Resiliency in stress responses

This 2018 US Veterans Administration review subject was resiliency and stress responses:

Neurobiological and behavioral responses to stress are highly variable. Exposure to a similar stressor can lead to heterogeneous outcomes — manifesting psychopathology in one individual, but having minimal effect, or even enhancing resilience, in another.

We highlight aspects of stress response modulation related to early life development and epigenetics, selected neurobiological and neurochemical systems, and a number of emotional, cognitive, psychosocial, and behavioral factors important in resilience.”

The review cited studies I’ve previously curated:


There were two things I didn’t understand about this review. The first was why the paper isn’t freely available. It’s completely paid for by the US taxpayer, and no copyright is claimed. I recommend contacting the authors for a copy.

The second was why the VA hasn’t participated in either animal or human follow-on studies to the 2015 Northwestern University GABAergic mechanisms regulated by miR-33 encode state-dependent fear. That study’s relevance to PTSD, this review’s subject, and the VA’s mission is too important to ignore. For example:

“Fear-inducing memories can be state dependent, meaning that they can best be retrieved if the brain states at encoding and retrieval are similar.

“It’s difficult for therapists to help these patients,” Radulovic said, “because the patients themselves can’t remember their traumatic experiences that are the root cause of their symptoms.”

The findings imply that in response to traumatic stress, some individuals, instead of activating the glutamate system to store memories, activate the extra-synaptic GABA system and form inaccessible traumatic memories.”

I curated the research in A study that provided evidence for basic principles of Primal Therapy. These researchers have published several papers since then. Here are the abstracts from three of them:

Experimental Methods for Functional Studies of microRNAs in Animal Models of Psychiatric Disorders

“Pharmacological treatments for psychiatric illnesses are often unsuccessful. This is largely due to the poor understanding of the molecular mechanisms underlying these disorders. We are particularly interested in elucidating the mechanism of affective disorders rooted in traumatic experiences.

To date, the research of mental disorders in general has focused on the causal role of individual genes and proteins, an approach that is inconsistent with the proposed polygenetic nature of these disorders. We recently took an alternative direction, by establishing the role of miRNAs in the coding of stress-related, fear-provoking memories.

Here we describe in detail our work on the role of miR-33 in state-dependent learning, a process implicated in dissociative amnesia, wherein memories formed in a certain brain state can best be retrieved if the brain is in the same state. We present the specific experimental approaches we apply to study the role of miRNAs in this model and demonstrate that miR-33 regulates the susceptibility to state-dependent learning induced by inhibitory neurotransmission.”

Neurobiological mechanisms of state-dependent learning

“State-dependent learning (SDL) is a phenomenon relating to information storage and retrieval restricted to discrete states. While extensively studied using psychopharmacological approaches, SDL has not been subjected to rigorous neuroscientific study.

Here we present an overview of approaches historically used to induce SDL, and highlight some of the known neurobiological mechanisms, in particular those related to inhibitory neurotransmission and its regulation by microRNAs (miR).

We also propose novel cellular and circuit mechanisms as contributing factors. Lastly, we discuss the implications of advancing our knowledge on SDL, both for most fundamental processes of learning and memory as well as for development and maintenance of psychopathology.”

Neurobiological correlates of state-dependent context fear

“Retrieval of fear memories can be state-dependent, meaning that they are best retrieved if the brain states at encoding and retrieval are similar. Such states can be induced by activating extrasynaptic γ-aminobutyric acid type A receptors (GABAAR) with the broad α-subunit activator gaboxadol. However, the circuit mechanisms and specific subunits underlying gaboxadol’s effects are not well understood.

Here we show that gaboxadol induces profound changes of local and network oscillatory activity, indicative of discoordinated hippocampal-cortical activity, that were accompanied by robust and long-lasting state-dependent conditioned fear. Episodic memories typically are hippocampus-dependent for a limited period after learning, but become cortex-dependent with the passage of time.

In contrast, state-dependent memories continued to rely on hippocampal GABAergic mechanisms for memory retrieval. Pharmacological approaches with α- subunit-specific agonists targeting the hippocampus implicated the prototypic extrasynaptic subunits (α4) as the mediator of state-dependent conditioned fear.

Together, our findings suggest that continued dependence on hippocampal rather than cortical mechanisms could be an important feature of state-dependent memories that contributes to their conditional retrieval.”


