Control group

Inflexible behavior may be a byproduct of stress

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

This 2015 German human study found:

“15-mo-old infants exposed to stress thereafter kept performing a previously effective action, even after the action suddenly became ineffective.

Infants in a no-stress control group flexibly adjusted their behavior by disengaging from the newly ineffective action in favor of exploring an alternative action.

This finding demonstrates that stress impairs infants’ ability to adjust their behavior to changing circumstances.”

The primary measurement of stress levels was cortisol. Stressful conditions were:

  • A stranger sat down next to them;
  • A dancing robot played loud music and moved around;
  • The infant’s caregivers left the room for up to four minutes.

News coverage stated that the study’s design was an adaptation of experiments that produced the same findings in adults. But would adult humans be stressed by being left alone for four minutes?

It’s likely that animal studies were the basis for some of this study’s experiments, as in the If research provides evidence for the causes of stress-related disorders, why only focus on treating the symptoms? study:

“Maternal separation in rodents is a useful model of early-life stress that results in enduring physiological and behavioral changes that persist into adulthood.”

A study limitation was that it involved just 26 infants.

http://www.pnas.org/content/112/41/12882.full “Stress impairs cognitive flexibility in infants”

A study that provided evidence for basic principles of Primal Therapy

gettingwell4 5+ stars Premium, Cerebrum, Epigenetics, Glutamate, Hippocampus, Limbic system, Memory, Neurochemicals, Primal Therapy, Stress , , , , , ,

This 2015 Northwestern University rodent study found:

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

Memories formed in a particular mood, arousal or drug-induced state can best be retrieved when the brain is back in that state.

‘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 best way to access the memories in this system is to return the brain to the same state of consciousness as when the memory was encoded.”

The study demonstrated one method of activating neurobiological pathways with a drug to remove a hippocampal memory’s protection, which played a part in enabling subjects to relive their remembered experiences. This rodent study’s methods weren’t designed to therapeutically access similarly protected memories with humans.

From the Northwestern press release:

“There are two kinds of GABA [gamma-Aminobutyric acid] receptors. One kind, synaptic GABA receptors, works in tandem with glutamate receptors to balance the excitation of the brain in response to external events such as stress.

The other population, extra-synaptic GABA receptors, are independent agents.

If a traumatic event occurs when these extra-synaptic GABA receptors are activated, the memory of this event cannot be accessed unless these receptors are activated once again.

‘It’s an entirely different system even at the genetic and molecular level than the one that encodes normal memories,’ said lead study author Vladimir Jovasevic, who worked on the study when he was a postdoctoral fellow in Radulovic’s lab.

This different system is regulated by a small microRNA, miR-33, and may be the brain’s protective mechanism when an experience is overwhelmingly stressful.

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’d point out that “can’t remember” and “inaccessible traumatic memories” phrases used above were in reference to what’s usually called “memory” i.e., a recall initiated by the cerebrum.

The study’s findings should inform memory-study researchers if they care to understand how emotional memories can be formed and re-experienced.

The study provided evidence for fundamentals of Dr. Arthur Janov’s Primal Therapy, such as:

  • Experiences associated with pain can be remembered below our conscious awareness.
  • The retrieval and re-experiencing of emotional memories can engage our lower-level brain areas without our higher-level brain areas’ participation.

The obvious nature of this study’s straightforward experimental methods made me wonder why other researchers hadn’t used the same methods decades ago.

Use of this study’s methodology could have resulted in dozens of informative follow-on study variations by now, and subsequently found whether subjects’ physiological, behavioral, and epigenetic measurements differed from control group subjects, as in:

“miR-33 is downregulated in response to gaboxadol [the drug used to change subjects’ brain state] and modulates its effects on state-dependent fear.”

