Best and Worst of Neuroscience and Neurology – June 2016by Viatcheslav Wlassoff, PhD | July 15, 2016
This month, a large number of very interesting, sometimes even unexpected discoveries were published. It was hard to prioritise for this review just a few articles out of several dozens of very informative high-quality reports that I’ve seen. As usual, the selection below reflects my personal view on their importance.
In June, the scientific community marked the birthday of Francis Crick who, together with James Watson, received the Nobel Prize in Physiology and Medicine in 1962 for the discovery of DNA structure. The discovery is widely considered as one of the most important in the history of science, and Francis Crick is praised as one of the founding fathers of modern molecular biology and genetics.
Dementia cannot be transmitted via blood transfusion
Ever since discovering that neurodegenerative conditions such as Alzheimer’s and Parkinson’s are caused by aggregation of prion-like proteins, there was a suspicion that the diseases might be transmitted between people via blood transfusion. These fears were convincingly put at rest by new statistical study.
Researchers analysed data from a huge blood transfusion database covering Sweden and Denmark where patients were followed for up to 44 years after receiving blood transfusion. Patients who received the blood from donors later diagnosed with dementia did not have higher chances of developing dementia later in life, compared to control patients who received blood transfusion from healthy donors.
Mechanism behind development of large cerebral cortex in humans discovered
Humans have the largest cerebral cortex of all mammals. This is what sets us apart and makes our brain a powerhouse. However, it was always unclear for scientists how this huge expansion of cerebral cortex occurred in such a short evolutionary time.
The article published this month appears to answer this question. Researchers identified specific long non-coding ribonucleic acid (lncRNA) that regulate neural development. These RNAs trigger a cascade of events leading to the maturation of neurons. Importantly, the identified lncRNA are found only in humans and closely related primates.
Dietary supplement may slow down brain aging
Simple multi-component dietary supplement may dramatically slow down the rate of brain aging, according to researchers from McMaster University, Canada.
The mixture – consisting of common ingredients such as vitamins B, C and D, folic acid, cod liver oil, green tea extract and other nutraceuticals – was shown to prevent and even reverse the signs of brain aging, such as the loss of brain cells, in animal models with accelerated aging. Researchers hope that this simple formulation may be useful in human patients to slow the progress of neurodegenerative diseases such as Alzheimer’s.
Ultra-fast response to fear in human brain
Detection of threats is vitally important to our survival. So it comes as a little surprise that that our brain detects potential threats with ultra-high speed. At least, this is the conclusion of researchers who studied the processing of visual information by the amygdala, which plays a key role in emotional processing.
In the experiments, when human subjects were exposed to the pictures showing fearful faces, the visual signal reached the amygdala directly in 100 milliseconds. More precise, processed signal reached amygdala via neocortex much later. The data show that our brain has a specific mechanism of quickly extracting biologically relevant information.
Beer consumption associated with lower amyloid-beta aggregation in brain
While excessive consumption of alcohol is detrimental to brain health, the effect of moderate drinking is not yet well studied. A new pilot study from Finland suggests that moderate consumption of beer is associated with a lower level of amyloid-beta aggregates forming in the brain. No such association was observed with the consumption of wine or spirits. It still remains unclear if the moderate consumption of beer can be seen as a protective factor against the development of Alzheimer’s disease.
Brain scanner software produces too many false positive results
Analysing fMRI data from brain scanners is a complex task, and a number of assumptions are made to facilitate calculations and shorten the time required to perform them. It appears, however, that simplifications incorporated into the currently used software lead to excessively high percentage of false positive results. This means that the data may show high brain activity in the regions of brain where in reality there is none.
Recent high-profile article published in the Proceedings of the National Academy of Sciences demonstrates where the errors come from and advises a new approach on how to avoid them. In the meantime, researchers warn that the data obtained with the use of older software cannot be fully trusted.
Benefit of remaining uneducated: lower risk of brain cancer
Surprising data on the connection between the level of education and the risk of brain tumor were published this month.
A large observational study based on data from more than 4.3 million people in Sweden demonstrated that men who received at least three years of university education were at 19% higher chances of developing glioma. Among women, this number was even higher (23%), and in addition the educated women were at 16% higher risk of meningioma. Brain tumours were also more common among people in managerial positions. Is ignorance a bliss, after all?
Pregnant American women seriously exposed to chemicals that disrupt brain development
Report published this month suggests that overwhelming majority (90%) of pregnant US women are exposed to chemicals known to disrupt brain development in fetuses. The chemicals include lead and mercury, organophosphate pesticides, phthalates, flame retardants and air pollutants. Some of these compounds, such as phthalates and PBDEs, are known to interfere with normal hormone activity and, in particular, disrupt the function of thyroid hormone which is involved in almost every aspect of brain development. Exposure to phthalates is also linked to attention deficits and lower IQ in children. The authors call for the review of current regulations to prevent the exposure to these chemicals.