Here’s an independent 2017 Netherlands/UC San Diego review that should bring these researchers’ efforts to the VA’s attention:

MicroRNAs in Post-traumatic Stress Disorder

“Post-traumatic stress disorder (PTSD) is a psychiatric disorder that can develop following exposure to or witnessing of a (potentially) threatening event. A critical issue is to pinpoint the (neuro)biological mechanisms underlying the susceptibility to stress-related disorder such as PTSD, which develops in the minority of ~15% of individuals exposed to trauma.

Over the last few years, a first wave of epigenetic studies has been performed in an attempt to identify the molecular underpinnings of the long-lasting behavioral and mental effects of trauma exposure. The potential roles of non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) in moderating or mediating the impact of severe stress and trauma are increasingly gaining attention. To date, most studies focusing on the roles of miRNAs in PTSD have, however, been completed in animals, using cross-sectional study designs and focusing almost exclusively on subjects with susceptible phenotypes.

Therefore, there is a strong need for new research comprising translational and cross-species approaches that use longitudinal designs for studying trajectories of change contrasting susceptible and resilient subjects. The present review offers a comprehensive overview of available studies of miRNAs in PTSD and discusses the current challenges, pitfalls, and future perspectives of this field.”

Here’s a 2017 Netherlands human study that similarly merits the US Veterans Administration’s attention:

Circulating miRNA associated with posttraumatic stress disorder in a cohort of military combat veterans

“Posttraumatic stress disorder (PTSD) affects many returning combat veterans, but underlying biological mechanisms remain unclear. In order to compare circulating micro RNA (miRNA) of combat veterans with and without PTSD, peripheral blood from 24 subjects was collected following deployment, and isolated miRNA was sequenced.

PTSD was associated with 8 differentially expressed miRNA. Pathway analysis shows that PTSD is related to the axon guidance and Wnt signaling pathways, which work together to support neuronal development through regulation of growth cones. PTSD is associated with miRNAs that regulate biological functions including neuronal activities, suggesting that they play a role in PTSD symptomatology.”


See the below comments for reasons why I downgraded this review’s rating.

https://link.springer.com/article/10.1007/s11920-018-0887-x “Stress Response Modulation Underlying the Psychobiology of Resilience” (not freely available)

The lifelong impact of maternal postpartum behavior

This 2018 French/Italian/Swiss rodent study was an extension of the work done by the group of researchers who performed Prenatal stress produces offspring who as adults have cognitive, emotional, and memory deficiencies and Treating prenatal stress-related disorders with an oxytocin receptor agonist:

“Reduction of maternal behavior [nursing behavior, grooming, licking, carrying pups] was predictive of behavioral disturbances in PRS [prenatally restraint stressed] rats as well as of the impairment of the oxytocin and its receptor gene expression.

Postpartum carbetocin [an oxytocin receptor agonist unavailable in the US] corrected the reduction of maternal behavior induced by gestational stress as well as the impaired oxytocinergic system in the PRS progeny, which was associated with reduced risk-taking behavior.

Moreover, postpartum carbetocin had an anti-stress effect on HPA [hypothalamic-pituitary-adrenal] axis activity in the adult PRS progeny and increased hippocampal mGlu5 [type 5 metabotropic glutamate] receptor expression in aging.

Early postpartum carbetocin administration to the dam enhances maternal behavior and prevents all the pathological outcomes of PRS throughout the entire lifespan of the progeny..proves that the defect in maternal care induced by gestational stress programs the development of the offspring.


This chart from Figure 4 summarized the behavioral performance of aged adult male progeny in relation to the experimental variables of:

  1. Stress administered to the mothers three times daily every day during the second half of pregnancy up until delivery; and
  2. The effects on the mothers’ behavior of daily carbetocin administration during postpartum days 1 through 7.

The symbols denote which of these relationships had statistically significant effects:

  • “* p [Pearson’s correlation coefficient] < 0.05 PRS-Saline vs. CONT-Saline;
  • # p < 0.05 PRS-Carbetocin vs. the PRS-Saline group.”

There are many interesting aspects to this study. Ask the corresponding coauthor Dr. Sara Morley-Fletcher at sara.morley-fletcher@univ-lille1.fr for a copy.

One place the paper referenced the researchers’ previous studies was in this context:

“Postpartum carbetocin administration reversed the same molecular and behavioral parameters in the hippocampus, as does adult chronic carbetocin treatment, i.e. it led to a correction of the HPA axis negative feedback mechanisms, stress and anti-stress gene expression, and synaptic glutamate release. The fact that postpartum carbetocin administration [to the stressed mothers in this study] had the same effect [on the PRS infants in this study] as adult carbetocin treatment [to the PRS offspring in the previous study] indicates a short-term effect of carbetocin when administered in adulthood and a reprogramming (long-term) effect lasting until an advanced age when administered in early development.”

