Corpus callosum

The effects of imposing helplessness

gettingwell4 2-3 stars Required further work, Amygdala, Brainstem, Cerebrum, Epigenetics, Hippocampus, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Stress , , , , , , ,

This 2016 New York rodent study found:

“By using unbiased and whole-brain imaging techniques, we uncover a number of cortical and subcortical brain structures that have lower activity in the animals showing helplessness than in those showing resilience following the LH [learned helplessness] procedure. We also identified the LC [locus coeruleus] as the sole subcortical area that had enhanced activity in helpless animals compared with resilient ones.

Some of the brain areas identified in this study – such as areas in the mPFC [medial prefrontal cortex], hippocampus, and amygdala – have been previously implicated in clinical depression or depression-like behavior in animal models. We also identified novel brain regions previously not associated with helplessness. For example, the OT [olfactory tubercle], an area involved in odor processing as well as high cognitive functions including reward processing, and the Edinger–Westphal nucleus containing centrally projecting neurons implicated in stress adaptation.

The brains of helpless animals are locked in a highly stereotypic pathological state.”

Concerning the study’s young adult male subjects:

“To achieve a subsequent detection of neuronal activity related to distinct behavioral responses, we used the c-fosGFP transgenic mice expressing c-FosGFP under the control of a c-fos promoter. The expression of the c-fosGFP transgene has been previously validated to faithfully represent endogenous c-fos expression.

Similar to wild-type mice, approximately 22% (32 of 144) of the c-fosGFP mice showed helplessness.”

The final sentence of the Introduction section:

“Our study..supports the view that defining neuronal circuits underlying stress-induced depression-like behavior in animal models can help identify new targets for the treatment of depression.”

Helplessness is both a learned behavior and a cumulative set of experiences during every human’s early life. Therapeutic approaches to detrimental effects of helplessness can be different with humans than with rodents in that we can address causes.

The researchers categorized activity in brain circuits as causal in the Discussion section:

“Future studies aimed at manipulating these identified neural changes are required for determining whether they are causally related to the expression of helplessness or resilience.”

Studying whether or not activity in brain circuits induces helplessness in rodents may not inform us about causes of helplessness in humans. Our experiences are often the ultimate causes of helplessness effects. Many of our experiential “neural changes” are only effects, as demonstrated by this and other studies’ induced phenotypes such as “Learned Helplessness” and “Prenatally Restraint Stressed.”

Weren’t the researchers satisfied that the study confirmed what was known and made new findings? Why attempt to extend animal models that only treat effects to humans, as implied in the Introduction above and in the final sentence of the Discussion section:

“Future studies aimed at elucidating the specific roles of these regions in the pathophysiology of depression as well as serve as neural circuit-based targets for the development of novel therapeutics.”

http://journal.frontiersin.org/article/10.3389/fncir.2016.00003/full “Whole-Brain Mapping of Neuronal Activity in the Learned Helplessness Model of Depression” (Thanks to A Paper a Day Keeps the Scientist Okay)

Where do our beliefs about our children come from? An autism example

gettingwell4 < 0 Detracted from science, Beliefs, Brain development, Cerebrum, Epigenetics, Glutamate, Limbic system, Neurochemicals, Primal Therapy , , , ,

A 2015 case study by Ohio physicians highlighted:

“Although only a small minority of patients with autism have a mitochondrial disease, many patients with mitochondrial myopathies have autism spectrum disorder symptoms.

These symptoms may be the presenting symptoms, which presents a diagnostic challenge for clinicians.

The case of a 15-year-old boy with a history of autism spectrum disorder and neurocardiogenic syncope, admitted to the inpatient unit for self-injury, whose young mother, age 35, was discovered to suffer from mitochondrial myopathy, dysautonomia, neurocardiogenic syncope, Ehler-Danlos syndrome, and other uncommon multisystem pathologies likely related to mitochondrial dysfunction.”

I was somewhat taken aback by the Abstract and Introduction statements:

“All autism spectrum disorders are known to be heritable, via genetic and/or epigenetic mechanisms, but specific modes of inheritance are not well characterized.