See Resiliency in stress responses for abstracts of three follow-on papers by these researchers.

http://www.nature.com/neuro/journal/v18/n9/full/nn.4084.html “GABAergic mechanisms regulated by miR-33 encode state-dependent fear”

MP3 with lead researcher Dr. Jelena Radulovic: http://www.thenakedscientists.com/HTML/specials/show/20150825/

Adverse effects of inflammation and stress on hippocampal synapses

gettingwell4 2-3 stars Required further work, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Stress , , ,

This dense and highly-jargoned 2015 rodent study found:

“The suppression of BDNF [brain-derived neurotrophic factor] signaling, LTP [long-term potentiation], and memory may be driven by an increased sensitivity to IL-1β [the proinflammatory cytokine interleukin 1β] that occurs directly at synapses.”

The researchers reversed the adverse effects of IL-1β after they induced stress and inflammation. Blocking IL-1β when there wasn’t stress or inflammation, however, also caused adverse effects:

“Interestingly, administration of AS1 [the compound that blocked the proinflammatory responses] in the absence of LPS [the bacterial compound used to stress the subjects’ immune systems] treatment also impaired OLM [the object location memory test where control group rodents exhibited a preference for a novel location over a familiar location].

This finding is consistent with the notion that endogenous IL-1β at physiologically low levels may be essential for hippocampal memory function.”

The researchers asserted:

“Our data reveal a previously unidentified mechanism that explains the age-related vulnerability of hippocampal function to impairment by inflammation.”

Instead of couching their findings with a non-causal “age-related” term, could the researchers have specifically identified causes?

“IL-1β activates different pathways via AcP (proinflammatory) or AcPb (prosurvival) IL-1 receptor subunits.

This study demonstrates that the IL-1 receptor subunit system undergoes an age-dependent reconfiguration in hippocampal synapses.

This previously undescribed reconfiguration, characterized by an increase in the AcP/AcPb ratio, is responsible for potentiating impairments of synaptic plasticity and memory by IL-1β.”

What were the underlying causes for the relatively increased AcP activation over AcPb activation? The researchers didn’t say. Their explanations were left hanging at a correlated-but-not-causal “age-dependent” level rather than a “mechanism that explains.”

http://www.pnas.org/content/112/36/E5078.full “Synapse-specific IL-1 receptor subunit reconfiguration augments vulnerability to IL-1β in the aged hippocampus”

DNA damage to fat cells may cause obesity and insulin resistance

gettingwell4 2-3 stars Required further work, Epigenetics, Stress ,

This 2015 Indiana rodent study found:

“DNA damage is a root cause of adipocyte senescence [fat cells that can no longer replicate], which plays a determining role in the development of obesity and insulin resistance.”

The researchers removed the capability for the subject mice to produce a protein that “plays an essential role in preventing cutaneous cancer caused by UV radiation-induced DNA damage.” They showed that this genetic deficiency:

“Causes obesity with visceral fat accumulation, hepatic steatosis, hyperleptinemia, hyperinsulinemia, and glucose intolerance.”

These researchers – in contrast with the Pulling on the chain of causes and effects with insulin resistance study – investigated causes for the various effects that included insulin resistance. However, the study’s applicability to humans wasn’t clear, since we most often develop symptoms such as insulin resistance due to causes other than genetics.

The study also demonstrated that treatment with a common dietary supplement – N-acetyl cysteine (NAC) – or metformin (Met):

“Reduce[d] adipose DNA damage.

Ameliorated cellular senescence and metabolic abnormalities.”

Body fat

High-fat and high-fructose diets caused the opposite effects in the subject genetic-deficient mice.

http://www.pnas.org/content/112/33/E4556.full “Ablation of XP-V gene causes adipose tissue senescence and metabolic abnormalities”

What’s an appropriate control group for a schizophrenia study?

gettingwell4 < 0 Detracted from science, Cerebrum ,

The researchers who did Our long-term memory usually selects what we pay closer visual attention to study were back zapping subjects’ brains again in this 2015 human study.

Prior to zapping subjects’ brains:

“In healthy individuals, these theta waves were steady and synchronized, but in people with schizophrenia, the waves were weak and disorganized, suggesting that they were having a harder time processing the mistake. And the subjects’ behavior bore that out—the healthy subjects slowed down by a few milliseconds when they made mistakes and did better in the next round, while the subjects with schizophrenia did not.”

