Cerebrum

The impact of the last snowflake

gettingwell4 4-5 stars Advanced knowledge, Beliefs, Cerebrum

Was the recent Swiss avalanche’s cause the last, triggering snowflake, or the billions of snowflakes before it?

There’s been a slight increase in the number of PNAS studies that included the “catastrophic” search word from October 2016 to mid-January 2018 compared to the January 2014 to mid-April 2015 period referenced in How well can catastrophes be predicted?.

What are the drivers?

Or is the main driver something else?

Non-CpG DNA methylation

gettingwell4 2-3 stars Required further work, Brain development, Cerebrum, Dopamine, Epigenetics, Glutamate, Hippocampus, Limbic system, Lower brain, Memory, Neurochemicals , , , ,

This 2017 Korean review compared and contrasted CpG and non-CpG DNA methylation:

“Non-CpG methylation is restricted to specific cell types, such as pluripotent stem cells, oocytes, neurons, and glial cells. Accumulation of methylation at non-CpG sites and CpG sites in neurons seems to be involved in development and disease etiology.

Non-CpG methylation is established during postnatal development of the hippocampus and its levels increase over time. Similarly, non-CpG methylation is scarcely detected in human fetal frontal cortex, but is dramatically increased in later life. This increase in non-CpG methylation occurs simultaneously with synaptic development and increases in synaptic density.

In contrast, CpG methylation occurs during early development and does not increase over time.

Neurons have considerably higher levels of non-CpG methylation than glial cells. The human male ES [embryonic stem] cell line (H1) is more highly methylated than the female ES cell line (H9).

Among the different types of non-CpG methylation (CpA [adenosine], CpT [thymine], and CpC [another cytosine]), methylation is most common at CpA sites. For instance, in human iPS [induced pluripotent stem] cells, 5mCs are found in approximately 68.31%, 7.81%, 1.99%, and 1.05% of CpG, CpA, CpT, and CpC sites, respectively.”

The reviewers’ referenced statement:

“CpG methylation occurs during early development and does not increase over time.”

was presented outside of its context. The 2013 cited source’s statement was restricted to “selected loci” in the rodent hippocampus:

“Consistent with a recent study of the cortex, time-course analyses revealed that CpH [non-CpG] methylation at the selected loci was established during postnatal development of the hippocampus and was then present throughout life, whereas CpG methylation was established during early development.”

Epigenetic study methodologies improved in 2017 had more information on CpA methylation.

http://www.mdpi.com/2073-4425/8/6/148/htm “CpG and Non-CpG Methylation in Epigenetic Gene Regulation and Brain Function”

Can researchers make a difference in their fields?

gettingwell4 0-1 star Wasted resources, Cerebrum, Epigenetics, Immune system, Limbic system, Lower brain, Memory , , ,

The purpose and finding of this 2017 UK meta-analysis of human epigenetics and cognitive abilities was:

“A meta-analysis of the relationship between blood-based DNA methylation and cognitive function.

We identified [two] methylation sites that are linked to an aspect of executive function and global cognitive ability. The latter finding relied on a relatively crude cognitive test..which is commonly used to identify individuals at risk of dementia.

One of the two CpG sites identified was under modest genetic control..there are relatively modest methylation signatures for cognitive function.”

The review’s stated limitations included:

“It is, of course, possible that a reliable blood-based epigenetic marker of cognitive function may be several degrees of separation away from the biological processes that drive cognitive skills.

There are additional limitations of this study:

  • A varying number of participants with cognitive data available for each test;
  • Heterogeneity in relation to the ethnicity and geographical location of the participants across cohorts; and
  • Relating a blood-based methylation signature to a brain-based outcome.

A 6-year window [between ages 70 and 76] is possibly too narrow to observe substantial changes in the CpG levels.”

All of these limitations were known before the meta-analysis was planned and performed. Other “possible” limitations already known by the 47 coauthors include those from Genetic statistics don’t necessarily predict the effects of an individual’s genes.

The paper referenced studies to justify the efforts, such as one (cited twice) coauthored by the lead author of A problematic study of DNA methylation in frontal cortex development and schizophrenia:

“Epigenome-wide studies of other brain-related outcomes, such as schizophrenia, have identified putative blood-based methylation signatures.”

Was this weak-sauce meta-analysis done just to plump up 47 CVs? Why can’t researchers investigate conditions that could make a difference in their fields?

Was this meta-analysis done mainly because the funding was available? I’ve heard that the primary reason there are papers like the doubly-cited one above is that the US NIMH funds few other types of research outside of their biomarker dogma.

