Limbic system

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”

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.

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”

Who benefits when research with no practical application becomes a politically correct meme?

gettingwell4 < 0 Detracted from science, Anterior cingulate cortex, Beliefs, Cerebrum, Limbic system, Lower brain

Do you take a risk, as this 2013 University of Texas/Yale study concluded, because you don’t foresee how you can avoid the risk?

By making this finding, the study essentially assigned the bases of a person’s risky decisions to their cerebrum.

I wasn’t persuaded. The conclusion was reached because the study’s design only engaged the subjects’ cerebrums with a video game task involving popping balloons. See Task performance and beliefs about task responses are solely cerebral exercises for a similar point.

If the researchers had instead designed a study that also engaged the subjects’ limbic system and lower brains, the findings may have been different.

Only one of the news articles covered this story with some accuracy, io9.com:

“Helfinstein (the lead researcher) doesn’t see any direct, practical applications of the research. After all, people don’t spend their lives in fMRI scanners, so it’s not as if we can tell when people are going to make a risky decision in their day-to-day activities.”

Compare that with the majority of the news coverage that hijacked the study’s findings to try to develop a politically correct meme:

“Many health-relevant risky decisions share this same structure, such as when deciding how many alcoholic beverages to drink before driving home or how much one can experiment with drugs or cigarettes before developing an addiction.”

The study found that “risk taking may be due, in part, to a failure of the control systems necessary to initiate a safe choice.” The brain areas were “primarily located in regions more active when preparing to avoid a risk than when preparing to engage in one.” These areas included the “bilateral parietal and motor regions, anterior cingulate cortex, bilateral insula, and bilateral lateral orbitofrontal cortex.”

Notice that just one of the studied brain areas (the anterior cingulate cortex) is part of the limbic system or lower brains, although the bilateral insula connects to the limbic system. Yet the limbic system and lower parts of the brain are most often the brain areas that drive real-world risky behaviors such as smoking, drug use, sexual risk taking, and unsafe driving.

A video game task of popping balloons that engaged the cerebrum was NOT informative to the cause-and-effect of the emotions and instincts and impulses from limbic system and lower brains that predominantly drive risky behavior.

Who may benefit from the misinterpretations and misdirections of the study’s findings? We can take clues from the five applicable NIH grants (UL1-DE019580, RL1MH083268, RL1MH083269, RL1DA024853, PL1MH083271) and the researchers’ statement:

“We were able to predict choice category successfully in 71.8% of cases.”

Anybody ever read Philip K. Dick?

http://www.pnas.org/content/111/7/2470.full “Predicting risky choices from brain activity patterns”

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”

Can psychologists exclude the limbic system and adequately study awareness and social cognition?

gettingwell4 < 0 Detracted from science, Amygdala, Cerebrum, Limbic system, Lower brain, Memory , , , ,

This 2014 Princeton human study was proof that cognitive researchers are stuck in the cerebrum. That and gadgets.

The researchers didn’t measure limbic system or lower brain areas, yet from their use of cartoon faces and magnetically zapping their subjects’ brains they proclaimed:

“The findings suggest a fundamental connection between private awareness and social cognition.”

For just one example of the gross omissions of the study’s design, look at the limbic system’s part in “social cognition” for The amygdala is where we integrate our perception of human facial emotion.

And it’s a very limited scope of “private awareness” that excludes conscious awareness of what’s in our own feeling, instinctual, and impulsive levels of consciousness.

http://www.pnas.org/content/111/13/5012.full “Attributing awareness to oneself and to others”

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.

Can a study exclude the limbic system and adequately find how we process value?

gettingwell4 < 0 Detracted from science, Beliefs, Cerebrum, Limbic system, Lower brain ,

This 2014 human study was notable for defining away the limbic system and lower brain from consideration in processing positive and negative stimuli for value.

However, the researchers didn’t fully reveal their biases until the last paragraph of the supplementary material, where they were obligated to comment on a previous study that included the limbic system. Good for the reviewer if that was how the researchers became obligated to deal with the previous study.

It isn’t difficult to include the limbic system in studies of value. For example, the Teenagers value rewards more and are more sensitive to punishments than are adults study found:

  • Cerebral areas increased activity when the expected value of the reward increased.
  • Limbic system areas increased activity when the expected value of the reward decreased.

http://www.pnas.org/content/111/13/5000.full “Disentangling neural representations of value and salience in the human brain”

Teenagers value rewards more and are more sensitive to punishments than are adults

gettingwell4 2-3 stars Required further work, Beliefs, Brain development, Brain hemispheres, Cerebrum, Limbic system

This 2013 human study found that adolescents placed more value on rewards than did adults. Adolescents were also more sensitive to punishments than were adults.

Cerebral areas increased activity when the expected value of the reward increased. Limbic system areas increased activity when the expected value of the reward decreased.

The left ventral striatum was the brain area that had the most increase in activity in adolescents compared with adults when the expected value of the reward increased. This brain area is usually not fully developed until people are in their mid 20s.

As the researchers noted as a limitation of the study:

“Without including preadolescents it is not possible to say with certainty whether the observed difference is a uniquely adolescent sensitivity to expected value or part of an ongoing developmental trajectory.”

Another limitation of the study was that it studied only 22 teens aged 13 to 17. Nineteen adults were studied with an average age of 28.

http://www.pnas.org/content/111/4/1646.full “Neural representation of expected value in the adolescent brain”

When do you get to live your own life?