Processing of an appropriate control group wasn’t clear to me from reading supplementary material. Subject patients were diagnosed with schizophrenia and took psychoactive medication which these researchers equated to chlorpromazine (Thorazine) dosages. Control group subjects had neither the condition nor were prescribed medications.

  • How did these researchers differentiate influences of psychoactive medications on experimental results from other influences on subjects’ conditions?
  • Were there numerical calculations not shown in supplementary material that somehow nullified effects of psychoactive medications?
  • To be sure that zapping was effective for subjects’ conditions, wouldn’t control group subjects need to take the same medications so that experimental data reflected only differences attributable to schizophrenia?

These researchers also asserted:

“Causal changes in the low-frequency oscillations improved behavioral responses to errors and long-range connectivity at the single-trial level.”

However, brain waves can’t be termed as base causes of human behavior. Studies such as:

clearly established that brain waves are effects of base causes.

http://www.pnas.org/content/112/30/9448.full “Synchronizing theta oscillations with direct-current stimulation strengthens adaptive control in the human brain”

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.

How brains mature during critical periods

gettingwell4 5+ stars Premium, Brain development, Epigenetics, Hippocampus, Limbic system , , , ,

This 2015 German rodent study found:

“Once silent synapses are consolidated in any neural circuit, initial experience-dependent functional optimization and critical periods end.

Silent synapses are thought to be immature, still-developing excitatory synapses.”

The number of silent synapses related to visual processing was measured at ~50% at eye opening. Visual experience reduced this to 5% or less by adulthood in the study’s control group. Removing a protein in the subjects’ hippocampus silenced the synapses back up to ~50%, even in adults.

Critical periods are:

“Characterized by the absolute requirement for experience in a restricted time window for neural network optimization.

Although some functions can be substantially ameliorated after the CP [critical period], they are rarely optimally restored.”

Two human studies were cited on critical periods in second-language and musical skills development, Sensitive periods in human development: Evidence from musical training (not freely available).

The researchers generalized their findings as:

“Experience-dependent unsilencing of silent synapses constitutes an important general maturational process during CPs of cortical development of different functional domains and suggest an interplay with inhibitory circuits in regulating plasticity.”

http://www.pnas.org/content/112/24/E3131.full “Progressive maturation of silent synapses governs the duration of a critical period”

The effects of inescapable, uncontrollable, repeated stress on the hippocampus

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Cerebrum, Cortisol, Epigenetics, Glutamate, Hippocampus, Limbic system, Neurochemicals, Stress , , ,

This 2015 MIT rodent study found:

“Behavioral stress impairs cognitive function via activation of a specific direct neural circuit from the basolateral amygdala to the dorsal hippocampus. Moreover, we delineate a molecular mechanism by which behavioral stress is translated to hippocampal dysfunction via a p25/Cdk5 (cyclin-dependent kinase 5)-dependent pathway and epigenetic alterations of neuroplasticity-related gene expression.”

The researchers made several intermediate findings to develop their main finding:

1. “Repeated stress is accompanied by

  • generation of p25,
  • up-regulation and phosphorylation of glucocorticoid receptors,
  • increased HDAC2 [the gene encoding the histone deacetylase 2 enzyme] expression, and
  • reduced expression of memory-related genes [most, but not all that were tested] in the hippocampus.”

2. “BLA [basolateral amygdala] activation is both necessary and sufficient for stress-associated molecular changes and memory impairments.”

3. “This effect [2. above] relies on direct glutamatergic projections from the BLA to the dorsal hippocampus.”

4. “p25 generation is necessary for the stress-induced memory dysfunction.”

From the Results section:

“Control mice showed a significant preference for the novel over the familiar object or location, whereas RFS [repetitive foot shock]-treated mice performed no better than chance.”

The subject adult mice underwent:

“Inescapable, uncontrollable repeated stress.”

Do humans also experience impaired “cognitive function” and “hippocampal dysfunction” and “epigenetic alterations of neuroplasticity-related gene expression” caused by “inescapable, uncontrollable repeated stress”?

