by the famous Wyoming wind.  A palette of rich yellows, pale earth, and dusty gray green returns; a much more interesting landscape for sunlight to change in appearance, from moment to moment, throughout the day and evening. A “light show” transforms our two-part landscape of land and sky – a daily cycle of color and shadow that passes into cool night.

I don’t know if this experience of reality is common to Asperger individuals; that is  – the direct influence of the environment on mood, emotion and energy. This responsiveness to the land is not exclusive to Asperger’s types.

This desert has no “social” uses; agriculture is futile. Few people can live here, and without resource extraction for “dollars” and importation of food, even fewer could, or would stay. There is something extremely luxurious about a landscape that can’t be “socialized” – unitized, divided, owned and exploited by human agriculture, trade, commerce – made useful or productive. There’s something extremely luxurious about a life that grows to fit this type of land. I was made for this place: finding it meant “letting go of things not meant for me.” The Bhudda.

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Original post about transitioning from summer into winter:

This is my 65th transition from summer into fall. Of course I don’t remember most of these changes. Fall is a bit of a drive-through season; the way we get to winter. It says so on the calendar: First Day of Fall, but for me it’s a long drawn out state of confusion, instability, moodiness: doom. What has disrupted my normal, careful, mostly peaceful days? Normal for me: my “writer’s routine” of coffee, computer and coming awake. Sometimes writing is easier while I’m still a bit stupefied by sleep.

Anticipation: that’s my experience of Fall, as if something momentous is about to happen, but it never does. One morning the garden plants have frozen, cells bursting; really physically dead; mush with frost rimming the remains. Light snow that melts quickly, the rocks damp and shiny, their colors deep and revealing.

It’s not that I don’t like winter, but some innocent intuitive organ believes that the earth is dying, and me with it. These experiences are so strong and consistent year after year, that I’m sure that being bipolar has something to do with ancient humans -tropical creatures who pushed too far north for their mental health. People whose brains and bodies were extensions of the seasons: work like mad in Spring and Summer and semi-hibernate in winter. Expend the least energy possible obtaining food and water; curl up like most of nature and sleep and dream an alternate existence filled with giants, heroes and mortal powers.

 

 

 

How much talent is wasted because society doesn’t like the package it comes in?

images

In the day-to-day experience of an Asperger child, moments of peace are rare. Whatever you are thinking or doing, someone, either a parent or teacher, or maybe another child, will interrupt you, to ask that you participate in another activity, such as playing a game with a group of children. If you don’t respond, or you resist their prodding, or if you state clear and repeated rejections, sweet tones of persuasion turn to harsh words and insults. An adult will express personal disappointment in your reluctance to obey and will continue to pressure you, as if whatever you are occupied with is not only unimportant, but that preferring to be alone means that you are depressed or unhappy, and that joining the group will cheer you up, which isn’t true. If you persist in thinking that what you are reading, or drawing or building is more interesting than what the other children are doing, you are apt to be yelled at and physically relocated like a disobedient dog. When this happens, the waves of anger that were hidden beneath the adult’s nice words hit like a shock wave. The effect is visceral and devastating.

It is said that Asperger children can’t infer what is going on in another person’s mind, but the message is clear: people, especially adults, will only like you if you agree with their statements, however false or petty, and obey their instructions, and not when you get around to it, but now! Your willingness to conform must be expressed in signs made by body, face and words. It’s not enough that you act promptly as they wish, but a child or grown person must show his or her deference to a person of superior status. It soon becomes evident that no social interaction is neutral: this ‘status thing’ is the point of social interaction. What is often referred to as ‘busy work’ takes place in schools and workplaces day in and day out, simply to prove that a certain category of human is The Boss. Obedience is a social necessity because it demonstrates that a child or adult will subordinate its happiness and well-being to the group. Rules and instructions are often designed to insult and confuse people, to challenge their morality or sense of fair play and for no other purpose than to test their willingness to shed their individual humanity and to become a tool in the construction and maintenance of the Social Pyramid – to blindly believe that The Boss Knows Best.

The Asperger brain simply doesn’t understand this social compulsion, not because we are dumb, defective, dangerous or disabled, but because inequality of status is alien to our instinct for fair play, justice and reason. For us the world is integrated, coherent, and dynamic and is a continuous expression of Nature’s truths: the universe as described by social concepts is a sad and dreary spectacle of human arrogance and ignorance; a childish place maintained by violence, lies and deprivation; established by the denial of human worth and by denial of basic needs: water, food, shelter to those who “don’t count”. Those who are on top must imprison millions of human beings on the low levels of the Social Pyramid in order to feel good.

The Asperger outlook on people is nearly the opposite: people are just people. Instead of a steep pyramid on which millions of human beings struggle for dominance, we have a visual landscape of reality in our minds. Each human, animal, plant, and object in the landscape is distinct and “counts” because our perception of the environment is concrete: humans live with their feet on the ground, not above or below, but as equal agents of Nature. Cooperation, not competition for status, makes sense to us. Let each human fulfill his or her gifts; don’t waste resources. How much talent is wasted because Society doesn’t like the package it comes in?

Brow Ridge unrelated to cognitive development

Comparing Frontal Cranial Profiles in Archaic and Modern Homo by Morphometric Analysis

FRED BOOKSTEIN et al

There is an 8-page pdf for this paper, but once again I can’t get the URL to connect.