This group’s research seems to be constrained to treatments of F0 and F1 generations. What intergenerational and transgenerational effects would they possibly find by extending research efforts to F2 and F3 generations?


As the study may apply to humans:

The study demonstrated that stresses during the second half of pregnancy had lifelong impacts on both the mothers’ and offsprings’ biology and behavior. Studies and reviews that attribute similar human biological and behavioral conditions to unknown causes, or shuffle them into the black box of individual differences, should be recognized as either disingenuous or insufficient etiological investigations.

The study showed that prevention of gestational stress was a viable strategy. The control group progeny’s biology and behavior wasn’t affected by carbetocin administration to their mothers because neither they nor their mothers had experience-dependent epigenetic deficiencies.

The study demonstrated a biological and behavioral cure for the PRS offspring by changing their stressed mothers’ behaviors during a critical period of their development. The above excerpt characterized improving the mothers’ behaviors as a long-term cure for the PRS descendants, as opposed to the short-term cure of administering carbetocin to the PRS children when they were adults.

What long-term therapies may be effective for humans who had their developmental trajectories altered by their mothers’ stresses during their gestation, or who didn’t get the parental care they needed when they needed it?

https://www.sciencedirect.com/science/article/pii/S0161813X18301062 “Reduced maternal behavior caused by gestational stress is predictive of life span changes in risk-taking behavior and gene expression due to altering of the stress/anti-stress balance” (not freely available)

Sleep and adult brain neurogenesis

This 2018 Japan/Detroit review subject was the impact of sleep and epigenetic modifications on adult dentate gyrus neurogenesis:

“We discuss the functions of adult‐born DG neurons, describe the epigenetic regulation of adult DG neurogenesis, identify overlaps in how sleep and epigenetic modifications impact adult DG neurogenesis and memory consolidation..

Whereas the rate of DG neurogenesis declines exponentially with age in most mammals, humans appear to exhibit a more modest age‐related reduction in DG neurogenesis. Evidence of adult neurogenesis has also been observed in other regions of the mammalian brain such as the subventricular zone, neocortex, hypothalamus, amygdala, and striatum.

Adult‐born DG neurons functionally integrate into hippocampal circuitry and play a special role in cognition during a period of heightened excitability and synaptic plasticity occurring 4–6 weeks after mitosis. Adult DG neurogenesis is regulated by a myriad of intrinsic and extrinsic factors, including:

  • drugs,
  • diet,
  • inflammation,
  • physical activity,
  • environmental enrichment,
  • stress, and
  • trauma.”


Some of what the review stated was contradicted by other evidence. For example, arguments for sleep were based on the memory consolidation paradigm, but evidence against memory consolidation wasn’t cited for balanced consideration.

It reminded me of A review that inadvertently showed how memory paradigms prevented relevant research. That review’s citations included a study led by one of those reviewers where:

“The researchers elected to pursue a workaround of the memory reconsolidation paradigm when the need for a new paradigm of enduring memories directly confronted them!”

Some of what this review stated was speculation. I didn’t quote any sections after:

 “We go one step further and propose..”

The review also had a narrative directed toward:

“Employing sleep interventions and epigenetic drugs..”

It’s storytelling rather than pursuing the scientific method when reviewers approach a topic as these reviewers did.

Instead of reading a directed narrative, read this informative blog post from a Canadian researcher. The post provided scientific contexts to summarize what was and wasn’t known in 2018 about human neurogenesis.

http://onlinelibrary.wiley.com/doi/10.1002/stem.2815/epdf “Regulatory Influence of Sleep and Epigenetics on Adult Hippocampal Neurogenesis and Cognitive and Emotional Function”

Sex-specific impacts of childhood trauma

This 2018 Canadian paper reviewed evidence for potential sex-specific differences in the lasting impacts of childhood trauma:

“This paper will provide a contextualized summary of neuroendocrine, neuroimaging, and behavioral epigenetic studies on biological sex differences contributing to internalizing psychopathology, specifically posttraumatic stress disorder and depression, among adults with a history of childhood abuse.

Given the breadth of this review, we limit our definition [of] trauma to intentional and interpersonal experiences (i.e., childhood abuse and neglect) in childhood. Psychopathological outcomes within this review will be limited to commonly explored internalizing disorders, specifically PTSD and depression.