And what are the real histories of people who aren’t curious, who don’t show “a significant preference for the novel over the familiar object or location”?

http://www.pnas.org/content/112/23/7291.full “Basolateral amygdala bidirectionally modulates stress-induced hippocampal learning and memory deficits through a p25/Cdk5-dependent pathway”

An inhibitory gene that affects alcohol binge behavior

gettingwell4 2-3 stars Required further work, Beliefs, Cerebrum, Dopamine, Limbic system, Lower brain, Neurochemicals, Thalamus , , ,

This 2015 La Jolla rodent study found that an inhibitory gene affected alcohol binging behavior:

“Our study reveals the behavioral impact of this cellular effect, whereby the level of GIRK3 [the gene] expression in the VTA [ventral tegmental area] tunes ethanol intake under binge-type conditions: the more GIRK3, the less ethanol drinking.”

GIRK3-silenced mice still binged, though, and got alcohol’s rewarding effects through dopamine’s other neural pathways.

High concentrations of the gene were found in the thalamus part of the limbic system of wild-type mice, the control group. Per the study’s title, this gene presumably contributes to the thalamus’ overall function of gating information from limbic system and lower brain areas to reach the cerebrum and vice versa.

And the potential causes for reduced GIRK3 expression are..?? Hopefully – someday – researchers will be focused on finding causes for abnormal gene expression rather than being content to just study effects of abnormal gene expression. Until then, the usual practice of considering only the effects led these researchers to:

“Believe that a compound selectively targeting GIRK3-containing channels may hold promise for reducing alcohol consumption in heavy binge drinkers.”

http://www.pnas.org/content/112/22/7091.full “GIRK3 gates activation of the mesolimbic dopaminergic pathway by ethanol”

Running a marathon, cortisol, depression, causes, effects, and agendas

gettingwell4 < 0 Detracted from science, Cerebrum, Cortisol, Limbic system, Lower brain, Memory, Neurochemicals, Stress , ,

Let’s imagine that you decide you want to run a marathon. You haven’t run in six months, and you know you’ll have to train.

On the first day of training, as you run your first mile a friend pops out of nowhere and says, “You’re sweating! That means you’re going up to Mile 14 today! Good job, you’re on your way!”

You may appreciate the encouragement, but would a friend’s assessment have anything to do with your physical reality? Before you’ve run one mile, can an observer of your sweat say with certainty that you’ll run 14 miles on your first day of training?

Yeah. That’s how I felt when reading this 2014 UK study that found:

“Adolescent boys who have high levels of stress hormone ‘cortisol’ along with some symptoms of depression are at a 14 times higher risk of the condition than their peers.”

The researchers latched onto teenagers (12-16 years old, mean 13.7) to assess a psychiatric condition. They stated that a physical effect as common as visible sweat was a biomarker that predicted where some of the teenagers were going with their lives.

The study’s only physical measurements were cortisol from saliva samples at 8:00 a.m. on four consecutive days, then repeated a year later. For comparison, a standard lab test is to measure cortisol from saliva taken four times in one day at 9:00 a.m., 1:00 p.m., 5:00 p.m., and 9:00 p.m.

Cortisol is an effect of multiple potential causes, including stress, which itself is often an effect of multiple potential causes. One common cause of stress and its cortisol byproduct is diet, for example, when a person consumes caffeine.

“Mean time between waking and morning-cortisol collection was 50 min.”

I found it hard to believe that teenagers who:

  • woke up at 7:10 a.m.,
  • gulped down who knows what for breakfast,
  • got ready for, and then
  • went to school for an 8:00 a.m. cortisol test

wouldn’t have relatively “elevated morning cortisol” from the resultant stress.

Subjects self-reported depressive symptoms via a 33-item questionnaire initially and again every four months. They were interviewed for psychiatric diagnoses.

The largest separator used for stratification within subjects was an autobiographic memory test. Without this test, the study wouldn’t have made its main finding, so let’s look at the test’s details:

“Anxious and depressed adolescent patients report significantly elevated levels of over-general categoric memories compared with well controls. Six positive and six negative words are presented on flashcards in pseudorandom order, and participants are instructed to recall a particular memory of an event in their life after each word. Sixty seconds were allowed for each response.