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

This 2014 Cambridge/Stanford study asserted that for Facebook users, a computer can be a better judge of who your real self is: better than your social contacts, and in some aspects, than yourself.

There were many elements to this study. Let’s take one – impulsivity – which should be a multifaceted judgment relating to one’s own limbic system and especially lower brain, whose signature is instinctual survival reactions.

The self-assessed correlation score was .52, which was better than the computer score of .28, which was better than the .26 social contacts score.

I interpreted the impulsivity scores as people internally knowing who they really were better than what they displayed externally. A finding of the “duh” variety, although not counter to the study’s headlines.

What do you think about this study’s statement?

“Furthermore, in the future, people might abandon their own psychological judgments and rely on computers when making important life decisions, such as choosing activities, career paths, or even romantic partners. It is possible that such data-driven decisions will improve people’s lives.”

I think that’s generally possible. Whether that’s individually possible depends on who you really are.

If all your life you’ve accepted being constantly told what to do, and accepted being forced to do things “for your own good” then yes, you may accept a computer program as a substitute for your parents’ or some other external party’s authority over your life.

If this describes you, I ask: When do you get to live your own life?

http://www.pnas.org/content/112/4/1036.full “Computer-based personality judgments are more accurate than those made by humans”

Sex hormone exposure to the developing female fetus causes infertility in adulthood

gettingwell4 4-5 stars Advanced knowledge, Brain development, Epigenetics, Hypothalamus, Limbic system, Testosterone ,

This 2014 rodent study was of polycystic ovarian syndrome, which is the leading cause of human female infertility.

The researchers could reliably induce this disease in mice while they were still fetuses, but effects didn’t manifest until adulthood! The inducement method exposed the developing female fetuses to androgens such that their testosterone concentration was significantly increased.

Comparing this study with How mothers-to-be program lifelong low testosterone into their unborn male children, we can see that in early development:

  • too much testosterone for a female fetus and
  • too little testosterone for a male fetus

both have lifelong ill effects.

http://www.pnas.org/content/112/2/596.full “Enhancement of a robust arcuate GABAergic input to gonadotropin-releasing hormone neurons in a model of polycystic ovarian syndrome”

Why do researchers title their study the cortex vs. the limbic system or lower brain?

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

This 2012 review of 89 studies was ostensibly of the prefrontal cortex. The review title showed how researchers characterize their work as studying the cerebrum, even when they primarily deal with the limbic system and lower brains.

For example, the reviewer discussed rodent studies of the developing pup fetus regarding:

  • Sensory/motor – Paternal complex housing, maternal complex housing
  • Stress – Mild stress, bystander stress, moderate stress
  • Psychoactive drugs – Stimulants
  • Adult stimulants – Ethanol

The active brain areas of the rodent fetus are the brainstem and the limbic system, and those areas were primarily what was studied. The cerebrum of the developing pup is a tiny strip that has little cognitive function.

http://www.pnas.org/content/109/Supplement_2/17186.full “Experience and the developing prefrontal cortex”

The amygdala is where we integrate our perception of human facial emotion

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

We all have specialized brain circuits for recognizing faces.

Each person has their own historical judgment of the emotion in a human face, which may or may not be the emotion objectively displayed by the face.

The amygdala, not the hippocampus, was found to be where we integrate our perception of human facial emotion.

The facial information conveyed by the eyes, not the mouth, was primarily how the amygdala perceived emotion.

This 2014 study was performed on seven neurology patients who had deep-brain electrodes implanted for other purposes of diagnosis or treatment, including epilepsy and autism, and six healthy control subjects. With the electrodes, the researchers were able to measure individual neurons instead of functional MRI aggregate results.

This increased measuring capability enabled the researchers to develop other findings, such as:

“Neuronal selectivity for fear faces in the amygdala comes mainly from a suppression of activity in happy-face trials, whereas selectivity for happy faces is mainly due to an increase in activity for happy-face trials.”

Also:

“The long latency of the amygdala responses we observed already argues for considerable synthesis, consistent with the integration of face input from temporal cortex with signals from other brain regions, as well as substantial processing internal to the amygdala.”

http://www.pnas.org/content/111/30/E3110.full “Neurons in the human amygdala selective for perceived emotion”

Both sexes can be skilled child caregivers when we put time and effort into it

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

My POV of this 2014 Israeli study’s findings, at the risk of being dragged into the politically-correct quagmire:

  • Mothers (heterosexual primary-caregiving) mainly used areas of their limbic systems to care for children;
  • Fathers (heterosexual secondary-caregiving) mainly used areas of their cerebrums to care for children;
  • Fathers (homosexual primary-caregiving) mainly used both their limbic systems and cerebrums to care for children.

Findings of the “duh” variety:

  • Women have a built-in capacity to care for children before they have children;
  • Men can learn to care for children;
  • Both sexes can be skilled child caregivers when we put time and effort into it.

“Although only mothers experience pregnancy, birth, and lactation, and these provide powerful primers for the expression of maternal care via amygdala sensitization, evolution created other pathways for adaptation to the parental role in human fathers, and these alternative pathways come with practice, attunement, and day-by-day caregiving.”

http://www.pnas.org/content/111/27/9792.full “Father’s brain is sensitive to childcare experiences”