The opportunity costs of this genre of research are staggering. Were there no more productive topics that these 47 scientists could have investigated?

Here are a few more-promising research areas where epigenetic effects can be observed in human behavior and physiology:

I hope that the researchers value their professions enough to make a difference with these or other areas of their expertise. And that sponsors won’t thwart researchers’ desires for difference-making science by putting them into endless funding queues.

https://www.nature.com/articles/s41380-017-0008-y “Meta-analysis of epigenome-wide association studies of cognitive abilities”

Science and technology hijacked by woo

gettingwell4 < 0 Detracted from science, Beliefs, Cerebrum

I’m an avid reader of science articles, abstracts, studies, and reviews. I tried a free subscription to Singularity Hub for a few weeks last month because it seemed to be a suitable source of articles on both science and technology.

I unsubscribed after being disappointed by aspects of science and technology hijacked almost on a daily basis into the realm of woo. Discovering scientific truths and realizing technologies is inspiring enough to stand on its own. It’s sufficiently interesting to publish well-written articles on the process and results.

I was dismayed that the website didn’t host a feedback mechanism for the authors’ articles. We shield ourselves from information incongruent with our beliefs. It’s a problem when a publisher of science and technology articles similarly disallows non-confirming evidence as a matter of policy.

An article may or may not advance knowledge of the subject, and Singularity Hub enables author hubris in presenting their views as the final word on the subject. Directing readers elsewhere for discussion is self-defeating in that every publisher’s goals include keeping visitors on their website as long as possible.

Here’s my feedback on two articles that inappropriately bent reality.

Regarding What Is It That Makes Humans Unique?:

“This trait [symbolic abstract thinking] not only gives us the ability to communicate symbolically, it also allows us to think symbolically, by allowing us to represent all kinds of symbols (including physical and social relationships) in our minds, independent of their presence in the physical world. As a result, internal associations of novel kinds become possible.”

Why limit discussion of our capability for symbolic representations? Other features to explore are:

  1. Aren’t beliefs also products of symbolic abstract thinking?
  2. What attributes of human behavior provide evidence for hopes and beliefs as symbolic representations?
  3. What’s the evolved functional significance that benefits humans of using symbolic abstract thinking to develop hopes and beliefs?

“Our revolutionary traits stand out even more when we take a cosmic perspective. We are not only in the universe, but the universe is also within us. Our brains, as an extension of the universe, are now being used to understand themselves.”

This article should be written well enough to inspire without resorting to unevidenced assertions about revolutions, the cosmos, and the timing of brain functionality.

“Some of us possess higher consciousness than others. The question that we now have to ask ourselves is, how do we cultivate higher consciousness, structural building, and symbolic abstract thinking among the masses?”

What’s the purpose of steering an evolution topic into elitism?

How a Machine That Can Make Anything Would Change Everything received >53,000 views compared with <5,000 views of the above article. This was an indicator that readers of Singularity Hub are relatively more interested in the possible implications of future technology than those of our past biological evolution. Why?

“If nanofabricators are ever built, the systems and structure of the world as we know them were built to solve a problem that will no longer exist.”

We are to believe that we’ll soon have the worldwide solution to problems in food supply, energy supply, medicine availability, income, knowledge – all that’s needed for survival? Should we develop hopes that technology will be our all-providing savior? Hope sells, without a doubt, but why would Singularity Hub mix that in with science?

This article reminded me of the chip-in-the-brain article referenced in Differing approaches to a life wasted on beliefs. Both articles seemingly appealed to future prospects, but the hope aspect showed that the appeals were actually reactions to the past.

If we individually address the impacts of past threats to survival – that include beliefs about future survival – each of us can break out of these self-reinforcing, life-wasting loops. Otherwise, an individual’s thoughts, feelings, and behavior are stuck in reacting to their history, with hopes and beliefs being among the many symptoms.

“Human history will be forever divided in two. We may well be living in the Dark Age before this great dawn. Or it may never happen. But James Burke, just as he did over forty years ago, has faith.”

Is it inspiring that the person mentioned has had a forty-year career of selling beliefs in technology?

Yes, future technologies have promise. Authors can write articles that provide developments without soiling the promise with woo.

This post has somehow become a target for spammers, and I’ve disabled comments. Readers can comment on other posts and indicate that they want their comment to apply here, and I’ll re-enable comments.