Responses were categorized as specific if they referred to an event with a specific time and place, lasting no longer than 1 d[ay]. Responses were considered overgeneral if they formed a general class of repeated events.”

We can see that the autobiographical memory test only considered the subjects’ verbal expressions – within a short time period – of their recalls of emotionally triggered memories. As informed by the principles described in Agenda-driven research on emotional memories, the recall of an emotional memory is a product of the cerebrum responding to input from limbic system and lower brain areas. When someone describes their recall of an emotionally triggered memory, it’s yet another level further removed from the brain areas that store emotional memories.

We can also see that test scores of the subjects’ verbal expressions aren’t capable of providing any etiologic evidence for an effect of high cortisol. A correlation is the best that could ever be shown by an autobiographic memory test. Again, the study’s main finding hinged on this third-order observational method of trying to figure out what’s going on inside subjects’ brains.

The researchers developed a control group, and made only a token attempt to trace the control group teenagers’ histories:

“The primary caregiver was interviewed about the quality of the family environment in three epochs (0–5, 6–11, and 12–14 y of age).

Four classes were found: optimal class, aberrant parenting, discordant, and hazardous.”

Were we supposed to believe that any primary caregiver would tell the truth about anything in a teenager’s history that indicated they had damaged their child? Good luck with that.

Anyway, the researchers didn’t act as though teenagers’ histories had any significant relationships with any present or future conditions. Their ahistoric biases showed by subsequently processing the entire history of each of the control group teenagers into a 1 or a 0 for the model.

The researchers then modeled this binary assessment to be relevant to the study’s main subjects!

The researchers’ agenda led to predetermined findings. Was the reviewer onboard with this agenda?

  • By disregarding the main subjects’ histories, it couldn’t provide etiologic evidence for any present or future effects.
  • By measuring only early morning cortisol, are we surprised that model numbers could be processed into some correlation?
  • Comparing this sole measurement to 325 measurements taken of subjects in Assessing a mountain climber’s condition without noticing their empty backpack made me wonder about the study designers’ real intentions.

News coverage of the study jumped on its flimsy finding to demand that something must be done. What did researchers offer teenagers who needed help?

  • After citing research that:

    “Showed null effects for two active treatments [cognitive behavioral therapy (CBT) and attentional training, respectively]”

    they recommended some unspecific:

    “New models of public mental health education and intervention in the youth population.”

  • After citing research that found:

    “Current diagnostic classifications [e.g., the Diagnostic and Statistical Manual for Mental Disorders (DSM) and the International Classification of Diseases (ICD)] have proved to have low diagnostic validity for investigations on the etiology, prevention, or treatment of MD [major depression]“

    the study relied on these diagnoses anyway, and then disclaimed:

    “It may also be the case that current classifications, as used in this study, such as DSM and ICD are simply not optimally specified.”

They didn’t make their case that “elevated morning cortisol” effect was an adequate biomarker for teenagers who needed help. They did a disservice to their subjects by neither investigating nor providing any etiologic evidence for observed effects.

Who really benefited from this underlying agenda? I didn’t see that it was teenagers who may have actually needed assistance.

Did the study’s funders know that these efforts had enormous lacks? And what did:

“New models of public mental health education and intervention in the youth population”

really mean?

http://www.pnas.org/content/111/9/3638.full “Elevated morning cortisol is a stratified population-level biomarker for major depression in boys only with high depressive symptoms”

Changing an individual’s future behavior even before they’re born

gettingwell4 5+ stars Premium, Brain development, Epigenetics, Stress , , , ,

This 2015 Harvard fruit fly research was a companion of the Is what’s true for a population what’s true for an individual? study.

The researchers began with the question:

“If we could rear genetically identical individuals from a variety of genetic backgrounds and rear them in the same environment, how much phenotypic variation between individuals of the same genotype would we see?”

They answered with:

“We show that different genotypes vary dramatically in their propensity for variability, that phenotypic variability itself, as a trait, can be heritable, and that loci affecting variability can be mapped.”