This form of ASD is known to be heritable, as are all forms of ASD, despite the previous belief to the contrary, though the mechanisms of inheritance, both genetic and epigenetic, are not well characterized.”

The definition of heritable as used was “able to be passed from parent to child before birth.” The reference provided was a 2014 French review Gene × Environment Interactions in Autism Spectrum Disorders: Role of Epigenetic Mechanisms.

I didn’t see the “known to be heritable” phrase mentioned in the referenced review. However, I also didn’t see anything stated in the review or cited from its 217 references that disproved this phrase.

I shouldn’t have been surprised by “despite the previous belief to the contrary” in the above quotation. I’d guess that the physicians frequently encountered parents who needed such beliefs when faced with their child’s condition.

A relevant hypothesis of Dr. Arthur Janov’s Primal Therapy is: a major function that our cerebrums have evolutionarily adapted is to use ideas and beliefs to repress pain and make us more comfortable.

I value this inference as an empathetic method of interpreting people’s behaviors and expressions of thoughts and feelings.

When a “known to be heritable” phrase can unleash pain, it likely won’t be understood in its appropriate context. Among the physicians’ challenges was a barrier that kept the parent’s pain from being felt – the belief.

http://innovationscns.com/autism-in-the-son-of-a-woman-with-mitochondrial-myopathy-and-dysautonomia-a-case-report/ “Autism in the Son of a Woman with Mitochondrial Myopathy and Dysautonomia: A Case Report”

2023 update – After all the medical gaslighting on display this decade, I don’t what it would take for me to trust a medical professional anymore. These doctors ‘knew’ somehow that autism was heritable, yet couldn’t describe mechanisms of inheritance? Please. Why were medical professionals trusted in the first place?

Do strong emotions cause our brain hemispheres to interact more closely?

gettingwell4 2-3 stars Required further work, Brain hemispheres, Cerebrum, Limbic system, Memory, Primal Therapy , ,

This 2015 human/macaque study found:

“The functional coordination between the two hemispheres of the brain is maintained by strong and stable interactions.

These findings suggest a notable role for the corpus callosum in maintaining stable functional communication between hemispheres.”

The human subjects were asked to:

“Generate four negative autobiographical memories and create word cues that reminded them of each event. Participants then underwent a 6-min IR fMRI scan during which they were cued with the words they had created to recall the two most negative autobiographic memories generated outside the scanner.”

However, the study’s supplementary material didn’t address why the researchers used this particular technique.

Does recalling strong emotional memories that engage our limbic systems cause our brain hemispheres to interact more closely than do cerebral exercises?

This study demonstrated that including emotional content in brain studies was essential. It may have provided additional information had the researchers also used the two least-negative emotional memories.

As noted in Agenda-driven research on emotional memories, one hypothesis of Dr. Arthur Janov’s Primal Therapy is that recalling an emotional memory engages one’s brain differently than does re-experiencing an emotional memory. Asking the subjects to attempt to re-experience the two least-negative emotional memories may have provided data relevant to the study.

I didn’t understand why macaques were used as subjects. The researchers didn’t provide any tasks for the monkeys during the scans. The information this study gained only duplicated other studies.

Also, the monkeys were anesthetized throughout the experiments. An assumption that wasn’t addressed: fMRI scan data on anesthetized macaques provided comparable evidence to fMRI scan data on normal non-anesthetized humans who were recalling emotional memories?

Did the researchers use macaques simply because they were available?

http://www.pnas.org/content/112/20/6473.full “Stable long-range interhemispheric coordination is supported by direct anatomical projections”

What causes disconnection between the limbic system and the cerebrum?

gettingwell4 0-1 star Wasted resources, Cerebrum, Dopamine, Glutamate, Hippocampus, Limbic system, Memory, Neurochemicals

This 2014 Swedish human study with 339 subjects aged 25-80 years old found that as the subjects’ age increased, their hippocampus became less connected to their cerebrums:

“Age-related cortico–hippocampal functional connectivity disruption leads to a more functionally isolated hippocampus at rest, which translates into aberrant hippocampal decoupling and deficits in active mnemonic processing.”