The pain societies instill into children

gettingwell4 2-3 stars Required further work, Beliefs, Cerebrum, Epigenetics, Memory, Primal Therapy, Stress , , , , ,

The human subjects of this 2017 Swiss study had previously been intentionally traumatized by Swiss society:

“Swiss former indentured child laborers (Verdingkinder) were removed as children from their families by the authorities due to different reasons (poverty, being born out of wedlock) and were placed to live and work on farms. This was a practice applied until the 1950s and many of the Verdingkinder were subjected to childhood trauma and neglect during the indentured labor.

DNA methylation modifications indicated experiment-wide significant associations with the following complex posttraumatic symptom domains: dissociation, tension reduction behavior and dysfunctional sexual behavior.”


https://bmcresnotes.biomedcentral.com/articles/10.1186/s13104-017-3082-y “A pilot investigation on DNA methylation modifications associated with complex posttraumatic symptoms in elderly traumatized in childhood”

Imagine being taken away from your family during early childhood for no other reason than your parents weren’t married.

Consider just a few of the painful feelings such a child had to deal with then and ever since:

  • I’m unloved.
  • Alone.
  • No one can help me.

Imagine some of the ways a child had to adapt during their formative years because of this undeserved punishment:

  • How fulfilling it would be to believe that they were loved, even by someone they couldn’t see, touch, or hear.
  • How fulfilling it would be to get attention from someone, anyone.
  • How a child became conditioned to do things by themself without asking for help.

The study described a minute set of measurements of the subjects’ traumatic experiences and their consequential symptoms. The researchers tried to group this tiny sample of the subjects’ symptoms into a new invented category.

Another example was provided in Is IQ an adequate measure of the quality of a young man’s life?:

“During this time period [between 1955 and 1990], because private adoptions were prohibited by Swedish law, children were taken into institutional care by the municipalities shortly after birth and adopted at a median age of 6 mo, with very few children adopted after 12 mo of age.”

Swedish society deemed local institutional care the initial destination for disenfranchised infants, regardless of whether suitable families were willing and able to adopt the infants. What happened to infants who weren’t adopted by age 1?

Did Swedish society really need any further research to know that an adoptive family’s care would be better for a child than living in an institution?

It’s hard to recognize when our own thoughts, feelings, and behavior provide evidence of childhood pain that’s still with us.

Let’s not hope and believe that the societies we live in will resolve adverse effects of childhood trauma its members caused. Other people may guide us, but each of us has to individually get our life back:

“What is the point of life if we cannot feel and love others? Without feeling, life becomes empty and sterile.

It, above all, loses its meaning.“

Every society has its horror stories. People who have reached some degree of honesty about their early lives and concomitant empathy for others can document these terrible circumstances and events.

Have traumatic effects on children from societal policies ceased?

Epigenetic study methodologies improved in 2017

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Beliefs, Brain development, Cerebrum, Epigenetics, Limbic system, Stress , , , , ,

Let’s start out 2018 paying more attention to advancements in science that provide sound empirical data and methodology. Let’s ignore and de-emphasize studies and reviews that aren’t much more than beliefs couched in models and memes, whatever their presumed authority.

Let sponsors direct researchers to focus on ultimate causes of diseases. Let’s put research of treatments affecting causes ahead of those that only address symptoms.

Here are two areas of epigenetic research that improved in 2017.

Improved methodologies enabled DNA methylation studies of adenine, one of the four bases of DNA, to advance, such as this 2017 Wisconsin/Minnesota study N6-methyladenine is an epigenetic marker of mammalian early life stress:

“6 mA is present in the mammalian brain, is altered within the Htr2a gene promoter by early life stress and biological sex, and increased 6 mA is associated with gene repression. These data suggest that methylation of adenosine within mammalian DNA may be used as an additional epigenetic biomarker for investigating the development of stress-induced neuropathology.”

Most DNA methylation research is performed on the cytosine and guanine bases.

Other examples of improved methodologies were discussed in this 2017 Japanese study Genome-wide identification of inter-individually variable DNA methylation sites improves the efficacy of epigenetic association studies:

“A strategy focusing on CpG sites with high DNA methylation level variability may attain an improved efficacy..estimated to be 3.7-fold higher than that of the most frequently used strategy.

With ~90% coverage of human CpGs, whole-genome bisulfite sequencing (WGBS) provides the highest coverage among the currently available DNAm [DNA methylation] profiling technologies. However, because of its high cost, it is presently infeasible to apply WGBS to large-scale EWASs [epigenome-wide association studies], which require DNAm profiling of hundreds or thousands of subjects. Therefore, microarrays and targeted bisulfite sequencing are currently practicable for large-scale EWASs and thus, effective strategies to select target regions are essentially needed to improve the efficacy of epigenetic association studies.

