This 2014 human study showed that the way our cerebrums visually processed objects depended on what use we think we would make of the objects.
http://www.pnas.org/content/111/10/E962.full “Task context impacts visual object processing differentially across the cortex”
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”
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”
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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:
http://www.pnas.org/content/111/13/5000.full “Disentangling neural representations of value and salience in the human brain”
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”
This 2013 human study added to the existing understanding of how our brain hemispheres work.
“The main contribution of our study is to demonstrate, at a whole-brain scope, the qualitative differences between the hemispheres in their within- and between-hemisphere interactions. The correlations with behavioral ability really hammer this distinction home, since one needed to use the appropriate metric – that is, segregation versus integration – to see these correlations.
..the left hemisphere showing a preference to interact more exclusively with itself, particularly for cortical regions involved in language and fine motor coordination. In contrast, right-hemisphere cortical regions involved in visuospatial and attentional processing interact in a more integrative fashion with both hemispheres.
The degree of lateralization present in these distinct systems selectively predicted behavioral measures of verbal and visuospatial ability, providing direct evidence that lateralization is associated with enhanced cognitive ability.”
A paraphrase of this last sentence may be that our overall cognitive ability is enhanced when we develop the functional specializations of both brain hemispheres.
http://www.pnas.org/content/110/36/E3435.full “Two distinct forms of functional lateralization in the human 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”
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:
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”
This 2014 ivy league human study found that what appeared to be genetic links may have been epigenetic responses to our environment.
Curiously, none of the news articles covering this study highlighted the lack of the most influential environments on epigenetic DNA changes:
This omission may have been because the study intentionally didn’t support such an interpretation. Here’s a partial explanation from the study’s supplementary material of the “family fixed-effects model” the researchers developed:
“The family fixed-effects model blocks both genetic factors and parental characteristics/behaviors that are common to family members (e.g., siblings), including unmeasured factors; therefore, from the perspective of confounding, the fixed-effect specification is preferred.”
When the preferred model blocked the most important environments in which epigenetic DNA changes occur, what environments remained?
“These results suggest genetic influences on complex traits like obesity can vary over time, presumably because of global environmental changes that modify allelic penetrance.”
Although a finding attributing “global environmental changes” made more funding available to the researchers, it was rightly an outlier from the majority of epigenetic studies.
This finding made me start a negative rating for studies that DETRACT from science!
Why was the reviewer okay with the study’s model omitting the most important factors in human development? The study’s model defined away both the:
in order to manufacture a politically-correct epigenetics meme!
How else to interpret this statement, if not intended to generate a meme?
“Our results underscore the importance of interpreting any genetic studies with a grain of salt and leave open the possibility that new genetic risk factors may be seen in the future due to different genetically driven responses to our ever-changing environment.”
http://www.pnas.org/content/112/2/354.full “Cohort of birth modifies the association between FTO genotype and BMI”
This 2014 study found that unconventional and groundbreaking research was routinely rejected by medical journals:
“Our research suggests that evaluative strategies that increase the mean quality of published science may also increase the risk of rejecting unconventional or outstanding work.”
The study was also a collateral indication of the degree to which peer reviewers didn’t try to advance science.
http://www.pnas.org/content/112/2/360.full “Measuring the effectiveness of scientific gatekeeping”
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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:
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”
This 2012 human study found that infant language development accelerated when the depressed mother-to-be took antidepressants:
“Language acquisition reflects a complex interplay between biology and early experience.
Psychotropic medication exposure has been shown to alter neural plasticity and shift sensitive periods in perceptual development.”
Infant language development was delayed when the depressed mother-to-be didn’t take serotonin reuptake inhibitor medication:
“Prenatal depressed maternal mood and (S)SRI exposure were found to shift developmental milestones bidirectionally on infant speech perception tasks.”
Contrast this study with Problematic research with telomere length, which pretended that maternal depression had negligible epigenetic effects on the developing fetus, infant, and child.
http://www.pnas.org/content/109/Supplement_2/17221.full “Prenatal exposure to antidepressants and depressed maternal mood alter trajectory of infant speech perception”
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”
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”
This 2014 primate study provided additional details on the specialized brain circuits for recognizing faces:
“The current finding that neurons commonly give similar responses upon seeing the same faces months apart raises the possibility that some neurons might respond the same way to the same individual faces over most of the animal’s lifespan.”
But the finding could also have been:
“Another example of a biological system maintaining its complex organization as the constituent components are exchanged.”
http://www.pnas.org/content/111/22/8251.full “Face-selective neurons maintain consistent visual responses across months”
Surface Your Real Self 