The lead researcher said:

“What we can now show is that memory problems that come with increased age are most likely due to a process where the interaction among different regions of the hippocampus increases in response to less inhibitory cortical input. This in turn means that the hippocampus risks being more isolated from other important networks in the brain which impacts our ability to actively engage the hippocampus, for example to remember different events.”

Like other researchers commonly do, they excluded emotional content from the study. See another Swedish study Emotional memories and out-of-body–induced hippocampal amnesia as an example of why emotional memories are necessary in order to properly study the hippocampus.

1) As a result of excluding emotional content and other aspects of the study’ design such as using 25 as the beginning age of the subjects, all the researchers could muster as a explanatory factor was age. However, they had to couch their findings as “age-related” because age in and of itself wasn’t a causal explanation for the observed effects.

2) The findings weren’t even truly “age-related”  because, for example, the study didn’t necessarily apply to people below the age of 25. Had the study included 10-18 year old subjects, the researchers may have found that “less inhibitory cortical input” may also be present before puberty, as The prefrontal cortex develops more repressive function at puberty study indicated.

3) Had the study design included neurochemicals, the researchers may have found that “cortico–hippocampal functional connectivity disruption” was due to factors that influenced dopamine and glutamate levels, as A mechanistic study of neurotransmitters in the hippocampus indicated.

4) A finding that “cortico–hippocampal functional connectivity disruption” was influenced by other factors may also have been made had the study design included the subjects’ histories. Per my Welcome page, the findings of much of the recent research I’ve curated on this blog, and the references in those studies show that when basic needs aren’t met, especially early in people’s lives, and the painful conditions persist, enduring physiological changes may occur.

5) What the researchers noted in the study’s limitation paragraph were references to fMRI scans rather than limitations such as those mentioned above regarding the study design. The study provided unconvincing evidence for causes of “cortico–hippocampal functional connectivity disruption” and it wasn’t because of fMRI limitations.

http://www.pnas.org/content/111/49/17654.full “Elevated hippocampal resting-state connectivity underlies deficient neurocognitive function in aging”

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.

Neural plasticity trumps genetics in the hippocampus part of the limbic system

gettingwell4 2-3 stars Required further work, Brain development, Epigenetics, Hippocampus, Limbic system, Memory , ,

This 2015 rodent study used a genetic strain of mice that was bred to not express a gene that enabled long-term memory in the hippocampus. The mice were not memory-impaired, however, due to their brains’ neural plasticity.

The researchers found:

“Deletion of genes in organisms does not always give rise to phenotypes because of the existence of compensation.

The current work provides an example of how a complex brain system may adjust to the effects of gene deletion to recover function.”

The Early human brain development can be greatly modified by environmental factors study showed even greater plasticity in another part of the human brain where the people faced much larger obstacles than gene deletion.

I view this finding as a cautionary tale to reference any time a study comes out stating that A and B genes are found to cause X and Y symptoms or behavior. Researchers don’t have enough evidence in 2015 to unequivocally describe what rodent brains are capable of, much less human brains.

The researchers implied how they kept faith in their work with the phrase:

“The compensatory mechanism is imperfect and does not fully restore cGKII-dependent function.”

Is perfection the standard to which their research is also held?

http://www.pnas.org/content/112/10/3122.full “Network compensation of cyclic GMP-dependent protein kinase II knockout in the hippocampus by Ca2+-permeable AMPA receptors”

Early human brain development can be greatly modified by environmental factors

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

This 2014 Brazilian human study found that the brains of people born without the corpus callosum, the major connection between brain hemispheres, adapted to this loss:

“The authors believe that the development of alternative pathways results from the brain’s ability for long-distance plasticity and occurs in the utero during embryo development, which indicates that connections formed in the human brain early in development can be greatly modified, and most likely by environmental or genetic factors.”

BRAVO! MORE STUDIES LIKE THIS ONE!

People have limited capability to adapt later in life to corpus callosum injuries or to brain hemisphere disconnection.

http://www.pnas.org/content/111/21/7843.full “Structural and functional brain rewiring clarifies preserved interhemispheric transfer in humans born without the corpus callosum”