DNAm levels measured with microarrays are invariable for most CpG sites in the study populations. As invariable DNAm signatures cannot be associated with exposures, intermediate phenotypes, or diseases, current designs of probe sets are inefficient for blood-based EWASs.”

How to cure the ultimate causes of migraines?

gettingwell4 5+ stars Premium, Amygdala, Beliefs, Brain development, Brainstem, Cerebrum, Cortisol, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Lower brain, Memory, Neurochemicals, Oxytocin, Serotonin, Stress , , , , , , ,

Most of the spam I get on this blog comes in as ersatz comments on The hypothalamus couples with the brainstem to cause migraines. I don’t know what it is about the post that attracts internet bots.

The unwanted attention is too bad because the post represents a good personal illustration of “changes in the neural response to painful stimuli.” Last year I experienced three three-day migraines in one month as did the study’s subject. This led to me cycling through a half-dozen medications in an effort to address the migraine causes.

None of the medications proved to be effective at treating the causes. I found one that interrupted the progress of migraines – sumatriptan, a serotonin receptor agonist. I’ve used it when symptoms start, and the medication has kept me from having a full-blown migraine episode in the past year.

1. It may be argued that migraine headache tendencies are genetically inherited. Supporting personal evidence is that both my mother and younger sister have migraine problems. My father, older sister, and younger brother didn’t have migraine problems. Familial genetic inheritance usually isn’t the whole story of diseases, though.

2. Migraine headaches may be an example of diseases that are results of how humans have evolved. From Genetic imprinting, sleep, and parent-offspring conflict:

“Evolutionary theory predicts: that which evolves is not necessarily that which is healthy.

Why should pregnancy not be more efficient and more robust than other physiological systems, rather than less? Crucial checks, balances and feedback controls are lacking in the shared physiology of the maternal–fetal unit.“

Both migraine causes and effects may be traced back to natural lacks of feedback loops. These lacks demonstrate that such physiological feedback wasn’t evolutionarily necessary in order for humans to survive and reproduce.

3. Examples of other processes occurring during prenatal development that also lack feedback loops, and their subsequent diseases, are:

A. Hypoxic conditions per Lack of oxygen’s epigenetic effects are causes of the fetus later developing:

  • “age-related macular degeneration
  • cancer progression
  • chronic kidney disease
  • cardiomyopathies
  • adipose tissue fibrosis
  • inflammation
  • detrimental effects which are linked to epigenetic changes.”

B. Stressing pregnant dams per Treating prenatal stress-related disorders with an oxytocin receptor agonist caused fetuses to develop a:

and abnormalities:

  • in social behavior,
  • in the HPA response to stress, and
  • in the expression of stress-related genes in the hippocampus and amygdala.”

1. What would be a treatment that could cure genetic causes for migraines?

I don’t know of any gene therapies.

2. What treatments could cure migraines caused by an evolved lack of feedback mechanisms?

We humans are who we have become, unless and until we can change original causes. Can we deal with “changes in the neural response to painful stimuli” without developing hopes for therapies or technologies per Differing approaches to a life wasted on beliefs?

3. What treatments could cure prenatal epigenetic causes for migraines?

The only effective solution I know of that’s been studied in humans is to prevent adverse conditions like hypoxia from taking place during pregnancy. The critical periods of our physical development are over once we’re adults, and we can’t unbake a cake.

Maybe science will offer other possibilities. Maybe researchers could do more than their funding sponsors expect?

Differing approaches to a life wasted on beliefs

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Anterior cingulate cortex, Beliefs, Brain development, Brain hemispheres, Brainstem, Cerebrum, Cortisol, Dopamine, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Oxytocin, Primal Therapy, Serotonin, Stress, Thalamus , , , , , , , , , ,

Let’s start by observing that people structure their lives around beliefs. As time goes on, what actions would a person have taken to ward off non-confirming evidence?

One response may be that they would engage in ever-increasing efforts to develop new beliefs that justified how they spent their one precious life’s time so far.

Such was my take on beliefs embedded in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684598/pdf/PSYCHIATRY2017-5491812.pdf “Epigenetic and Neural Circuitry Landscape of Psychotherapeutic Interventions”:

“Animal models have shown the benefits of continued environmental enrichment (EE) on psychopathological phenotypes, which carries exciting translational value.

