Cortisol

How to make a child less capable even before they are born: stress the pregnant mother-to-be

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

This 2014 rodent study showed how to make a less-capable pup by stressing the mother early in gestation. The study centered on a placental enzyme (OGT) that translates a mother’s stress into neuroprogramming of her developing fetus.

One finding was that this enzyme was less plentiful when the fetus was male compared with female.

Another finding was that the enzyme was less plentiful when the mother was stressed early in gestation, compared with unstressed mothers.

Informed by the first two findings, the researchers studied the placentae of male pups where the mother was stressed early in gestation. They found that these placentae had lower levels of an enzyme (Hsd17b3) that converts the precursor androstenedione into testosterone.

The resultant finding was that the male pups of stressed mothers had lower levels of testosterone than the control group of male pups.

A fourth finding was that offspring of both sexes born with a placenta where the OGT enzyme was less plentiful had 10-20% less body weight, a condition that developed after weaning. The researchers attributed this finding to reduced mitochondrial function in the hypothalamus compared with normal mice.

http://www.pnas.org/content/111/26/9639.full “Targeted placental deletion of OGT recapitulates the prenatal stress phenotype including hypothalamic mitochondrial dysfunction”

Are stress-induced epigenetic changes to DNA inherited across generations?

gettingwell4 0-1 star Wasted resources, Amygdala, Brain development, Cortisol, Epigenetics, Limbic system, Memory, Neurochemicals, Stress , , , , ,

This 2014 Geneva/Cambridge plant study ended by stating:

“The unequivocal demonstration of transgenerational transmission of environmentally-induced epigenetic traits remains a significant challenge.

One of the critical activities erasing stress memories is conserved between plants and mammals.”

However, the researchers didn’t demonstrate that their findings were broadly applicable for mammals or organisms other than the specific plant variety they studied. Possible reasons for these limited findings were given in a 2015 Australian study referenced by Mechanisms of stress memories in plants:

“The majority of DNA methylation analyses performed in plants to date have focused on Arabidopsis, despite being relatively depleted of TEs [transposable elements] (15–20% of the genome) and being poorly methylated compared to other plant genomes.

These studies have lacked the resolution to provide the specific context and genomic location of the changes in DNA methylation.”

There are also significant differences in how epigenetic inheritance across generations may operate among different species per Epigenetic reprogramming in plant and animal development.

Neither the current study nor the above review addressed the behavioral aspect of stress-induced epigenetic inheritance across generations. For example, the behavior of a mother whose DNA was epigenetically changed by stress can induce the same epigenetic changes to her child’s DNA when her child is stressed per One way that mothers cause fear and emotional trauma in their infants:

“Our results provide clues to understanding transmission of specific fears across generations and its dependence upon maternal induction of pups’ stress response paired with the cue to induce amygdala-dependent learning plasticity.”

http://www.pnas.org/content/111/23/8547.full “Identification of genes preventing transgenerational transmission of stress-induced epigenetic states”

Do researchers have to be cruel to our fellow primates to adequately research oxytocin?

gettingwell4 < 0 Detracted from science, Brain development, Cortisol, Limbic system, Neurochemicals, Oxytocin, Primal Therapy , ,

This 2014 primate study found:

“Oxytocin increased infants’ affiliative communicative gestures and decreased salivary cortisol, and higher oxytocin levels were associated with greater social interest.”

One would have to take an anti-evolutionist stance and believe that primates do not feel what humans feel to consider this process to NOT be cruel:

“To test these macaques, we took advantage of ongoing experiments requiring infants to be separated from their mother on the day of birth. Infants were nursery-reared, housed individually, with a cloth surrogate mother. They could see and hear other infants, but could not touch them.”

We know that primate infants, like humans, need “nourishment, transportation, warmth, protection, and socialization” from their mothers. What level of findings about oxytocin can a research study make that would justify this deprivation?

It surely wasn’t the findings this study made. We knew without doing the study that getting oxytocin from a nebulizer would be nowhere near an acceptable substitute for a mother’s touch and care.

http://www.pnas.org/content/111/19/6922.full “Inhaled oxytocin increases positive social behaviors in newborn macaques”

Chronic stress changes the architecture of the hippocampus, leading to depression and cognitive impairment

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

This 2014 rodent study gave further details that:

“Chronic stress, which can precipitate depression, induces changes in the architecture and plasticity of apical dendrites that are particularly evident in the CA3 region of the hippocampus.”

Other studies on the hippocampus CA3 region include:

http://www.pnas.org/content/111/45/16130.full “Role for NUP62 depletion and PYK2 redistribution in dendritic retraction resulting from chronic stress”

The brainstem nucleus locus coeruleus is the primary source of norepinephrine

gettingwell4 4-5 stars Advanced knowledge, Brainstem, Cerebrum, Cortisol, Locus coeruleus, Lower brain, Neurochemicals

This 2014 rodent study provided further information on the locus coeruleus segment of the brainstem:

“The brainstem nucleus locus coeruleus is the primary source of norepinephrine to the mammalian neocortex.