The specific problem that probably prompted this study was that the methodology of genome-wide association studies (GWAS) usually:

“Focuses on the average effect of alternative alleles averaged in a population.”

What this methodology often missed was:

“When phenotypic variation results from alleles that modify phenotypic variance rather than the mean, this link between genotype and phenotype will not be detected.”

The researchers altered the environment during a critical period of fruit flies’ development in order to induce epigenetic changes in the fruit fly pupae brains:

“Disruption of Ten-a [the synaptic target recognition gene Tenascin accessory] expression in midpupa affects behavioral variance [the standard statistical dispersion parameter].

In all cases, disrupting Ten-a increased the variability [the median of the absolute deviation from each observation’s median] in turning bias with no effect on the mean.”

I fully expect researchers to demonstrate that this finding has general applicability for humans, especially during womb-life. Research such as:

are steps in this direction just for one factor in the human fetal environment – stress. The effects of stressing a human fetus should be at least as significant as the effects produced on the study’s subjects with increased temperature during pupation.

http://www.pnas.org/content/112/21/6706.full “Behavioral idiosyncrasy reveals genetic control of phenotypic variability”

A mixed bag of findings about oxytocin, its receptor, and autism

gettingwell4 0-1 star Wasted resources, Epigenetics, Neurochemicals, Oxytocin ,

This 2014 Stanford human study found:

“No empirical support for the OXT [oxytocin] deficit hypothesis of ASD [autism spectrum disorder], nor did plasma OXT concentrations differ by sex, OXTR [oxytocin receptor] SNPs [single nucleotide polymorphisms], or their interactions.”

Apparently, there was a:

“Prevalent but not well-interrogated OXT deficit hypothesis of ASD.”

The researchers followed up this worthwhile finding with three weak findings. The first, as stated by one of the study’s lead researchers, was:

“It didn’t matter if you were a typically developing child, a sibling or an individual with autism: Your social ability was related to a certain extent to your oxytocin levels.”

The second weak finding was that, regarding OXTR SNPs:

“The minor allele of rs2254298 predicted global social impairments on the SRS [Social Responsiveness Scale] and diagnostic severity on the ADI-R [Autism Diagnostic Interview-Revised]. In contrast, the major allele of rs53576 predicted impaired affect recognition performance on the NEPSY [A Developmental NEuroPSYchological Assessment].”

This was at odds with other relevant research, leading the researchers to state:

“The functional significance of these two intronic variants remains unknown.”

The third weak finding irked me:

“Plasma OXT concentrations were highly heritable.”

because the researchers didn’t attempt to differentiate the contribution of the environment for the observed blood oxytocin levels, as did the similar How epigenetic DNA methylation of the oxytocin receptor gene affects the perception of anger and fear study.

I wonder what the reviewer’s feedback was about these weak findings. Did he make the researchers insert specific language into the lengthy paragraph about the study’s limitations, or did he give them a pass?

http://www.pnas.org/content/111/33/12258.full “Plasma oxytocin concentrations and OXTR polymorphisms predict social impairments in children with and without autism spectrum disorder”

People who donated a kidney to a stranger have a larger amygdala

gettingwell4 2-3 stars Required further work, Amygdala, Brain hemispheres, Cerebrum, Epigenetics, Limbic system ,

This 2014 Georgetown study was of people who had donated a kidney to a stranger. The study found that the subjects had a larger right amygdala part of their limbic systems:

“Our results support the possibility of a neural basis for extraordinary altruism.

In sum, our findings suggest that individuals who have performed an act of extraordinary altruism can be distinguished from healthy controls by increased right amygdala volume, as well as heightened responsiveness in right amygdala to fearful facial expressions, which may support enhanced recognition of these expressions.”

The researchers stopped short of causal explanations. They stated in the study’s abstract that:

“Individual variation in altruistic tendencies may be genetically mediated”

but didn’t develop any evidence to support this statement.

It would have been within the scope of the study had the researchers continued on to examine:

  • What may have happened in the subjects’ lives to possibly cause their neurobiological and psychological attributes?
  • What were the causes for the subjects’ extreme altruistic behavior?
  • Were these the same causes for their larger, more sensitive amygdala?