This paper posits that psychotherapy serves as a positive environmental input (something akin to EE).”

The author conveyed his belief that wonderful interventions were going to happen in the future. However, when scrutinized, most human studies have demonstrated NULL effects of psychotherapeutic interventions on causes. Without sound evidence that treatments affect causes, his belief seemed driven by something else.

The author cited findings of research like A problematic study of oxytocin receptor gene methylation, childhood abuse, and psychiatric symptoms as supporting external interventions to tamp down symptoms of patients’ presenting problems. Did any of the 300+ cited references concern treatments where patients instead therapeutically addressed their problems’ root causes?

For an analogous religious example, a person’s belief caused him to spend years of his life trying to convince men to act so that they could get their own planet after death, and trying to convince women to latch onto men who had this belief. A new and apparently newsworthy belief developed from his underlying causes:

“The founder and CEO of neuroscience company Kernel wants “to expand the bounds of human intelligence.” He is planning to do this with neuroprosthetics; brain augmentations that can improve mental function and treat disorders. Put simply, Kernel hopes to place a chip in your brain.

He was raised as a Mormon in Utah and it was while carrying out two years of missionary work in Ecuador that he was struck by what he describes as an “overwhelming desire to improve the lives of others.”

He suffered from chronic depression from the ages of 24 to 34, and has seen his father and stepfather face huge mental health struggles.”

https://www.theguardian.com/small-business-network/2017/dec/14/humans-20-meet-the-entrepreneur-who-wants-to-put-a-chip-in-your-brain “Humans 2.0: meet the entrepreneur who wants to put a chip in your brain”

The article stated that he had given up Mormonism. There was nothing to suggest, though, that he had therapeutically addressed any underlying causes for his misdirected thoughts, feelings, and behavior.

So he developed other beliefs instead.

What can people do to keep their lives from being wasted on beliefs? As mentioned in What was not, is not, and will never be:

“The problem is that spending our time and efforts on these ideas, beliefs, and behaviors won’t ameliorate their motivating causes. Our efforts only push us further away from our truths, with real consequences: a wasted life.”

The goal of the therapeutic approach advocated by Dr. Arthur Janov’s Primal Therapy is to remove the force of presenting problems’ motivating causes. Success in reaching this goal is realized when patients become better able to live their own lives.

Do you have your family’s detailed medical histories?

gettingwell4 4-5 stars Advanced knowledge, Brain development, Cerebrum, Cortisol, Epigenetics, Hypothalamus, Limbic system, Neurochemicals, Stress , , , , , ,

Imagine that you were a parent who puzzled over the mystery of your pre-teen daughter’s hyperactive behavior. Without detailed family medical histories, would anyone recognize this as a preprogammed phenotype?

Could anyone trace the daughter’s behavior back to her maternal great-grandmother being treated with glucocorticoids near the end of the second trimester of carrying her grandfather?

Such was a finding of a 2017 Canadian guinea pig study that was undertaken to better inform physicians of the transgenerationally inherited epigenetic effects of glucocorticoid treatments commonly prescribed during human pregnancies:

“This study presents the first evidence that prenatal treatment with sGC [synthetic glucocorticoid] results in transgenerational paternal transmission of hyperactivity and altered hypothalamic gene expression through three generations of young offspring. Female offspring appear to be more sensitive than male offspring to the programming effects of sGC, which suggests an interaction between sGC and sex hormones or sex-linked genes. Paternal transmission to F3 strongly implicates epigenetic mechanisms in the process of transmission, and small noncoding RNAs likely play a major role.”

Some details of the study included:

Veh[icle] was the control group initially treated with saline.

The study was informative and conclusive for the aspects studied. From the Methods section:

“Data from same-sex littermates were meaned to prevent litter bias. Sample sizes (N) correspond to independent litters, and not to the total number of offspring across all litters.

Power analyses based on previous studies determined N ≥ 8 sufficient to account for inter-litter variability and detect effects in the tests performed.”

https://www.nature.com/articles/s41598-017-11635-w “Prenatal Glucocorticoid Exposure Modifies Endocrine Function and Behaviour for 3 Generations Following Maternal and Paternal Transmission”

What is a father’s role in epigenetic inheritance?

gettingwell4 < 0 Detracted from science, Beliefs, Brain development, Cerebrum, Epigenetics, Stress , , , ,

The agenda of this 2017 Danish review was to establish a paternal role in intergenerational and transgenerational epigenetic inheritance of metabolic diseases:

“There are four windows of susceptibility which have major importance for epigenetic inheritance of acquired paternal epigenetic changes:

  1. paternal primordial germ cell (PGC) development,
  2. prospermatogonia stages,
  3. spermatogenesis, and
  4. during preimplantation.”

