Limbic system

More from the researchers that found people had the same personalities at age 26 that they had at age 3

gettingwell4 2-3 stars Required further work, Brain development, Cerebrum, Limbic system, Lower brain ,

This 2014 research came from the Dunedin Study in New Zealand that has studied a group of over 1,000 people for 40+ years now. They first came to worldwide fame by finding that the study’s participants at age 26 largely had the same personality that each did at age 3.

The current study linked the participants’ childhood cognitive abilities and self-control to their current cardiac age.

Would a US doctor have the knowledge and foresight to understand that significant factors in a middle-aged patient’s cardiac health came from their early childhood, infancy, or womb life experiences?

http://www.pnas.org/content/111/48/17087.full “Credit scores, cardiovascular disease risk, and human capital”

An example of how we are unaware of some of the unconscious bases of our decisions

gettingwell4 0-1 star Wasted resources, Beliefs, Cerebrum, Limbic system, Lower brain , ,

This 2014 human study provided details of how we are unaware of some of the unconscious bases of our decisions:

“We show that unconscious information can be accumulated over time and integrated with conscious elements presented either before or after to boost or diminish decision accuracy.

The unconscious information could only be used when some conscious decision-relevant information was also present.

Surprisingly, the unconscious boost in accuracy was not accompanied by corresponding increases in confidence, suggesting that we have poor metacognition for unconscious decisional evidence.”

I wouldn’t agree that these findings apply as broadly as the researchers said they did during interviews.

The first reason is that the researchers restricted the study to the subjects’ cerebrums’ visual processing. In everyday life, though, our limbic systems and lower brains are also very much involved with visual processing.

As an example, have you ever taken a nature walk where you instinctually jumped back from a vague initial impression only to find that the object was a stick? I’ve done that many times, and our shared human instincts operating with the limbic system and lower brain saved me once in childhood from stepping on a copperhead snake.

Secondly, the researchers limited the term “unconscious” to mean below visual perception of the subjects’ cerebrums.

What if, for example, the study’s visual cues included emotional content that involved the subjects’ limbic systems? The researchers may have able to develop a basis for findings that applied to common operations such as making decisions that are influenced by unconscious emotional content.

The third reason to not apply the findings as broadly as the researchers may have desired is that the researchers limited the term “metacognition” to operations of the the subjects’ cerebrums. We know that Task performance and beliefs about task responses are solely cerebral exercises, which accurately describes the metacognition experiment.

As an example of how people’s metacognitions are much broader than just their cerebrums, I take a crowded train to and from work everyday. It’s fairly straightforward to understand people’s actions, body postures, and facial expressions in terms of the combined metacognition operations of their entire brains.

Also, the metacognition finding sample size may have been too small by involving only five subjects.

http://www.pnas.org/content/111/45/16214.full “Unconscious information changes decision accuracy but not confidence”

Are you feeling kinda blue? Think your brain cells are too few? Get your fat cells on that bike and ride!

gettingwell4 2-3 stars Required further work, Hippocampus, Limbic system

This 2014 rodent study found that fat cells released a certain hormone during exercise that produced two beneficial effects:

  • the hormone increased hippocampal neurogenesis;
  • it also reduced depression-like behaviors.

So if you’re feeling kinda blue,

Think your brain cells are too few?

Get your fat cells on that bike and ride!

http://www.pnas.org/content/111/44/15810.full “Physical exercise-induced hippocampal neurogenesis and antidepressant effects are mediated by the adipocyte hormone adiponectin”

Fear extinction is the learned inhibition of retrieval of previously acquired responses

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Cerebrum, Epigenetics, Hippocampus, Limbic system, Memory

This 2014 rodent study showed that fear extinction doesn’t depend on memory retrieval:

“These results show that extinction and retrieval are separate processes and strongly suggest that extinction is triggered or gated by the conditioned stimulus even in the absence of retrieval.”

Key to my understanding this finding came from a definition in another summary study by the authors, The learning of fear extinction, where they stated:

“Extinction is the learned inhibition of retrieval of previously acquired responses.”

These two studies and Hippocampal mechanisms involved in the enhancement of fear extinction caused by exposure to novelty should inform researchers of studies such as If rodent training has beneficial epigenetic effects, how can the next step be human gene therapy? of desirable alternative treatments, rather than proceeding from rodent training directly to human gene therapy.

http://www.pnas.org/content/112/2/E230.full “Extinction learning, which consists of the inhibition of retrieval, can be learned without retrieval”

What is the purpose of music? A review of evolutionary and pleasurable research findings

gettingwell4 2-3 stars Required further work, Amygdala, Anterior cingulate cortex, Cerebrum, Dopamine, Hippocampus, Hypothalamus, Limbic system, Lower brain, Neurochemicals

Ever wonder what happens in your brain and body when you get chills from a musical performance?

This 2013 summary review of 126 studies provided details of brain areas that contribute to our enjoyment of music.

Much of the review addressed Darwin’s observation that music had no readily apparent functional consequence and no clear-cut adaptive function. The researchers noted that:

“There is scant evidence that other species possess the mental machinery to decode music in the way humans do, or to derive enjoyment from it.”