Despite the inconsistent and limited findings in this review, a critical future consideration will be whether the biological effects of early life stress can be reversed in the face of evidence-based behavioral interventions, and furthermore, whether these changes may relate to potentially concurrent reductions in susceptibility to negative mental health outcomes.”


It was refreshing to read a paper where the reviewers often interrupted the reader’s train of thought to interject contradictory evidence, and display the scientific method. For example, immediately after citing a trio of well-respected studies that found:

“Psychobiological research on relationships linking impaired HPA axis functioning and adult internalizing disorders are suggestive of lower basal and afternoon levels of plasma cortisol in PTSD phenotype.”

the reviewers stated:

“However, a recent meta-analysis suggests no association between basal cortisol with PTSD.”

and effectively ended the cortisol discussion with:

“Findings are dependent upon variance in extenuating factors, including but not limited to, different measurements of:

  • early adversity,
  • age of onset,
  • basal cortisol levels, as well as
  • trauma forms and subtypes, and
  • presence and severity of psychopathology symptomology.”

The reviewers also provided good summaries of aspects of the reviewed subject. For example, the “Serotonergic system genetic research, childhood trauma and risk of psychopathology” subsection ended with:

“Going forward, studies must explore the longitudinal effects of early trauma on methylation as well as comparisons of multiple loci methylation patterns and interactions to determine the greatest factors contributing to health outcomes. Only then, can we start to consider the role of sex in moderating risk.”


I didn’t agree with the cause-ignoring approach of the behavior therapy mentioned in the review. Does it make sense to approach one category of symptoms:

“the biological effects of early life stress”

by treating another category of symptoms?

“can be reversed in the face of evidence-based behavioral interventions.”

But addressing symptoms instead of the sometimes-common causes that generate both biological and behavioral effects continues to be the direction.

After receiving short-term symptom relief, wouldn’t people prefer treatments of originating causes so that their various symptoms don’t keep bubbling up? Why wouldn’t research paradigms be aligned accordingly?

I was encouraged by the intergenerational and transgenerational focus of one of the reviewer’s research:

“Dr. Gonzalez’s current research focus is to understand the mechanisms by which early experiences are transmitted across generations and how preventive interventions may affect this transmission.”

This line of hypotheses requires detailed histories, and should uncover causes for many effects that researchers may otherwise shrug off as unexplainable individual differences. Its aims include the preconception through prenatal periods when both the largest and the largest number of epigenetic changes occur, and is when our susceptibility and sensitivity to our environment is greatest. There are fewer opportunities for effective “preventive interventions” in later life compared with these early periods.

Unlike lab rats, women and men can reach some degree of honesty about our early lives’ experiential causes of ongoing adverse effects. Experiential therapies that allow humans to potentially change their responses to these causes deserve more investigation than do therapies that apply external “interventions.”

https://www.sciencedirect.com/science/article/pii/S0272735817302647 “Biological alterations affecting risk of adult psychopathology following childhood trauma: A review of sex differences” (not freely available) Thanks to lead author Dr. Ashwini Tiwari for providing a copy.

Epigenetic study methodologies improved in 2017

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?

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

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.

Transgenerational pathological traits induced by prenatal immune activation

The third paper of Transgenerational epigenetic inheritance week was a 2016 Swiss rodent study of immune system epigenetic effects:

“Our study demonstrates for, we believe, the first time that prenatal immune activation can negatively affect brain and behavioral functions in multiple generations. These findings thus highlight a novel pathological aspect of this early-life adversity in shaping disease risk across generations.”

The epigenetic effects noted in the initial round of experiments included:

  • F1 child and F2 grandchild impaired sociability;
  • F1 and F2 abnormal fear expression;
  • F1 but not F2 sensorimotor gating deficiencies; and
  • F2 but not F1 behavioral despair associated with depressive-like behavior.

These transgenerational effects emerged in both male and female offspring. The prenatal immune activation timing corresponded to the middle of the first trimester of human pregnancy.

The effects were found to be mediated by the paternal but not maternal lineage. The researchers didn’t develop a maternal lineage F3 great-grandchild generation.

The next round of experiments done with the paternal lineage F3 great-grandchildren noted these epigenetic effects:

  • The F3 great-grandchildren had impaired sociability, abnormal fear expression and behavioral despair; and
  • The F3 great-grandchildren had normal sensorimotor gating.

Since the first round of tests didn’t show sex-dependent effects, the F3 great-grandchildren were male-only to minimize the number of animals.

Samples of only the amygdalar complex were taken to develop findings of transcriptomic effects of prenatal immune activation.