The review was a long read as the authors discussed animal studies. When it came to human studies near the paper’s end, though, the tone was of a “we know this is real, we just have to find it” variety. The authors acknowledged:

“To what extent the described DNA methylation changes influence the future health status of offspring by escaping remodeling in the preimplantation period as well as in future generations by escaping remodeling in PGC remodeling has yet to be determined.

These studies have not yet provided an in-depth understanding of the specific mechanisms behind epigenetic inheritance or exact effect size for the disease risk in offspring.

Pharmacological approaches have reached their limits..”

before presenting their belief that a hypothetical series of future CRISPR-Cas9 experiments will demonstrate the truth of their agenda.

The review focused on 0.0001% of the prenatal period for what matters with the human male – who he was at the time of a Saturday night drunken copulation – regarding intergenerational and transgenerational epigenetic inheritance of metabolic diseases.

The human female’s role – who she was at conception AND THEN what she does or doesn’t do during the remaining 99.9999% of the prenatal period to accommodate the fetus and prevent further adverse epigenetic effects from being intergenerationally and transgenerationally transmitted  – wasn’t discussed.

Who benefits from this agenda’s narrow focus?

If the review authors sincerely want to:

“Raise societal awareness of behavior to prevent a further rise in the prevalence of metabolic diseases in future generations..”

then EARN IT! Design and implement HUMAN studies to test what’s already known from epigenetic inheritance animal studies per Experience-induced transgenerational programming of neuronal structure and functions. Don’t disguise beliefs with the label of science.

http://jme.endocrinology-journals.org/content/early/2017/12/04/JME-17-0189.full.pdf “DNA methylation in epigenetic inheritance of metabolic diseases through the male germ line”

An update on brain zapping

gettingwell4 2-3 stars Required further work, Cerebrum, Limbic system, Thalamus ,

This 2017 general-audience article entitled Ultrasound for the brain provided a hyped update on brain zapping:

“Ultrasound could potentially treat other movement disorders, as well as depression, anxiety and a host of intract­able neuropsychiatric disorders..

This could be a breakthrough..

Researchers hope one day to help people with neuropsychiatric conditions by repairing or resetting the relevant neural pathways..

The potential advantages, especially for deep brain areas, are huge..”

Though not the main thrust of the article, another potential use of ultrasound would be to activate drugs delivered to a specific area, as this image portrays:

Vanderbilt University was again at the forefront of brain zapping, as noted in What’s an appropriate control group for a schizophrenia study? for example. I hope the disclosures for subjects participating in Vanderbilt’s brain-zapping studies made it clear that:

“At high intensities, such as those used to relieve essential tremor, ultrasound’s effects are largely thermal: the tissue heats up and cells die.”

Comments are disabled because this post has somehow become a target for spammers. Readers can click the above control group link to comment.

Beliefs about genetic and environmental influences in twin studies

gettingwell4 < 0 Detracted from science, Beliefs, Cerebrum, Epigenetics ,

This 2017 Penn State simulation found:

“By taking advantage of the natural variation in genetic relatedness among identical (monozygotic: MZ) and fraternal (dizygotic: DZ) twins, twin studies are able to estimate genetic and environmental contributions to complex human behaviors.

In the standard biometric model when MZ or DZ twin similarity differs from 1.00 or 0.50, respectively, the variance that should be attributed to genetic influences is instead attributed to nonshared environmental influences, thus deflating the estimates of genetic influences and inflating the estimates of nonshared environmental influences.

Although estimates of genetic and nonshared environmental influences from the standard biometric model were found to deviate from “true” values, the bias was usually smaller than 10% points indicating that the interpretations of findings from previous twin studies are mostly correct.”

The study model’s input was five phenotypes that varied the degrees of:

  1. Genetic and epigenetic heritability;
  2. Shared environmental factors; and
  3. Nonshared environmental factors.

Item 1 above was different than the standard model’s treatment of heritable factors, which considers only additive genetic influences.

The authors cited studies for moderate and significant shared environmental influences in child and adolescent psychopathology and parenting to support the model’s finding that overall, item 2 above wasn’t underestimated.