The reasons why different types of music affect us differently are similar to the findings of the Reciprocity behaviors differ as to whether we seek cerebral vs. limbic system rewards study.

Here are the “We seek limbic system rewards” similarities:

“The nucleus accumbens played an important role with both familiar and novel music. In the case of familiar music, hemodynamic activity in the nucleus accumbens was associated with increasing pleasure, and maximally expressed during the experience of chills, which represent the peak emotional response; these were the same regions that showed dopamine release. The nucleus accumbens is tightly connected with subcortical limbic areas of the brain, implicated in processing, detecting, and expressing emotions, including the amygdala and hippocampus. It is also connected to the hypothalamus, insula, and anterior cingulate cortex, all of which are implicated in controlling the autonomic nervous system, and may be responsible for the psychophysiological phenomena associated with listening to music and emotional arousal.”

Here is the “We seek cerebral rewards” part.

“Finally, the nucleus accumbens is tightly integrated with cortical areas implicated in “high-level” processing of emotions that integrate information from various sources, including the orbital and ventromedial frontal lobe. These areas are largely implicated in assigning and maintaining reward value to stimuli and may be critical in evaluating the significance of abstract stimuli that we consider pleasurable.”

http://www.pnas.org/content/110/Supplement_2/10430.full “From perception to pleasure: Music and its neural substrates”

Using expectations of oxytocin to induce positive placebo effects of touching

gettingwell4 2-3 stars Required further work, Amygdala, Beliefs, Brain hemispheres, Limbic system, Neurochemicals, Oxytocin, Thalamus

This 2013 Scandinavian study detailed which brain structures were involved when fooling oneself about actual sensations in favor of expected sensations.

It was hilarious how the researchers used studies of oxytocin to create expectations in the subjects:

“To induce expectation of intranasal oxytocin’s beneficial effects on painful and pleasant touch experience, participants viewed a 6-min locally developed video documentary about oxytocin’s putative prosocial effects such as involvement in bonding, love, grooming, affective touch, and healing. As all of the material was based on published research, there was no deception. The video concluded that a nasal spray of oxytocin might enhance the pleasantness of:

  • (i) stroking and
  • (ii) warm touch, and
  • (iii) reduce the unpleasantness of pain.”

Other items:

  • Only the placebo effects for the warm and pain-reducing touches were statistically significant, not the stroking touch;
  • The a priori brain areas monitored in the “sensory circuitry” included the thalamus and were all in the right brain hemisphere;
  • The a priori brain areas monitored in the “emotional appraisal circuitry” included the amygdala.

One way the researchers summarized the study was:

“Pain reduction dampened sensory processing in the brain, whereas increased touch pleasantness increased sensory processing.”

This finding demonstrated how the thalamus part of the limbic system actively controls and gates information to and from the cerebrum, similar to the Thalamus gating and control of the limbic system and cerebrum is a form of memory study.

There was a terminology problem in the study, evidenced by statements such as:

“We induced placebo improvement of both negative and positive feelings (painful and pleasant touch).”

Touch is a sensation, not a feeling or emotion. This placebo study created expectations of sensations in the subjects’ cerebrums, not expectations of emotions.

Also, including parts of the limbic system such as the amygdala in the “emotional appraisal circuitry” didn’t mean that the researchers studied feelings or emotions. We know from research summarized in the Conscious mental states should not be the first-choice explanation of behavior study that:

“Neither amygdala activity nor amygdala-controlled responses are telltale signatures of fearful feelings.“

The current study cast additional light on the dubious Problematic research on human happiness study. Those researchers were fooled by a positive placebo effect!

http://www.pnas.org/content/110/44/17993.full “Placebo improves pleasure and pain through opposite modulation of sensory processing”

What happens next after a detox program predictably fails?

gettingwell4 0-1 star Wasted resources, Beliefs, Limbic system, Lower brain, Memory, Primal Therapy , ,

This 2014 study was a misguided example of looking solely at the presenting parts of a person’s condition rather than the whole historical person.

What did this study’s researchers decide after finding:

“Alcohol-dependent subjects..remained with high scores of depression, anxiety, and alcohol craving after a short-term detoxification program.”

Was it that the detox program didn’t work because it dealt with suppressing symptoms rather than addressing causes?

NO!

The researchers decided:

“Gut microbiota seems to be a previously unidentified target in the management of alcohol dependence.”

The researchers proceeded on some trendy, in-vogue aspect of their patients with which to tinker.

The researchers ignored that the correlation of the new treatment course didn’t show causation. They also ignored underlying causes for the ineffectiveness of the preceding treatments of symptoms.

Hard to see how the reviewer believed that this study would advance science.

