Critical period

The thalamus part of the limbic system has a critical period for connections

gettingwell4 2-3 stars Required further work, Anterior cingulate cortex, Brain development, Cerebrum, Limbic system, Lower brain, Primal Therapy, Thalamus , , ,

This highly-jargoned 2015 UK study found that connections made by the thalamus of the developing human fetus had a critical period of the last trimester of womb-life. Babies born before the 33rd week of gestation experienced thalamic disconnections compared with normal-term babies and adults. The disconnections increased with a shorter womb-life.

The thalamus of premature babies also developed stronger connections with areas of the face, lips, tongue, jaw, and throat. They presumably needed these connections for survival actions such as breathing and feeding that aren’t a part of the last trimester of womb-life.

The study confirmed that the structures of thalamic connections of normal-term babies were very similar to those of adults. The study added to the research that shows that human limbic systems and lower brains closely approximate their lifelong functionalities at the normal time of birth.

It was difficult to measure the thalamus at this stage of life with current technology, and the researchers had to discard over two-thirds of their results. The researchers recommended monitoring these premature babies for difficulties in later childhood that may be caused by their early-life experiences.

Why would this monitoring recommendation apply to just the study’s subjects? We know from other studies that a main purpose of thalamic connections is to actively control and gate information to and from the cerebrum.

Would it make sense for a medical professional to disregard any patient’s birth history if they had problems in their brain’s gating functions or connectivity?

One researcher said:

“The ability of modern science to image the connections in the brain would have been inconceivable just a few years ago, but we are now able to observe brain development in babies as they grow, and this is likely to produce remarkable benefits for medicine.”

This study’s results provided evidence for a principle of Dr. Arthur Janov’s Primal Therapy: the bases for disconnection from aspects of oneself are often set down during gestation. The “remarkable benefits for medicine” are more likely to be along the lines of what I describe in my Scientific evidence page.

http://www.pnas.org/content/112/20/6485.full “Specialization and integration of functional thalamocortical connectivity in the human infant”

Can a Romanian orphan give informed consent to be an experimental subject?

gettingwell4 < 0 Detracted from science, Amygdala, Brain development, Cerebrum, Cortisol, Hypothalamus, Limbic system, Neurochemicals, Stress , ,

This 2015 study used Romanian orphans as lab rats for findings of which I failed to see the value. The world didn’t really need any further research to demonstrate that foster care would be better for a child than staying in an orphanage.

The researchers placed the orphans in five separate stressful situations, and measured their cortisol and DHEA-S levels, along with their electrocardiograph and impedance cardiograph activity. The findings were:

“Children who were removed from the Romanian institutions and placed with foster parents before the age of 24 months had stress system responses similar to those of children being raised by families in the community.

The children raised in institutions showed blunted responses in the sympathetic nervous system, associated with the flight or fight response, and in the HPA axis, which regulates cortisol.”

One unsupported assertion from the researchers was:

“We provide evidence for a causal link between the early caregiving environment and stress response system reactivity in humans with effects that differ markedly from those observed in rodent models.”

The researchers stated that rodent studies have converged to find:

“Early-life adversity results in hyperreactivity of the sympathetic nervous system (SNS) and hypothalamic–pituitary–adrenal (HPA) axis.”

It’s baloney that the same results from early life adversity in rodents haven’t also been present in humans. Even the lead researcher herself said in a news article:

“More significantly, McLaughlin said, their [the orphans] stress response systems might have been initially hyperactive at earlier points in development, then adapted to high levels of stress hormones.”

The difference was that the rodents were monitored 24/7 until researchers killed and dissected them. The children’s periods of adversity likely started while in the womb, and their lives had been monitored for research purposes sporadically after their births.

Everybody knows that just because adverse events and effects in these children’s lives weren’t recorded by researchers didn’t mean these effects weren’t present at some point.

Particularly irksome was another unsupported assertion from the lead reviewer:

“The children involved in the study are now about 16 years old, and researchers next plan to investigate whether puberty has an impact on their stress responses. It could have a positive effect, McLaughlin said, since puberty might represent another sensitive period when stress response systems are particularly tuned to environmental inputs. “It’s possible that the environment during that period could reverse the impacts of early adversity on the system,” she said.”

No, this is NOT possible. We may as well expect an apple to fall upward.

The impacts of early adversity persist with enduring physiological changes as shown in experimental studies. Studies have NOT provided evidence that the subjects’ environment can cause the effects of complete reversal of all these changes, no matter the stage of life of the subjects.

This point was addressed in The effects of early-life stress are permanent alterations in the child’s brain circuitry and function rodent study:

“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.”

That study had the same reviewer as the current study. The current study’s lead researcher knew or should have known of this and other relevant research. She knew or should have known of the irreversibility of critical periods, during which developments either occurred or were forever missed.

Did the lead researcher make assertions not supported by the study or relevant research – assertions made counter to her scientific knowledge – show her unease about treating the orphans as lab rats? Was there was some other agenda in play?

The larger problem was the study’s informed consent with this group of Romanian orphans. If you were in contact with a damaged person, and implicitly gave them hope that you would improve their life, then who are you as a feeling human being when you don’t personally carry through? Does the legal documentation matter?

Also, I’ve noticed problems with several studies that had this particular reviewer:

Add the current study to the list.

http://www.pnas.org/content/112/18/5637.full “Causal effects of the early caregiving environment on development of stress response systems in children”

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.