I wasn’t satisfied with the simulation’s description of item 1 above. With

  1. Environmental influences accounted for elsewhere, and
  2. No references to transgenerational epigenetic inheritance,
  3. Randomness seemed to be the only remaining explanation for an epigenetic heritability factor.

Inserting the model’s non-environmental randomness explanation for epigenetic heritability into the abstract’s statement above exposed the non sequitur:

In the standard biometric model when MZ or DZ twin similarity differs from 1.00 or 0.50, respectively, the variance that should be attributed to genetic [and non-environmental stochastic heritability] influences is instead attributed to nonshared environmental influences, thus deflating the estimates of genetic [and non-environmental stochastic heritability] influences and inflating the estimates of nonshared environmental influences.

Why did the researchers design their model with an adjustment for non-environmental epigenetic heritability? Maybe it had something to do with:

“Estimates of genetic and nonshared environmental influences from the standard biometric model were found to deviate from “true” values.”

In any event, I didn’t see that this simulation was much more than an attempt to reaffirm a belief that:

“The interpretations of findings from previous twin studies are mostly correct.”

Empirical rather than simulated findings in human twin study research are more compelling, such as The primary causes of individual differences in DNA methylation are environmental factors with its finding:

“Differential methylation is primarily non-genetic in origin, with non-shared environment accounting for most of the variance. These non-genetic effects are mainly tissue-specific.

The full scope of environmental variation remains underappreciated.”

https://link.springer.com/article/10.1007/s10519-017-9875-x “The Impact of Variation in Twin Relatedness on Estimates of Heritability and Environmental Influences” (not freely available)

One example of how experience changes the brain

gettingwell4 4-5 stars Advanced knowledge, Brain development, Cerebrum, Epigenetics, Hippocampus, Hypothalamus, Limbic system, Memory ,

This 2017 California rodent study found:

“Neural representations within the mouse hypothalamus, that underlie innate social behaviours, are shaped by social experience.

In sexually and socially experienced adult males, divergent and characteristic neural ensembles represented male versus female conspecifics [members of the same species]. However, in inexperienced adult males, male and female intruders activated overlapping neuronal populations.

Sex-specific neuronal ensembles gradually separated as the mice acquired social and sexual experience. In mice permitted to investigate but not to mount or attack conspecifics, ensemble divergence did not occur. However, 30 minutes of sexual experience with a female was sufficient to promote the separation of male and female ensembles.

These observations uncover an unexpected social experience-dependent component to the formation of hypothalamic neural assemblies controlling innate social behaviours. More generally, they reveal plasticity and dynamic coding in an evolutionarily ancient deep subcortical structure that is traditionally viewed as a ‘hard-wired’ system.”

Hat tip to Neuroskeptic for both alerting me to the study and simplifying its overly-dense graphics.

http://www.nature.com/nature/journal/v550/n7676/full/nature23885.html “Social behaviour shapes hypothalamic neural ensemble representations of conspecific sex” (not freely available)

Do preventive interventions for children of mentally ill parents work?

gettingwell4 < 0 Detracted from science, Beliefs, Cerebrum, Epigenetics

The fifth and final paper of Transgenerational epigenetic inheritance week was a 2017 German/Italian meta-analysis of psychiatric treatments involving human children:

“The transgenerational transmission of mental disorders is one of the most significant causes of psychiatric morbidity. Several risk factors for children of parents with mental illness (COPMI) have been identified in numerous studies and meta-analyses.

There is a dearth of high quality studies that effectively reduce the high risk of COPMI for the development of mental disorders.”

I found the study by searching a medical database on the “transgenerational” term. The authors fell into the trap of misusing “transgenerational” instead of “intergenerational” to describe individuals in different generations.

Per the definitions in A review of epigenetic transgenerational inheritance of reproductive disease and Transgenerational effects of early environmental insults on aging and disease, for the term “transgenerational transmission” to apply, the researchers needed to provide evidence in at least the next 2 male and/or 3 female generations of:

“Altered epigenetic information between generations in the absence of continued environmental exposure.”

The meta-analysis didn’t provide evidence for “transgenerational transmission of mental disorders.”

Several aspects of the meta-analysis stood out:

  1. Infancy was the earliest period of included studies, and studies of treatments before the children were born were excluded;
  2. Parents had to be diagnosed with a mental illness for the study to be included;
  3. Studies with children diagnosed with a mental illness were excluded; and
  4. Studies comparing more than one type of intervention were excluded.

Fifty worldwide studies from 1983 through 2014 were selected for the meta-analysis.