Items in the Discussion section included:

  1. The F2 grandchild and F3 great-grandchild generations’ phenotype of impaired sociability, abnormal fear expression and behavioral despair demonstrated that prenatal immune activation likely altered epigenetic marks in the germ line of the F1 children which resisted erasure and epigenetic reestablishment during germ cell development.
  2. Abnormal F1 child sensorimotor gating followed by normal F2 grandchild and F3 great-grandchild sensorimotor gating demonstrated that prenatal immune activation may also modify somatic but not germ cells.
  3. Non-significant F1 child behavioral despair followed by F2 grandchild and F3 great-grandchild behavioral despair demonstrated that prenatal immune activation may modify F1 germ cells sufficiently to develop a transgenerational phenotype, but unlike item 1 above, somatic cells were insufficiently modified, and the phenotype skipped the F1 children.
  4. Studies were cited that prenatal immune activation later in the gestational process may produce different effects.

The initial round of experiments wasn’t definitive for the maternal lineage. 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 maternal lineage F3 great-grandchildren was needed to control for the variable of direct F2 grandchild germ-line exposure.

Also, effects that didn’t reach statistical significance in the maternal lineage F1 children and F2 grandchildren may have been different in the F3 great-grandchildren. The researchers indirectly acknowledged this lack by noting that these and other effects of immune challenges in a maternal lineage weren’t excluded by the study.

https://www.nature.com/mp/journal/v22/n1/pdf/mp201641a.pdf “Transgenerational transmission and modification of pathological traits induced by prenatal immune activation” (not freely available)


The study’s lead researcher authored a freely-available 2017 review that placed this study in context and provided further details from other studies:

http://www.nature.com/tp/journal/v7/n5/full/tp201778a.html “Epigenetic and transgenerational mechanisms in infection-mediated neurodevelopmental disorders”

Experience-induced transgenerational programming of neuronal structure and functions

The second paper of Transgenerational epigenetic inheritance week was a 2017 German/Israeli review focused on:

“The inter- and transgenerational effects of stress experience prior to and during gestation..the concept of stress-induced (re-)programming in more detail by highlighting epigenetic mechanisms and particularly those affecting the development of monoaminergic transmitter systems, which constitute the brain’s reward system.

We offer some perspectives on the development of protective and therapeutic interventions in cognitive and emotional disturbances resulting from preconception and prenatal stress.”

The reviewers noted that human studies have difficulties predicting adult responses to stress that are based on gene expression and early life experience. Clinical studies that experimentally manipulate the type, level and timing of the stressful exposure aren’t possible. Clinical studies are also predicated on the symptoms being recognized as disorders and/or diseases.

The researchers noted difficulties in human interventions and treatments. Before and during pregnancy, and perinatal periods are where stress effects are largest. But current human research hasn’t gathered sufficient findings to develop practical guidelines for early intervention programs.


I’m not persuaded by arguments that cite the difficulties of performing human research on transgenerational epigenetic inheritance. There are overwhelming numbers of people who have obvious stress symptoms: these didn’t develop in a vacuum.

Researchers:

  • Design human studies to test what’s known from transgenerational epigenetic inheritance animal studies that will include documenting the subjects’ detailed histories with sufficient biometric samples and data obtained from their lineage.
  • Induce pregnant subjects to at least temporarily avoid what’s harmful for them and/or the offspring, in favor of what’s beneficial.
  • Document the subjects’ actions with history and samples.

I acknowledge that economic incentives may not be enough to get people to participate. I’m familiar with a juvenile sickle-cell study that didn’t get enough subjects despite offering free transportation and hundreds of dollars to the caregivers per visit. The main problem seemed to be that the additional income would be reported and threaten the caregivers’ welfare benefits.

Stop whining that your jobs are difficult, researchers. Society doesn’t owe you a job. EARN IT – get yourself and the people in your organization motivated to advance science!

http://www.sciencedirect.com/science/article/pii/S014976341630731X “Experience-induced transgenerational (re-)programming of neuronal structure and functions: Impact of stress prior and during pregnancy” (not freely available)

Does living near a forest keep your amygdala healthier?

A thought-provoking post from A Paper a Day Keeps the Scientist Okay entitled “Living Near a Forest Keeps Your Amygdala Healthier” referenced a 2017 German human study which found:

“..a relationship between place of residence and brain health: those city dwellers living close to a forest were more likely to show indications of a physiologically healthy amygdala structure and were therefore presumably better able to cope with stress.”