An accompanying PNAS commentary from a Harvard researcher made other points. However, the author showed his biases that the cerebrum rules human behavior with an out-of-left-field question at the end of a paragraph in which he developed specious reasoning.

The commentator was completely off base when he stated:

“Could it be that extraordinary altruists such as Maupin [a study participant] and the 19 individuals studied by Marsh et al. [the researchers] are special, not only because of how they feel when they see people in distress, but because of how they think?”

I don’t imagine that the brilliant commentator’s attempt to upstage the study’s subjects and put the spotlight on himself for some brilliant idea was much appreciated by anyone involved.

The amygdala is the central hub of a person’s limbic system. The study’s findings had very little to say about the subjects’ cerebral activity – thinking.

To postulate that the researchers missed that there was something different about the subjects’ thinking was out of touch with the realities of both the researchers’ scientific bases and the subjects. It’s another example of the current research mindset/social meme of cerebral dominance.

http://www.pnas.org/content/111/42/15036.full “Neural and cognitive characteristics of extraordinary altruists”

Kids who have a larger and better-connected hippocampus learn math better when tutored

gettingwell4 0-1 star Wasted resources, Brain development, Cerebrum, Hippocampus, Limbic system, Memory, Thalamus ,

This 2013 Stanford study of 24 eight- and nine-year-old children found that measurements of limbic system areas predicted how well the 11 boys and 13 girls would respond to 8 weeks of one-on-one math tutoring!

“Pretutoring hippocampal volume predicted performance improvements. Furthermore, pretutoring intrinsic functional connectivity of the hippocampus with dorsolateral and ventrolateral prefrontal cortices and the basal ganglia also predicted performance improvements.

Brain regions associated with learning and memory, and not regions typically involved in arithmetic processing, are strong predictors of responsiveness to math tutoring in children. More generally, our study suggests that quantitative measures of brain structure and intrinsic brain organization can provide a more sensitive marker of skill acquisition than behavioral measures.”

None of the assessments, such as IQ and working memory tests, predicted how much benefit a child would receive from one-on-one math tutoring. The 16 children in the control group who didn’t receive one-on-one math tutoring didn’t improve their math performance over the 8-week period. Adults use different brain areas when solving math problems.

Much of the news coverage was from vested interests who dismissed the findings. A typical headline was “Your child’s brain on math: Don’t bother?”

The No Child Left Behind people were concerned that science could predict that some children were better suited to math tutoring than others. Psychiatrists and psychologists responded with general dismissals like small sample size, and the journalist let that stand without asking them how they disagreed with any of the specific P-, T- and other values found in the study’s supplementary material.

The researchers were careful to invoke a politically-correct meme of “individual differences“ 19 times, including the study’s title!

“Individual differences” isn’t a causal explanation, however. The journalist whiffed and also gave a pass to the researchers on this uninformative-but-PC meme.

It certainly would have been within the scope of this study for the researchers to inquire further into causes for the findings. It possibly could have informed us of causal factors had the children’s test battery included emotional content, as did the subjects in the Early emotional experiences change our brains: Childhood maltreatment is associated with reduced volume in the hippocampus study.

http://www.pnas.org/content/110/20/8230.full “Neural predictors of individual differences in response to math tutoring in primary-grade school children”

Translating PTSD research findings from animals to humans

gettingwell4 0-1 star Wasted resources, Amygdala, Cortisol, Hippocampus, Limbic system, Neurochemicals, Stress

This 2014 rodent study stressed the animals, measured their stress responses, then killed them and sampled genes in their amygdala, hippocampus, and blood. The researchers found that glucocorticoid receptor signaling genes were the primary pathway associated with “exposure-related individual differences“ in stress responses for the amygdala and blood. This pathway also placed first for the hippocampus in female rats (glucocorticoid receptor was second in male rats and prostate cancer signaling was first).

I’ll quote one press article’s coverage to show where the researchers wanted to go with the study’s findings:

“We found that most of the genes and pathways that are different in PTSD [post-traumatic stress disorder]-like animals compared to resilient animals are related to the glucocorticoid receptor, which suggests we might have identified a therapeutic target for treatment of PTSD.”