Neurons in the locus coeruleus maintain segregated connections to brain regions with distinctly different functions. Specifically, cells that communicate with the prefrontal cortex, a region involved in cognition and executive function, are characterized by properties that allow for independent and asynchronous modulation of operations in this area, compared with those that project to the motor cortex and regulate movement generation.”

http://www.pnas.org/content/111/18/6816.full “Heterogeneous organization of the locus coeruleus projections to prefrontal and motor cortices”

Stress impairs the normal matching of neuronal activity to increased blood flow in the amygdala

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Cortisol, Limbic system, Neurochemicals, Stress

This 2014 rodent study showed one aspect of how stress changed the amygdala. Stress didn’t allow normal matching of neuronal activity to increased blood flow:

“Chronic stress — which is a contributing factor for many diseases — impairs neurovascular coupling in the amygdala..

Neurovascular coupling (is) the process that matches neuronal activity with increased local blood flow.”

http://www.pnas.org/content/111/20/7462.full “Stress-induced glucocorticoid signaling remodels neurovascular coupling through impairment of cerebrovascular inwardly rectifying K+ channel function”

Active areas of the brain when making decisions in stressful conditions

gettingwell4 2-3 stars Required further work, Cerebrum, Cortisol, Limbic system, Lower brain, Memory, Neurochemicals, Stress

This 2013 human study was of decision making under stressful conditions.

Acute stress (ice water immersion) evoked habitual behavior rather than deliberative behavior. In my view, the subjects’ behaviors when under stress were driven more by their limbic system and lower brain areas than their cerebrum.

This finding wasn’t a big surprise. However, the researchers went on to state:

“Subjects with more executive resources to spare find themselves less susceptible to the behavioral changes brought about by stress response.”

I interpreted this statement to mean that when stressed, the more-capable subjects didn’t act out as much as the less-capable subjects acted out their respective feelings, instincts and impulses.

I felt that to understand this statement called for more investigation into the individual histories of the subjects:

  • What happened in their lives that enabled each person to acquire “more executive resources” or not?
  • What happened in their lives that made each person more or less sensitive to stress?
  • How are these two avenues of investigation related?

http://www.pnas.org/content/110/52/20941.full “Working-memory capacity protects model-based learning from stress”

The effects of early-life stress are permanent alterations in the child’s brain circuitry and function

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Brain development, Cortisol, Limbic system, Memory, Neurochemicals, Stress ,

The sobering application of this 2013 rodent study’s finding was that if the limbic systems of human children weren’t already permanently damaged before they entered an orphanage, the orphanage experience would probably do that to them:

“The current study manipulates the type and timing of a stressor and the specific task and age of testing to parallel early-life stress in humans reared in orphanages.

The results provide evidence of both early and persistent alterations in amygdala circuitry and function following early-life stress.

These effects are not reversed when the stressor is removed nor diminished with the development of prefrontal regulation regions.”

http://www.pnas.org/content/110/45/18274.full “Early-life stress has persistent effects on amygdala function and development in mice and humans”

One way that mothers cause fear and emotional trauma in their infants

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

This 2014 rodent study showed that infants learned to fear specific items in the environment that their mothers feared. The imprinting memory happened at a stage in the infants’ lives when they hadn’t yet developed the physiology to respond to the environment with fear on their own.

The learning cue was the mothers’ fear response – in this case, her distress odor, even when the mother was not present – coupled with the infants’ stress. The fear memory was stored in the infants’ amygdalae:

“These memories are acquired at younger ages compared with amygdala-dependent odor-shock conditioning and are more enduring following minimal conditioning.

Our results provide clues to understanding transmission of specific fears across generations and its dependence upon maternal induction of pups’ stress response paired with the cue to induce amygdala-dependent learning plasticity.”

There’s no scientific reason why this and related studies shouldn’t inform researchers who ignore the earliest stages of human life when studying limbic system disorders in humans.

For an example of researchers choosing to NOT be informed, look at Is this science, or a PC agenda? Problematic research on childhood maltreatment and its effects.

http://www.pnas.org/content/111/33/12222.full “Intergenerational transmission of emotional trauma through amygdala-dependent mother-to-infant transfer of specific fear”

How painful long-lasting memories are stored and why they are so strong

gettingwell4 2-3 stars Required further work, Amygdala, Cortisol, Limbic system, Memory, Neurochemicals, Stress , ,

This 2014 rodent study provided evidence for a portion of the neurophysiology that underlies how painful long-lasting memories are stored and why they are so strong. The amygdala was the brain area studied.

The researchers were misguided in news coverage by focusing on solutions such as external mechanisms to forget these memories. The researchers should think in terms of how their research can help people who can help themselves instead of having something externally done to them.