The researchers accomplished the imperative of meeting the study’s stated objective:

“We set out to identify and characterize the geographical elements of a city that are associated with these brain structures following a suggestion by Kennedy and Adolph that studies should begin to derive recommendations for urban planning and architecture.

The results of our study may suggest that forests in and around the cities are a valuable resource that should be promoted. However future longitudinal studies are needed to investigate the causal directionality of the effect in order to disentangle whether more forest in ones habitat facilitates brain structural integrity or potentially those people with better brain structural integrity choose to live closer to forests. Moreover we need to investigate whether living close to the forest is associated with an absence of risk factors such as noise, air pollution or stress and thereby has beneficial effects or whether the forest itself constitutes a salutary factor that promotes well-being.”

https://www.nature.com/articles/s41598-017-12046-7 “In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure”


A major limitation of this study’s methodology was intentional non-use of an available data source. Referring to Do we need to study the brain to understand the mind? posted earlier this week:

“Self-report is still the gold standard for assessing emotional experience and the contents of thought. Isn’t it easier just to ask?”

These researchers put the forest before the trees, and designed a study that didn’t ask subjects important questions such as why they lived where they lived. The researchers inferred sketchy fMRI-geography associations because they didn’t solicit relevant primary information via individual self-reports.


I don’t live in Berlin, and I’m not part of the selected cohort, but I otherwise generally meet this study’s subject parameters. Something in my past causes me to actively select housing that isn’t in a noisy environment. If I were asked why I lived where I lived, my answer would have included:

  • A deciding factor in why I sold my second house was traffic noise in wintertime;
  • A deciding factor in why I bought my fourth house was its location in the housing development’s center, away from street noise; and
  • A deciding factor in why I live where I now live is the house’s orientation away from both direct and reflective traffic noise sources.

Processing my hypothetical fMRI data with my self-reported historical housing choices may or may not have found:

“Geographical features in the proximal participants’ habitat are associated with brain integrity.”

Using better-quality information of self-reports, though, it’s unlikely that an association this study would have found to be significant – a chance fact that I live within one kilometer of a forest – would have been deemed significant.

Do we need to study the brain to understand the mind?

A coauthor of the studies referenced in:

offered an opinion piece in A Paper a Day Keeps the Scientist Okay entitled “Do We Need To Study The Brain To Understand The Mind?”

“The emerging consensus appears to be that implementation is important. Interestingly, the inverse question is also being asked by neurobiologists—do we need consider the mind to understand the brain?—and answered largely and increasingly in the affirmative.

Is pain different from negative emotions such as sadness and anger, or are they variants on a common theme? Pain appears to be distinct from negative emotion, but commonalities suggest ways in which they may share underlying processes such as heightened attention.

One of the biggest pitfalls is the temptation to observe brain activity and make inferences about the psychological state—for example, to infer:

  • Episodic memory retrieval from hippocampal activity,
  • Fear from amygdala activity, or
  • Visual processing from activity in the ‘visual cortex.’

These inferences ignore the scope of processes which may activate each of these areas and involve a fallacy in reasoning: “if memory then hippocampus” is not the same thing as “if hippocampus then memory.”

The fact that few brain areas, including the ‘visual cortex,’ are dedicated to one process means that self-report is still the gold standard for assessing emotional experience and the contents of thought. This is a serious challenge for those who would like, for example, to assess your brand preferences or your political affiliation from a brain scan. (And isn’t it easier just to ask?)”

Epigenetic effects of early life stress exposure

This 2017 Netherlands review subject was the lasting epigenetic effects of early-life stress:

“Exposure to stress during critical periods in development can have severe long-term consequences.

One of the key stress response systems mediating these long-term effects of stress is the hypothalamic-pituitary-adrenal (HPA) axis.

Early life stress (ELS) exposure has been reported to have numerous consequences on HPA-axis function in adulthood.

ELS is able to “imprint” or “program” an organism’s neuroendocrine, neural and behavioral responses to stress. Research focuses along two complementary lines:

  1. ELS during critical stages in brain maturation may disrupt specific developmental processes (by altered neurotransmitter exposure, gene transcription, or neuronal differentiation), leading to aberrant neural circuit function throughout life.
  2. ELS may induce modifications of the epigenome which lastingly affect brain function.

These epigenetic modifications are inducible, stable, and yet reversible, constituting an important emerging mechanism by which transient environmental stimuli can induce persistent changes in gene expression and ultimately behavior.”


In early life, the lower brain and limbic system brain structures are more developed and dominant, whereas the cerebrum is less developed (use the above rodent graphic as a rough guide). Stress and pain generally have a greater impact on a fetus than an infant, and a greater impact on an infant than an adult.

