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Epigenetic DNA methylation and demethylation with the developing fetus

gettingwell4 5+ stars Premium, Brain development, Cortisol, Epigenetics, Hypothalamus, Limbic system, Neurochemicals, Oxytocin, Serotonin , ,

This extremely dense and informative 2014 UK summary study provided details about genomic imprinting:

“An unusual epigenetic process in that it is heritable and results in autosomal gene expression according to parent of origin.”

Several notes of interest:

  • Figure 3 had a fascinating sketch of how the fetus caused the mother’s hypothalamus to:

    “Determine forward maternal planning by directing/orchestrating maternal physiology and postnatal maternalism to synchronize with development of the fetus.”

  • Figure 4 followed up with a flowchart of how – with a female fetus – coexistence of three matrilineal generations in the pregnant female (her, the fetus, and the grandmother’s influence on the developing fetus’ ovarian oocytes) enabled intergenerational forward planning.
  • The study briefly noted significance of genomic imprinting on male sexual behavior, where, if processes didn’t proceed normally at this early stage of a male fetus’ development, could result in suboptimal adult behavior that didn’t change with experience.

F4.large

I’ll quote a few other unrelated passages that caught my eye.

“Reproductive success of mammals also places a considerable burden on matrilineal time and energy, with some 95% of mammalian female adult life committed to pregnancy, lactation, and maternal care.

Offspring that receive optimal nourishment and improved maternal care will be predisposed to develop a hypothalamus that is both genetically and epigenetically predisposed to this same type of good mothering.

The fetus controls its own destiny in times of acute starvation, especially in the last trimester of pregnancy, by short-term sacrifice of its placenta to preserve resources critical for brain development.”

http://www.pnas.org/content/112/22/6834.full “Genomic imprinting, action, and interaction of maternal and fetal genomes”

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.

Why do we cut short our decision-making process?

gettingwell4 5+ stars Premium, Beliefs, Cerebrum, Dopamine, Limbic system, Memory, Neurochemicals, Serotonin , , ,

This 2014 Zurich study found that people adapt their goal-directed decision-making processes in certain ways.

First, the researchers found that the subjects usually acted as though the computational cost of evaluating all outcomes became too high once the process expanded to three or more levels. Their approach to a goal involved developing subgoals. For example, for a three-level goal:

“Level 3 was most frequently decomposed into a tree of depth 2 followed by a depth-1 tree.”

A level 3 tree had 24 potential outcomes (24 outcomes = 3*2x2x2) whereas a level 2 tree followed by a level 1 tree had 10 potential outcomes (10 outcomes = 2*2×2 + 1*2).

Second, the subjects memorized and reused subgoals after their initial formation. The researchers found that this practice didn’t produce results significantly different than the optimal solutions, but that could have been due to the study’s particular design. The design also ensured that the subjects’ use of subgoals wasn’t influenced by rewards.

Further:

“It is known that nonhuman primate choices, for instance, depend substantially on their own past choices, above and beyond the rewards associated with the decisions. Similar arguments have been made for human choices in a variety of tasks and settings and have been argued to be under dopaminergic and serotonergic control.”

Third, ALL 37 subjects were unwilling to evaluate decisions that had initial large losses, even if they could see that the path to reach the optimal solution went through this loss outcome! The researchers termed this behavior “pruning” and stated:

“Pruning is a Pavlovian and reflexive response to aversive outcomes.”

The lead author relied on a previous study he coauthored to elaborate on the third finding. One statement in the previous study was:

“This theory predicts excessive pruning to occur in subjects at risk for depression, and reduced pruning to occur during a depressive episode.”

The current study’s subjects were screened out for depressive conditions, though. They were somewhat conditioned by the study design, but not to the extent where their behavior could be characterized as Pavlovian responses.

Fourth, the subjects’ use of larger subgoals wasn’t correlated to their verbal IQ.

So, what can we make of this research?

  1. Are shortcuts to our decision processes strictly a cerebral exercise per the first and second findings?
  2. Do we recycle our decision shortcuts like our primate relatives, uninfluenced by current rewards?
  3. Or is it rewarding to just not fully evaluate all of our alternatives?
  4. Do all of us always back away from decisions involving an initial painful loss, even when we may see the possibility of gaining a better outcome by persevering through the loss?
  5. Is it true that we excessively cut decision processes too short – such that many of our decisions are suboptimal – when we’re on our way to becoming depressed?
  6. Are we overwhelmed when depressed such that we don’t summon up the effort to cut short or otherwise evaluate decisional input?

Let me know your point of view.

http://www.pnas.org/content/112/10/3098.full “Interplay of approximate planning strategies”

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

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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.

Task performance and beliefs about task responses are solely cerebral exercises

gettingwell4 5+ stars Premium, Beliefs, Cerebrum, Limbic system

This 2013 human study provided details of which areas of the cerebrum participated in objective performance of a task vs. the subjects’ subjective confidence in their task responses:

“These results suggest the existence of functional brain networks indexing objective performance and accuracy of subjective beliefs distinctively expressed in a set of stable mental states.”

