Advanced knowledge
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 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 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 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 Japanese human study showed which brain areas were involved in indirect reciprocity. It was mainly cerebral areas that were active in:
“Reputation-based reciprocity, in which they help others with good reputations to gain good reputations themselves.”
Previous studies found much the same with direct reciprocity, where an individual was reimbursed by someone who directly owed them a debt of cooperation.
It was mainly limbic system areas that were active in:
“Pay-it-forward reciprocity, in which, independently of reputations, they help others after being helped by someone else.”
The researchers compared and contrasted self-interested behaviors of:
both of which sought rewards in the cerebrum, with empathetic behaviors of:
where the subjects sought emotional rewards in the limbic system.
http://www.pnas.org/content/111/11/3990.full “Two distinct neural mechanisms underlying indirect reciprocity”
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.
This 2014 Yale study found that providing scientific explanations of patients’ conditions actually REDUCED an important part of what patients may need from therapists – empathy.
That finding summed up the malaise throughout the current dog-and-pony-show approaches in psychotherapy, where:
http://www.pnas.org/content/111/50/17786.full “Effects of biological explanations for mental disorders on clinicians’ empathy”
This 2014 Montreal study provided more evidence of critical periods during human development:
“Clearly illustrates that early acquired information is maintained in the brain and that early experiences unconsciously influence neural processing for years, if not indefinitely.
We show that internationally adopted children (aged 9–17 years) from China, exposed exclusively to French since adoption (mean age of adoption, 12.8 mo), maintained neural representations of their birth language despite functionally losing that language and having no conscious recollection of it.
We show that neural representations are not overwritten and suggest a special status for language input obtained during the first year of development.”
YES! GIVE US MORE STUDIES LIKE THIS ONE!
http://www.pnas.org/content/111/48/17314.full “Mapping the unconscious maintenance of a lost first language”
This 2014 rodent study gave further details that:
“Chronic stress, which can precipitate depression, induces changes in the architecture and plasticity of apical dendrites that are particularly evident in the CA3 region of the hippocampus.”
Other studies on the hippocampus CA3 region include:
http://www.pnas.org/content/111/45/16130.full “Role for NUP62 depletion and PYK2 redistribution in dendritic retraction resulting from chronic stress”
This 2014 human study found:
“..(brain) areas that respond reliably during spontaneous and rehearsed speech production of the same real-world story are the same.”
This finding highlighted the difficulty a therapist or researcher may encounter in objectively determining another person’s reality.
If the listener relied solely on words and speech, they may not be able to tell whether what’s heard was a planned narrative or if the speech had some other origin. That’s why in Dr. Arthur Janov’s Primal Therapy, for example, the therapist is trained to look beyond the patient’s words to ascertain the feeling being expressed.
Also:
“Production of a real-life narrative is not localized to the left hemisphere but recruits an extensive bilateral network.”
http://www.pnas.org/content/111/43/E4687.full “Coupled neural systems underlie the production and comprehension of naturalistic narrative speech”
This 2013 Quebec human epigenetic study found that DNA methylation – chemical modification that causes genes to express differently – as durably detectable between siblings born before and after their mother’s gastric bypass surgery.
The younger, post-maternal-surgery siblings were found to have DNA indicating reduced risks of developing diabetes and heart disease when compared with the DNA of their older, pre-maternal-surgery siblings. The mothers’ average weight loss was 103 lbs.
It was notable to see this famous research reference cited:
“Prenatal exposure to famine during the Dutch hunger winter of 1944 is associated with obesity with less DNA methylation (“undermethylation”) of the imprinted insulin-like growth factor 2 (IGF2) gene in exposed offspring relative to their unexposed siblings.”
It was also notable to see the reactions to this non-politically-correct finding. For one example, this news article was in full-fledged denial, stating:
“Nor do investigators know whether a father’s weight loss might have a similar impact. It’s also possible that epigenetic inheritance wasn’t at play.”
Other news coverage expressed the memes that:
http://www.pnas.org/content/110/28/11439.full “Differential methylation in glucoregulatory genes of offspring born before vs. after maternal gastrointestinal bypass surgery”
This 2014 La Jolla rodent study showed that treating the symptoms of an inherited disease can, through epigenetic DNA methylation, positively treat the symptoms in the subjects’ offspring.
The disease studied was Huntington’s, which is the most common inherited neurodegenerative disease:
Per the definitions in A review of epigenetic transgenerational inheritance of reproductive disease and Transgenerational effects of early environmental insults on aging and disease, for the term in the study’s title “transgenerational effects” to apply, the researchers needed to provide evidence in at least the next 2 male and/or 3 female generations of:
“Altered epigenetic information between generations in the absence of continued environmental exposure.”
The study instead provided evidence for intergenerational effects.
http://www.pnas.org/content/112/1/E56.full “HDAC inhibition imparts beneficial transgenerational effects in Huntington’s disease mice via altered DNA and histone methylation”
This 2014 MIT/Harvard rodent study provided evidence that specific brainstem neurons (cholinergic, or containing acetylcholine) regulated dream sleep.
The researchers used a more exact technique that selectively activated just one neuron. They made the neurons in this study sensitive to light using an algae protein that responded to a specific light frequency. Once expressed in the neuron, the protein activated the neuron when that specific frequency of light was shown onto it.
“Interestingly, both manipulations resulted in a change in the number of REM [rapid eye movement] sleep episodes and did not change REM sleep episode duration, suggesting that the PPT [pedunculopontine tegmentumis part of the brainstem] involved in REM sleep initiation but not REM sleep maintenance.”
http://www.pnas.org/content/112/2/584.full “Optogenetic activation of cholinergic neurons in the PPT or LDT induces REM sleep”
This 2014 rodent study provided further information on the locus coeruleus segment of the brainstem:
“The brainstem nucleus locus coeruleus is the primary source of norepinephrine to the mammalian neocortex.
Neurons in the locus coeruleus maintain segregated connections to brain regions with distinctly different functions. Specifically, cells that communicate with the prefrontal cortex, a region involved in cognition and executive function, are characterized by properties that allow for independent and asynchronous modulation of operations in this area, compared with those that project to the motor cortex and regulate movement generation.”
http://www.pnas.org/content/111/18/6816.full “Heterogeneous organization of the locus coeruleus projections to prefrontal and motor cortices”