The reviewers cited 50+ studies from years 2000-2015 in the “Early Life Stress Effects in a “Matching” Stressful Adult Environment” section to argue for the match / mismatch theory:

“Encountering ELS prepares an organism for similar (“matching”) adversities during adulthood, while a mismatching environment results in an increased susceptibility to psychopathology, indicating that ELS can exert either beneficial or disadvantageous effects depending on the environmental context.

Initial evidence for HPA-axis hypo-reactivity is observed for early social deprivation, potentially reflecting the abnormal HPA-axis function as observed in post-traumatic stress disorder.

Experiencing additional (chronic) stress in adulthood seems to normalize these alterations in HPA-axis function, supporting the match / mismatch theory.”

Evidence for this theory was contrasted with the allostatic load theory presented in How one person’s paradigms regarding stress and epigenetics impedes relevant research.


The review mainly cited evidence from rodent studies that mismatched reactions in adulthood may be consequences of early-life events. These events:

“Imprint or program an organism’s neuroendocrine, neural and behavioral responses..leading to aberrant neural circuit function throughout life..which lastingly affect brain function.”

Taking this research to a personal level:

  • Have you had feelings that you were unsafe, although your environment was objectively safe?
  • Have you felt uneasy when people are nice to you?
  • Have you felt anxious when someone pays attention to you, even after you’ve acted to gain their attention?

Mismatched human feelings are one form of mismatched reactions. These may be consequences of early-life experiences, and indicators of personal truths.

If researchers can let go of their biases and Advance science by including emotion in research, they may find that human subjects’ feelings produce better evidence for what actually happened during the subjects’ early lives than do standard scientific methods of:

Incorporating feeling evidence may bring researchers and each individual closer to discovering the major insults that knocked their development processes out of normally robust pathways and/or induced “persistent changes in gene expression and ultimately behavior.”

https://www.frontiersin.org/articles/10.3389/fncel.2017.00087/full “Modulation of the Hypothalamic-Pituitary-Adrenal Axis by Early Life Stress Exposure”


I came across this review as a result of it being cited in http://www.sciencedirect.com/science/article/pii/S1084952117302884 “Long-term effects of early environment on the brain: Lesson from rodent models” (not freely available)

Epigenetic effects of THC differ between female adolescents and adults

This 2017 Italian rodent study found:

“THC [delta9-tetrahydrocannabinol, the psychoactive compound of cannabis] exposure affects histone modifications in the brain of female rats in a region- and age-specific manner. Specifically, THC acts on different targets depending on the considered brain area and, remarkably, the adolescent brain is generally more sensitive to THC than the adult brain.

Adolescent exposure to THC, or to synthetic cannabinoids, induced sex-dependent brain and behavioral alterations at adulthood. In female rats, the phenotype was more complex, as both depressive-like and psychotic-like signs were present.

Development of the depressive/psychotic-like phenotype is restricted to adolescent THC exposure. Not only the behavioral phenotype developed after adolescent, and not adult, exposure, but also changes in both histone modifications and gene expression were more widespread and intense after adolescent treatment, further confirming a specific adolescent susceptibility.

The primary effect in the adolescent brain was represented by changes leading to transcriptional repression, whereas the one observed after adult treatment led to transcriptional activation. Moreover, only in the adolescent brain, the primary effect was followed by a homeostatic response to counterbalance the THC-induced repressive effect, except in the amygdala.”

The authors’ interpretation of the brain area results was:

“The amygdala is more responsive in adult than adolescent animals. Since it has been established that the amygdala is activated during exposure to aversive stimuli, functioning as a “behavioral brake”, different response between adult and adolescent animals could represent the biological bases of the adolescent propensity for risk-taking and novelty-seeking behaviors. Also in adolescent humans, neuroimaging studies have shown a weaker involvement of the amygdala, and a greater contribution of the NAc [nucleus accumbens], in response to negative and positive stimuli compared to adults.”

http://www.mdpi.com/1422-0067/18/10/2094 “Chronic Δ9-THC Exposure Differently Affects Histone Modifications in the Adolescent and Adult Rat Brain”

A study of perinatal malnutrition where the paradigm excluded epigenetic inheritance

This 2017 New York/Swedish rodent study subject was the epigenetic effects on the F1 children of maternal low protein diet during pregnancy and lactation:

“Male, but not female, offspring of LPD [low protein diet] mothers consistently displayed anxiety– and depression-like behaviors under acute stress.