Meanwhile, the researchers continued to ignore the elephants in the room: the relationships of the patients’ histories and their pain.

http://www.pnas.org/content/111/42/E4485.full “Intestinal permeability, gut-bacterial dysbiosis, and behavioral markers of alcohol-dependence severity”

If research provides evidence for the causes of stress-related disorders, why only focus on treating the symptoms?

gettingwell4 0-1 star Wasted resources, Brainstem, Cortisol, Hippocampus, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Stress , , ,

This 2014 rodent research reliably induced many disorders common to humans. Here are some post-birth problems the researchers caused, primarily by applying different types of stress, as detailed in the study’s supplementary material:

Yet the researchers’ goal was to identify a brain receptor for:

“Novel therapeutic targets for stress-related disorders.”

In other words, develop new drugs to treat the symptoms.

Where are the studies that have goals to prevent these common problems being caused in humans by humans?

Where is the research on treatments to reverse the enduring physiological impacts to stress by treating the causes?

What do you think of this excerpt?

“Accumulating evidence suggests that traumatic events particularly during early life (e.g., parental loss or neglect) coupled with genetic factors are important risk factors for the development of depression and anxiety disorders.

Moreover, the brain is particularly vulnerable to the effects of stress during this period.

Maternal separation in rodents is a useful model of early-life stress that results in enduring physiological and behavioral changes that persist into adulthood, including increased hypothalamic–pituitary–adrenal (HPA)–axis sensitivity, increased anxiety, and visceral hypersensitivity.”

http://www.pnas.org/content/111/42/15232.full “GABAB(1) receptor subunit isoforms differentially regulate stress resilience”

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”

Hypothalamic oxytocin and vasopressin have sex-specific effects on pair bonding, gregariousness, and aggression

gettingwell4 4-5 stars Advanced knowledge, Hypothalamus, Limbic system, Neurochemicals, Oxytocin, Stress, Vasopressin

This 2014 bird study showed the complementary effects of neurochemicals vasopressin and oxytocin in the hypothalamus.

Oxytocin neurons in the hypothalamus promote pair bonding and gregariousness in females.

Vasopressin neurons in the hypothalamus promote maternal care, social recognition, and gregariousness in both males and females, and aggression in males toward females.

Vasopressin and oxytocin released generally and in other parts of the brain have different effects. For example:

“Central administration of oxytocin also attenuates stress-induced effects on the brain and reverses stress-induced social avoidance.”

http://www.pnas.org/content/111/16/6069.full “Hypothalamic oxytocin and vasopressin neurons exert sex-specific effects on pair bonding, gregariousness, and aggression in finches”

Flooding the hypothalamus with neurochemicals affects reward-seeking, motivated, and depressive behavior

gettingwell4 4-5 stars Advanced knowledge, Hypothalamus, Limbic system, Lower brain, Neurochemicals

This 2014 rodent study showed the opposing effects of neurochemicals orexin (excitator) and dynorphin (inhibitor) in the hypothalamus.

The hypothalamus plays a role in behaviors such as addiction and impulsiveness. Food and cocaine self-administration were the main techniques used.

Flooding the hypothalamus with orexin produced reward-seeking and motivated behavior. That was greatly reduced when dynorphin levels were increased, and depressive behavior set in.

http://www.pnas.org/content/111/16/E1648.full “Hypocretin (orexin) facilitates reward by attenuating the antireward effects of its cotransmitter dynorphin in ventral tegmental area”

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”

Problematic research on oxytocin: If the study design excludes women, its findings cannot include women

gettingwell4 < 0 Detracted from science, Cerebrum, Limbic system, Neurochemicals, Oxytocin , ,

This 2014 study’s findings that “the hormone oxytocin promotes group-serving dishonesty” can’t apply generally to humans because its subjects were ALL men.

Regarding oxytocin, the researchers certainly knew or should have known previous studies’ findings about sex differences, as did Is oxytocin why more women than men like horror movies? which cited:

“Oxytocin modulates brain activity differently in male and female subjects.”

Regarding differing reciprocal behaviors, the researchers also knew or should have been better informed about associated brain areas through studies such as Reciprocity behaviors differ as to whether we seek cerebral vs. limbic system rewards and its references.

And how could the study produce reliable, replicable evidence of:

“Dishonesty to be plastic and rooted in evolved neurobiological circuitries”

when the researchers performed NO measurements of “neurobiological circuitries” that supported that finding?

What was the agenda in play here? What did the female Princeton reviewer see in this study that advanced science?

http://www.pnas.org/content/111/15/5503.full “Oxytocin promotes group-serving dishonesty”

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Is oxytocin why more women than men like horror movies?

gettingwell4 2-3 stars Required further work, Amygdala, Brain hemispheres, Limbic system, Neurochemicals, Oxytocin, Serotonin

This 2014 human study showed how oxytocin regulates serotonin with the involvement of the right part of the amygdala.

The following passage caught my eye as a possible explanation of why more women than men prefer horror movies: oxytocin?

“We have chosen to enroll male subjects only to avoid the confounding effects linked to sex and a possible interaction with gonadal steroids. Indeed, as shown by previous studies, oxytocin modulates brain activity differently in male and female subjects.

For instance, oxytocin suppresses amygdala response to emotionally threatening stimuli in males but enhances the same response in females.“

http://www.pnas.org/content/111/23/8637.full “Switching brain serotonin with oxytocin”