How about this lead sentence:

“There may some day be a blood test to determine whether someone suffers from Post-Traumatic Stress Disorder or is at risk for the psychiatric condition.”

Here’s another article’s paraphrase of a different researcher:

“Those are genes that become activated in the presence of stress. Like a key fitting into a lock, the hormone corticosterone, produced naturally by the body, connects to the receptor and has a calming effect.

In some rodents, and apparently in some people, the pathway appears to be defective, and this puts them at higher risk for PTSD.”

Also, from the study’s abstract:

“Corticosterone treatment 1 h[our] after PSS [predator-scent-stress]-exposure prevented anxiety and hyperarousal 7 d[ays] later in both sexes, confirming the GR [glucocorticoid receptor] involvement in the PSS behavioral response.”

Like other researchers continue to do, they stopped this study short of finding causes for the effects:

  1. What were the causes for genes in the glucocorticoid receptor signaling pathway being differentially expressed? “Exposure-related individual differences” isn’t a causal finding.
  2. If this pathway is “defective,” what exactly happened to make it that way?
  3. Did dampening the effects of stress with a shot of cortisol one hour after the stress treat the cause such that the rats were cured? Since the readers of the study and associated articles were led to infer that this treatment was a cure, why destroy the treated animals afterwards before the proofs of long-term efficacy were thoroughly documented and tested?

When studies like this are carried forward with humans, researchers should try to find the causes for these effects. It isn’t sufficient to pretend that there aren’t early-life causes for these effects. Such a pretense leads to the follow-on pretense that later-life consequences are mysteries such as “exposure-related individual differences” and not effects.

Researchers should act like the subjects are feeling human beings who can participate in treatments of both the causes and effects. They should remember that humans are not lab rats who need to be fixed.

http://www.pnas.org/content/111/37/13529.full “Expression profiling associates blood and brain glucocorticoid receptor signaling with trauma-related individual differences in both sexes”

Do you know a stranger’s emotional motivations for smiling?

gettingwell4 < 0 Detracted from science, Beliefs, Cerebrum

The premise of this combination of two studies was:

“Emotional understanding is the central problem of human interaction.”

The researchers reanalyzed a 2008 study’s data, supplemented it with their own 2015 study, and found:

“Social-historical factors..explain cross-cultural variation in emotional expression and smile behavior.

We also report an original study of the underlying states that people believe [my emphasis] are signified by a smile.”

The researchers presented the subjects with a survey that asked them to rate 15 possible reasons for a person to smile at them on a seven-point scale of -3 to +3 for disagreeing/agreeing.

The research methodology didn’t take the additional necessary steps of establishing paired experiments that included presenting a similar survey to a control group of subjects to self-report their emotional motivations for smiling, and then processing the two surveys.

Did the study’s reviewer have anything to say about this lack of validation of the subjects’ beliefs to any factual measurements of a stranger’s corresponding “emotional expression and smile behavior?”

This combination of studies didn’t inform us about the “emotional understanding is the central problem of human interaction” premise. The researchers only provided evidence that the subjects’ cultures were one of many causal factors for the subjects’ beliefs about a hypothetical stranger’s smiling behavior.

The combined studies didn’t contain any emotional content to establish experimental conditions toward the goal of “emotional understanding.” No emotions were involved, for example, when a subject rated “strongly agree” to the “Wants you to like them” reason on a survey for a hypothetical stranger’s smiling behavior.

The studies didn’t show that the subjects rating their beliefs contributed to their real “emotional understanding.” Including emotional content, such as experimentally evoking an actual emotion in response to an actual stranger smiling, possibly could have contributed to real “emotional understanding.”

Research that strips out emotional content can’t factually provide evidence for real “emotional expression and smile behavior.” The degrees to which beliefs about and perceptions of a stranger’s smiling actually match their emotional reality remain to be shown.

http://www.pnas.org/content/112/19/E2429.full “Heterogeneity of long-history migration explains cultural differences in reports of emotional expressivity and the functions of smiles”