Our proposed pathway connecting early malnutrition, sex-independent regulatory changes in Egr1 [an Early growth response gene], and sex-specific epigenetic reprogramming of its effector gene, Npy1r [neuropeptide Y receptor Y1 gene], represents the first molecular evidence of how early life risk factors may generate sex-specific epigenetic effects relevant for mental disorders.”


The study was purposely incomplete regarding transgenerational epigenetic effects that may be transmitted from the F1 children to their F2 grandchildren and F3 great-grandchildren. Similar to How one person’s paradigms regarding stress and epigenetics impedes relevant research, the paradigm continued by one of this study’s coauthors restricted inquiry into epigenetic inheritance.

How can the other coauthors respond when a controller of funding publishes the paper referenced in What is epigenetic inheritance? and otherwise makes his narrow views regarding epigenetic inheritance well-known? If the controller’s restricted views won’t allow the funding scope to extend testing to study F2 grandchildren and F3 great-grandchildren, the experiments end, and our understanding of epigenetic inheritance isn’t advanced.

This purposely incomplete study showed that the coauthor only gave lip service to advancing science when he made statements like:

“Further work is needed to understand whether and to what extent true epigenetic inheritance of stress vulnerability adds to the well-established and powerful influence of genetics and environmental exposures.”

The papers of Transgenerational epigenetic inheritance week show the spectrum of opportunities to advance science that were intentionally missed.

https://www.nature.com/articles/s41598-017-10803-2 “Perinatal Malnutrition Leads to Sexually Dimorphic Behavioral Responses with Associated Epigenetic Changes in the Mouse Brain”

How one person’s paradigms regarding stress and epigenetics impedes relevant research

This 2017 review laid out the tired, old, restrictive guidelines by which current US research on the epigenetic effects of stress is funded. The reviewer rehashed paradigms circumscribed by his authoritative position in guiding funding, and called for more government funding to support and extend his reach.

The reviewer won’t change his beliefs regarding individual differences and allostatic load pictured above since he helped to start those memes. US researchers with study hypotheses that would develop evidence beyond such memes may have difficulties finding funding except outside of his sphere of influence.


Here’s one example of the reviewer’s restrictive views taken from the Conclusion section:

Adverse experiences and environments cause problems over the life course in which there is no such thing as “reversibility” (i.e., “rolling the clock back”) but rather a change in trajectory [10] in keeping with the original definition of epigenetics [132] as the emergence of characteristics not previously evident or even predictable from an earlier developmental stage. By the same token, we mean “redirection” instead of “reversibility”—in that changes in the social and physical environment on both a societal and a personal level can alter a negative trajectory in a more positive direction.”

What would happen if US researchers proposed tests of his “there is no such thing as reversibility” axiom? To secure funding, the prospective studies’ experiments would be steered toward altering “a negative trajectory in a more positive direction” instead.

An example of this influence may be found in the press release of Familiar stress opens up an epigenetic window of neural plasticity where the lead researcher stated a goal of:

“Not to ‘roll back the clock’ but rather to change the trajectory of such brain plasticity toward more positive directions.”

I found nothing in citation [10] (of which the reviewer is a coauthor) where the rodent study researchers even attempted to directly reverse the epigenetic changes! The researchers under his guidance simply asserted:

“A history of stress exposure can permanently alter gene expression patterns in the hippocampus and the behavioral response to a novel stressor”

without making any therapeutic efforts to test the permanence assumption!

Never mind that researchers outside the reviewer’s sphere of influence have done exactly that, reverse both gene expression patterns and behavioral responses!!

In any event, citation [10] didn’t support an “there is no such thing as reversibility” axiom.

The reviewer also implied that humans respond just like lab rats and can be treated as such. Notice that the above graphic conflated rodent and human behaviors. Further examples of this inappropriate rodent / human merger of behaviors are in the Conclusion section.


What may be a more promising research approach to human treatments of the epigenetic effects of stress? As pointed out in The current paradigm of child abuse limits pre-childhood causal research:

“If the current paradigm encouraged research into treatment of causes, there would probably already be plenty of evidence to demonstrate that directly reducing the source of the damage would also reverse damaging effects. There would have been enough studies done so that the generalized question of reversibility wouldn’t be asked.

Aren’t people interested in human treatments of originating causes so that their various symptoms don’t keep bubbling up? Why wouldn’t research paradigms be aligned accordingly?”

http://journals.sagepub.com/doi/full/10.1177/2470547017692328 “Neurobiological and Systemic Effects of Chronic Stress”