Would you deprive your infant in order to be in a researcher’s control group?

gettingwell4 2-3 stars Required further work, Brain development, Cerebrum, Epigenetics , , , ,

This 2015 Harvard study found that exposing extremely premature babies to sounds of their mothers enlarged their auditory cortex.

The lead researcher stated:

“Our findings do not prove that the brains of these babies are necessarily better, and we cannot conclude that they will end up with no developmental disabilities.

We don’t know the advantages of having a bigger auditory cortex.”

It’s too bad that studies like this one have to take deprived infants and further deprive them for use as a control group. I suppose it’s possible that the control group members’ development could just be shifted, similar to the Maternal depression and antidepressants epigenetically change infant language development study.

However, given the findings of the Our early experiences are maintained and unconsciously influence us for years, if not indefinitely study, it’s also possible that the last trimester of womb life is a critical period for a child’s auditory cortex. If timely development doesn’t take place within the environment provided by the mother, there may not be another period to fully catch up on growth and learning, even given the effects of neural plasticity.

http://www.pnas.org/content/112/10/3152.full “Mother’s voice and heartbeat sounds elicit auditory plasticity in the human brain before full gestation”

Do the impacts of early experiences of hunger affect our behavior, thoughts, and feelings today?

gettingwell4 5+ stars Premium, Epigenetics, Primal Therapy , , , , , , ,

This 2015 worldwide human study Hunger promotes acquisition of nonfood objects found that people’s current degree of hungriness affected their propensity to acquire nonfood items.

The researchers admitted that they didn’t demonstrate cause and effect with the five experiments they performed, although the findings had merit. News articles poked good-natured fun at the findings with headlines such as “Why Hungry People Want More Binder Clips.”

The research caught my eye with these statements:

“Hunger’s influence extends beyond food consumption to the acquisition of nonfood items that cannot satisfy the underlying need.

We conclude that a basic biologically based motivation can affect substantively unrelated behaviors that cannot satisfy the motivation.”

The concept of the quotes relates to a principle of Dr. Arthur Janov’s Primal Therapy – symbolic satisfaction of needs.

I stated two fundamentals of Primal Therapy in An agenda-driven study on beliefs, smoking and addiction that found nothing of substance:

  1. The physiological impacts of our early unmet needs drive our behavior, thoughts, and feelings.
  2. The painful impacts of our unfulfilled needs impel us to be constantly vigilant for some way to fulfill them.

Corollary principles of Primal Therapy are:

  • Our present efforts to fulfill our early unmet needs will seldom be satisfying. It’s too late.
  • We acquire substitutes now for what we really needed back then.
  • Acquiring these symbols of our early unmet needs may, at best, temporarily satisfy derivative needs.

But the symbolic satisfaction of derived needs – the symptoms – never resolves the impacts of early unfulfilled needs – the motivating causes:

  • We repeat the acquisition behavior, and get caught in a circle of acting out our feelings and impulses driven by these conditions.
  • The unconscious act-outs become sources of misery both to us and to the people around us.

In his book “Primal Healing” Dr. Arthur Janov gives two examples of critical periods only during which early needs can be satisfied:

  1. Being touched in the first months of life is crucial to a child’s development. The lack of close contact after the age of 5 wouldn’t have the same effect.
  2. Conversely, the need for praise at 6 months of age may not be essential, but it’s crucial for children at age 5.

As this study’s finding showed, there’s every reason for us to want researchers to provide a factual blueprint of causes for our hunger sensation effects, such as “unrelated behaviors that cannot satisfy the motivation.”

Why not start with hunger research? Objectives of the research should include answering:

  • What enduring physiological changes occurred as a result of past hunger?
  • How do these changes affect the subjects’ present behaviors, thoughts, and feelings?

Hunger research that would likely provide causal evidence for the effect of why people acquire “items that cannot satisfy the underlying need” should include studying where to start the timelines for the impacts of hunger. The impacts would potentially go back at least to infancy when we were completely dependent on our caregivers.

Infants can’t get up to go to the refrigerator to satisfy their hunger. All a hungry infant can do is call attention to their need, and feel pain from the deprivation of their need.

Is infancy far back enough, though, to understand the beginnings of potential impacts of hunger? The Non-PC alert: Treating the mother’s obesity symptoms positively affects the post-surgery offspring study referenced an older study of how the hunger of mothers-to-be had lifelong ill effects for the fetuses they carried during the Dutch hunger winter of 1944. The exposed children had epigenetic DNA changes from their mothers’ starvation, which resulted in relative obesity compared with their unexposed siblings.

Our early experiences are maintained and unconsciously influence us for years, if not indefinitely

gettingwell4 4-5 stars Advanced knowledge, Brain development, Brain hemispheres, Memory , , , ,

This 2014 Montreal study provided more evidence of critical periods during human development:

“Clearly illustrates that early acquired information is maintained in the brain and that early experiences unconsciously influence neural processing for years, if not indefinitely.

We show that internationally adopted children (aged 9–17 years) from China, exposed exclusively to French since adoption (mean age of adoption, 12.8 mo), maintained neural representations of their birth language despite functionally losing that language and having no conscious recollection of it.

We show that neural representations are not overwritten and suggest a special status for language input obtained during the first year of development.”

YES! GIVE US MORE STUDIES LIKE THIS ONE!

http://www.pnas.org/content/111/48/17314.full “Mapping the unconscious maintenance of a lost first language”