Brain_directions__planes_-_smallINTRO: Archaic and modern human frontal bones are known to be quite distinct externally, by both conventional visual and metric evaluation. Internally this area of the skull has been considerably less well-studied. Here we present results from a comparison of interior, as well as exterior, frontal bone profiles from CT scans of five mid-Pleistocene and Neanderthal crania and 16 modern humans. Analysis was by a new morphometric method, Procrustes analysis of semi-landmarks, that permits the statistical comparison of curves between landmarks. As expected, we found substantial external differences between archaic and modern samples, differences that are mainly confined to the region around the brow ridge. However, in the inner median-sagittal profile, the shape remained remarkably stable over all 21 specimens. This implies that no significant alteration in this region has taken place over a period of a half-million years or more of evolution, even as considerable external change occurred within the hominid clade spanning several species. This confirms that the forms of the inner and outer aspects of the human frontal bone are determined by entirely independent factors, and further indicates unexpected stability in anterior brain morphology over the period during which modern human cognitive capacities emerged.

(New Anat): 257:217–224, 1999. 1999 Wiley-Liss, Inc.

External changes (such as the brow ridge) ARE NOT LINKED morphologically to the frontal brain, which has been stable for 500,000 years of  cognitive development.

Basic CMYK

 

Neurotypical Perception Defects / Inferred Images, Social Filters

Humans rely more on ‘inferred’ visual objects than ‘real’ ones

May 16, 2017
Summary:
Humans treat ‘inferred’ visual objects generated by the brain as more reliable than external images from the real world, according to new research.
“In such situations with the blind spot, the brain ‘fills in’ the missing information from its surroundings, resulting in no apparent difference in what we see,” says senior author Professor Peter König, from the University of Osnabrück’s Institute of Cognitive Science. “While this fill-in is normally accurate enough, it is mostly unreliable because no actual information from the real world ever reaches the brain. We wanted to find out if we typically handle this filled-in information differently to real, direct sensory information, or whether we treat it as equal.”

Visual thinkers are all too aware of this reality deficit in the “typical” perception of reality; I can’t say that the mechanism described here is the “cause” of discrepancies between “typical” perception and the greatly enhanced perception of visually-oriented brains, but it does point out that the typical human brain has evolved “short cuts” that result in varying accuracy in the  perception of the environment. This deficit, combined with de facto “magical-social” thinking has dire consequences for survival.

Links:

Article in Science Daily: https://sciencedaily.com/releases/2017/05/170516080752.htm

Original Paper with figures, charts: 10.7554/eLife.21761

Posts on inattentional blindness: https://aspergerhuman.wordpress.com/2015/12/04/visual-thinking-inattentional-blindness/

https://aspergerhuman.wordpress.com/2015/12/04/inattentional-blindness-why-the-u-s-gets-sucker-punched-by-terrorists/

Immune System Introgressions / Neandertal, Denisovan HLA alleles


Neanderthal, State Museum, Halle, Germany

Denisovan admix today: Low – Black / High – Red

 

The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans

Laurent Abi-Rached,1 (see original paper for list of authors)

Abstract

Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic HLA class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.

Example: Includes similar graphics for Neanderthal and Denisovan HLA alleles

Fig. 3 Effect of adaptive introgression of Neandertal HLA class I alleles on modern human populations. (A) All six Neandertal HLA-A, -B and -C alleles are identical to modern HLA class I alleles…

 

Neanderthal- H. Sapiens Ancestral Gene EXCHANGE

Neanderthal inheritance helped humans adapt to life outside of Africa

Phys.org / November 10, 2016

Read more at: https://phys.org/news/2016-11-neanderthal-inheritance-humans-life-africa.html#jCp

Excerpt: All told, the new study identifies 126 different places in the genome where genes inherited from those archaic humans remain at unusually high frequency in the genomes of modern humans around the world. We owe our long-lost hominid relatives for various traits, and especially those related to our immune systems and skin, the evidence shows.

“Our work shows that hybridization was not just some curious side note to human history, but had important consequences and contributed to our ancestors’ ability to adapt to different environments as they dispersed throughout the world,” says Joshua Akey of University of Washington School of Medicine in Seattle.

While the vast majority of surviving Neanderthal and Denisovan sequences are found at relatively low frequencies (typically less than 5%), the new analyses turned up 126 places in our genomes where these archaic sequences exist at much higher frequencies, reaching up to about 65%. Seven of those regions were found in parts of the genome known to play a role in characteristics of our skin. Another 31 are involved in immunity.

“The ability to increase to such high population frequencies was most likely facilitated because these sequences were advantageous,” Akey explains. “In addition, many of the high-frequency sequences span genes involved in the immune system, which is a frequent target of adaptive evolution.”

Generally speaking, the genes humans got from Neanderthals or Denisovans are important for our interactions with the environment. The evidence suggests that hybridization with archaic humans as our ancient ancestors made their way out of Africa “was an efficient way for modern humans to quickly adapt to the new environments they were encountering.”

Reconstruction by Fabrio Fogliazza /

Neanderthals mated with modern humans much earlier than previously thought

February 17, 2016 https://phys.org/news/2016-02-neanderthals-modern-humans-earlier-previously.html#jCp