After all, we’re humans who can participate in therapy, not lab rats who need to be fixed.

http://www.pnas.org/content/111/51/E5584.full “Hebbian and neuromodulatory mechanisms interact to trigger associative memory formation”

Are 50 Shades of Grey behaviors learned in infancy?

gettingwell4 5+ stars Premium, Amygdala, Brain development, Cerebrum, Cortisol, Epigenetics, Hypothalamus, Limbic system, Lower brain, Memory, Neurochemicals, Primal Therapy, Serotonin, Stress , , , , , ,

Ever wonder how someone could become attached to their early childhood abuser?

Ever wonder what underlying neurobiological conditions may account for the popularity of Fifty Shades of Grey?

This 2014 rodent study “Enduring good memories of infant trauma” linked below showed how trauma changed infants’ limbic system and lower brains. As adults, they derived a neurochemical benefit from re-experiencing the traumatic conditions:

“Trauma and pain experienced in infancy clearly led to higher rates of adult rat depression-like behavior..(but) the infant brain has limited ability to link trauma to fear areas in the brain, such as the amygdala.

These results are surprising because cues associated with trauma experienced as adults provoke fear and do not rescue depressive behavior.

It is possible that giving SSRI medications to children could be detrimental to mental health in adulthood,” Dr. Sullivan says. “We believe that our research offers the first evidence for the impact of serotonin pathways.

The infant trauma increases serotonin to produce brain programming of later life depression, and the infant trauma cue increases serotonin to alleviate the adult depressive like symptoms.”

As the study may apply to humans, let’s say that as an infant, someone was traumatized by a caregiver who, for example, bound them too tightly and left them alone for too long. What adult behaviors and other symptoms may develop as results? The person may:

  • Show depression-like symptoms that would strangely be alleviated by being bound tightly and left alone for an extended period.
  • Develop attachments to people who treated them poorly in a way that triggered them to re-experience their early childhood traumas.
  • Feel their mood lift when their infancy traumas were cued.
  • Be unable to explain and integrate with their cerebrum what was going on with their limbic system and lower brains.
  • Be caught in a circle of acting out their feelings and impulses, with unfulfilling results.

Isn’t it curious that this acting-out behavior – driven by unconscious memories of traumatic conditions – is a subject for popular entertainment? It may have resonated with personal experiences of the people who read the books and watched the movie.

What about people who want to be relieved of their symptomatic behavior? Is it a justifiable practice:

  • To pass affected people over to talk therapies that aren’t interested in directly treating the cause – a neurobiological condition that exists in the limbic system and lower brains – only the symptoms?
  • To drug affected people with the neurochemicals that their condition makes scarce – the symptoms – instead of addressing the source?

A principle of Dr. Arthur Janov’s Primal Therapy is that people are capable of treating their own originating neurobiological conditions. One of the therapeutic results is that the patient is relieved of being caught in endless circles of acting-out behavior.

That way we can have our own lives, and not be driven by what happened during early stages of our lives.

http://www.pnas.org/content/112/3/881.full “Enduring good memories of infant trauma: Rescue of adult neurobehavioral deficits via amygdala serotonin and corticosterone interaction”

Shorter telomere length in older men but not older women

gettingwell4 2-3 stars Required further work, Cortisol, Immune system, Neurochemicals, Stress, Telomeres

This 2014 UK human study was the first on telomere length I’ve curated, so here’s some background information:

“Telomeres are..structures..that cap the ends of..chromosomes, protecting them from end-to-end fusion and degradation during cell division.

Human telomeric DNA naturally shortens with age during..cell divisions and as a result of oxidative attack.

At critical shortness, telomeres exhibit impaired function, leading to genomic instability, apoptosis, and cell senescence, often with altered transcriptional programming and mitochondrial dysfunction.

In humans, mutations that directly compromise telomere maintenance cause premature mortality and onset of a spectrum of diseases overlapping with the age-related diseases common in the population.

Shorter telomere length in white blood cells is linked and, in some cases, anticipates aging-related morbidity and mortality from conditions with immune system involvement, such as infectious diseases, cancer, and cardiovascular diseases, as well as risk factors, including hypertension, diabetes, obesity, and smoking.

A critical determinant of telomere length is the enzyme telomerase, which has the capacity to add..onto the..ends of telomeric DNA, extending telomere length and promoting genomic stability.

Acute mental stress appears to increase telomerase enzymatic activity at least transiently, and it has been suggested that high telomerase activity in conjunction with shorter telomere length may be indicative of a stressed system.”

The study put UK civil service men and women ages 54 through 76 through a series of stress tests. They found that men with longer telomeres had quicker recovery times than did men with shorter telomeres.

Men with shorter telomeres and low telomerase activity also had quicker recovery times than did men with shorter telomeres and high telomerase activity:

“In addition, we found that the (shorter telomeres and high telomerase activity men) had blunted reactivity to acute stress in diastolic blood pressure, heart rate, and cortisol.”

No telomere-based differences occurred with women:

“The explanation for the sex difference in response profiles in our study is not clear. Hormonal processes are unlikely to be directly responsible, because women in this study were postmenopausal.”

http://www.pnas.org/content/111/12/4519.full “Shorter telomeres with high telomerase activity are associated with raised allostatic load and impoverished psychosocial resources”