Per item 1 above, if a researcher doesn’t look for something, it’s doubtful that they will find it. As shown in the preceding papers of Transgenerational epigenetic inheritance week, the preconception through prenatal periods are where the largest epigenetic effects on an individual are found. There are fewer opportunities for effective “preventive interventions” in later life compared with these early periods.

Science provides testable explanations and predictions. The overall goal of animal studies is to help humans.

Animal studies provide explanations and predictions for the consequences of environmental insults to the human fetus – predictable disrupted neurodevelopment with subsequent deviated behaviors and other lifelong damaging effects in the F1 children. The first four papers I curated during Transgenerational epigenetic inheritance week provided samples of which of these and/or other harmful effects may be predictably found in F2 grandchildren, F3 great-grandchildren, and future human generations.

When will human transgenerational epigenetic inheritance be taken seriously? Is the root problem that human societies don’t give humans in the fetal stage of life a constituency, or protection against mistreatment, or even protection against being arbitrarily killed?

The default answer to the meta-analysis title “Do preventive interventions for children of mentally ill parents work?” is No. As for the “dearth of high quality studies” complaint: when treatments aren’t effective, is the solution to do more of them?

No.

The researchers provided an example of the widespread belief that current treatments for “psychiatric morbidity” are on the right path, and that the usual treatments – only done more rigorously – will eventually provide unquestionable evidence that they are effective.

This belief is already hundreds of years old. How much longer will this unevidenced belief infect us?

http://journals.lww.com/co-psychiatry/Abstract/2017/07000/Do_preventive_interventions_for_children_of.9.aspx “Do preventive interventions for children of mentally ill parents work? Results of a systematic review and meta-analysis” (not freely available)

“Transgenerationally” inherited epigenetic effects of fetal alcohol exposure

gettingwell4 2-3 stars Required further work, Acetylcholine, Brain development, Cerebrum, Epigenetics, Hippocampus, Limbic system, Memory, Neurochemicals , , , , , ,

The fourth paper of Transgenerational epigenetic inheritance week was a 2016 German rodent study of of improperly-termed “transgenerational” epigenetic effects of alcohol:

“We investigated 2 generations of offspring born to alcohol-treated mothers. Here, we show that memory impairment and reduced synthesis of acetylcholine occurs in both F1 (exposed to ethanol in utero) and F2 generation (never been exposed to ethanol). Effects in the F2 generation are most likely consequences of transgenerationally transmitted epigenetic modifications in stem cells induced by alcohol.

The results further suggest an epigenetic trait for an anticholinergic endophenotype associated with cognitive dysfunction which might be relevant to our understanding of mental impairment in neurodegenerative disorders such as Alzheimer’s disease and related disorders.”

F0 generation mothers modeled human fetal alcohol syndrome. They were exposed to ethanol gradually up to 20%, then mated. The 20% ethanol intake level was maintained until the F1 generation pups were born, then gradually diminished to 0%. After a ten-day wait, an eight-week handling and shaping period started, followed by five weeks of behavioral testing.

The F1 children and F2 grandchildren started an eight-week handling and shaping period after young adulthood, followed by five weeks of behavioral testing. The F1 children were mated after behavioral testing.

The F0 parents showed no significant differences in working memory and reference memory compared with controls. Both the F1 children and F2 grandchildren were significantly impaired in the same tests compared with controls, with the F1 children performing worse than the F2 grandchildren. No sex-dependent differences were noted.

After behavioral impairments due to intergenerational epigenetic modifications were established, the F2 grandchildren received treatments to ascertain the contribution of cholinergic dysfunction in their behavioral impairments. It was confirmed, as an acetylcholine esterase inhibitor that crosses the blood-brain barrier almost completely erased working-memory and reference-memory performance deficits.

Items in the Discussion section included:

  • A dozen studies from 2014-2016 were cited for epigenetic mechanisms of inheritance stemming from parental alcohol consumption; and
  • Transgenerational inheritance of alcohol-induced neurodevelopmental deficits may involve epigenetic mechanisms that are resistant to developmental clearance.

As argued in Transgenerational effects of early environmental insults on aging and disease and A review of epigenetic transgenerational inheritance of reproductive disease, testing of F3 great-grandchildren was needed in order to establish transgenerational vs. intergenerational results. A F3 generation necessarily controls for the variable of F2 direct germline exposure.

http://www.neurobiologyofaging.org/article/S0197-4580(16)30303-7/pdf “Transgenerational transmission of an anticholinergic endophenotype with memory dysfunction” (not freely available)