The subjects’ limbic systems were monitored during the fMRI and subsequent reporting, but the subjects’ limbic system areas weren’t activated during any of the experiments.

The researchers demonstrated that both task participation and subjective beliefs about the tasks were only cerebral exercises.

These findings should inform studies such as:

to neither characterize subjects’ task responses as “positive feelings” nor to ascribe emotions such as happiness to the subjects’ cerebral exercises.

http://www.pnas.org/content/110/28/11577.full “Distinct patterns of functional brain connectivity correlate with objective performance and subjective beliefs”

Thalamus gating and control of the limbic system and cerebrum is a form of memory

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This 2014 German rodent study showed how the thalamus actively controlled and gated information to and from the cerebrum.

The researchers elaborated in news coverage on how thalamic control and gating represented a form of memory:

“Q. When asked if, given that

  1. Sensory signals en route to the cortex undergo profound signal transformations in the thalamus,
  2. A key thalamic transformation is sensory adaptation in which neural output adjusts to statistics and dynamics of past stimuli, and
  3. The thalamus, hypothalamus and hippocampus being part of the limbic system, might memory reconsolidation play a role in the cortico-thalamic pathway?

A. “It’s conceivable that the cortico-thalamic pathway is subject to long term plasticity,” Groh conjectures. “In fact, on a synaptic level, these inputs can change their strength and retain adjusted strengths for long periods. This process represents another – albeit much slower – form of adaptation which some interpret as memory.”

Q. Conversely, might the thalamic-cortical pathway affect memory?

A. “If particular sensory-evoked activity patterns would cause long-term changes in the cortico-thalamic pathway, and thereby change the way incoming signals are processed before reaching the cortex,” he opines, “then this would indeed reflect a form of information storage.”

In other words, there are ways in addition to our usual ideas about memory that the limbic system remembers.

Other items in news coverage included:

“Rodents, cats, primates and humans show a common architecture of two feedback pathways from cortex to thalamus in the auditory, visual and somatosensory (but not olfactory) systems.

In this study we looked at processing of touch information, and we’d like to know how homologous pathways affect visual or auditory processing. It’s fascinating that despite fundamental differences between visual, auditory and somatosensory signals, basic layouts of thalamocortical systems for each modality are quite similar.”

Other areas of research that might benefit from their study include any medical research involving the thalamocortical system that might involve inappropriate gating of sensory signals.

For a given stimulus, output neural response will not be static, but will depend on recent stimulus and response history.”

http://www.pnas.org/content/111/18/6798.full “Cortical control of adaptation and sensory relay mode in the thalamus”

Emotional memories and out-of-body–induced hippocampal amnesia

gettingwell4 5+ stars Premium, Hippocampus, Limbic system, Memory, Stress

I was happy to see that the researchers in this 2014 Swedish human study included emotional memories when studying the hippocampus. They demonstrated that including emotional memories wasn’t that difficult to do.

In fact, this study’s researchers deemed emotional memories to be necessary in order to properly study the hippocampus, as evidenced by this statement about the experiment’s scripts:

“The selected life events had a moderate emotional level to ensure episodic long-term memory encoding.”

It made me wonder whether there are scientific bases for why other researchers go to such lengths to avoid including emotions in human memory studies.

Also:

“The experiments revealed two important findings. First, the behavioral results showed that episodic encoding of life events requires perceiving the world from the first-person perspective centered on one’s real body, and violations of this basic condition produced impaired episodic recall, indicative of fragmented encoding.

Second, the brain imaging data demonstrated that encoding events experienced out-of body specifically impacts the activation of the left posterior hippocampus during retrieval, suggesting an impaired hippocampal binding mechanism during encoding.

These findings are fundamentally important, as they suggest a link between the ongoing perceptual experiences of the body and the world from the first-person perspective and the hippocampal episodic memory system.”

To conclude:

“Given the apparent requirement of a natural first-person perspective between the body and the world for intact hippocampal memory function, a dissociative out-of-body experience during an acutely stressful event could, by itself, impair the encoding mechanism and produce fragmented, spatiotemporally disorganized memories.”

http://www.pnas.org/content/111/12/4421.full “Out-of-body–induced hippocampal amnesia”

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”

Our memories have contexts with specific places and times

gettingwell4 5+ stars Premium, Hippocampus, Limbic system, Memory

This 2014 rodent study was of the place aspect of a memory’s context. The researchers found that the CA3 segment of the hippocampus stored a unique representation of the location where the memory was formed:

“Place cells are hippocampal cells (in CA3) that fire specifically when the animal is at a certain location.

Form unique representations for every single environment.

When the animal was introduced to one of the rooms a second time the spatial map from the first exposure was reactivated.”

Our memories are formed within a specific context tied in the time aspect of a memory’s context:

“Hippocampal neurons not only track time, but do so only when specific contextual information (e.g., object identity/location) is cued.”

Our memories have contexts with specific places and times. Accessing a memory’s specific context would be a necessary part of accessing a full memory.

http://www.pnas.org/content/111/52/18428.full “Place cells in the hippocampus: Eleven maps for eleven rooms”