Use of antidepressants is ineffective and might be unsafe in children and teens
The use of antidepressants in children and teenagers is a controversial issue. A recent meta-analysis of 34 trials indicates that most available antidepressants are not effective. Moreover, they might be even dangerous. The authors analysed 14 drugs and found no evidences to support their effectiveness at relieving the symptoms of depression, with the exception of fluoxetine. Venlafaxine was shown to increase the risk of suicidal thoughts.
The authors call to rethink current strategies of using antidepressant drugs in this population. According to them, there are no reasons to think that using antidepressants is better than doing nothing when a child suffers from depression.
Use of antidepressants by pregnant women affect the newborns’ brain
Yet another “anti-antidepressant” article was published this month: it turned out that the use of antidepressants such as serotonin re-uptake inhibitors (SRIs) by pregnant women affects the brain activity of newborn babies. Specifically, the newborns whose mothers used SRIs have less-organized communication between brain hemispheres and weaker synchronization between cortical rhythms.
The findings add weight to the previous reports on potential side effects of SRIs during pregnancy. Since SRIs are used by around 5% of pregnant women, the findings should be taken seriously by the medical community.
Bennett, D., Bellinger, D., Birnbaum, L., Bradman, A., Chen, A., Cory-Slechta, D., Engel, S., Fallin, M., Halladay, A., Hauser, R., Hertz-Picciotto, I., Kwiatkowski, C., Lanphear, B., Marquez, E., Marty, M., McPartland, J., Newschaffer, C., Payne-Sturges, D., Patisaul, H., Perera, F., Ritz, B., Sass, J., Schantz, S., Webster, T., Whyatt, R., Woodruff, T., Zoeller, R., Anderko, L., Campbell, C., Conry, J., DeNicola, N., Gould, R., Hirtz, D., Huffling, K., Landrigan, P., Lavin, A., Miller, M., Mitchell, M., Rubin, L., Schettler, T., Tran, H., Acosta, A., Brody, C., Miller, E., Miller, P., Swanson, M., Witherspoon, N., , ., , ., , ., , ., , ., , ., , ., , ., & , . (2016). Project TENDR: Targeting Environmental Neuro-Developmental Risks The TENDR Consensus Statement Environmental Health Perspectives, 124 (7) DOI: 10.1289/EHP358
Cipriani, A., Zhou, X., Del Giovane, C., Hetrick, S., Qin, B., Whittington, C., Coghill, D., Zhang, Y., Hazell, P., Leucht, S., Cuijpers, P., Pu, J., Cohen, D., Ravindran, A., Liu, Y., Michael, K., Yang, L., Liu, L., & Xie, P. (2016). Comparative efficacy and tolerability of antidepressants for major depressive disorder in children and adolescents: a network meta-analysis The Lancet DOI: 10.1016/S0140-6736(16)30385-3
Edgren, G., Hjalgrim, H., Rostgaard, K., Lambert, P., Wikman, A., Norda, R., Titlestad, K., Erikstrup, C., Ullum, H., Melbye, M., Busch, M., & Nyrén, O. (2016). Transmission of Neurodegenerative Disorders Through Blood Transfusion Annals of Internal Medicine DOI: 10.7326/M15-2421
Eklund, A., Nichols, T., & Knutsson, H. (2016). Cluster failure: Why fMRI inferences for spatial extent have inflated false-positive rates Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1602413113
Khanolkar, A., Ljung, R., Talbäck, M., Brooke, H., Carlsson, S., Mathiesen, T., & Feychting, M. (2016). Socioeconomic position and the risk of brain tumour: a Swedish national population-based cohort study Journal of Epidemiology and Community Health DOI: 10.1136/jech-2015-207002
Kok, E., Karppinen, T., Luoto, T., Alafuzoff, I., & Karhunen, P. (2016). Beer Drinking Associates with Lower Burden of Amyloid Beta Aggregation in the Brain: Helsinki Sudden Death Series Alcoholism: Clinical and Experimental Research, 40 (7), 1473-1478 DOI: 10.1111/acer.13102
Lemon, J., Aksenov, V., Samigullina, R., Aksenov, S., Rodgers, W., Rollo, C., & Boreham, D. (2016). A multi-ingredient dietary supplement abolishes large-scale brain cell loss, improves sensory function, and prevents neuronal atrophy in aging mice Environmental and Molecular Mutagenesis, 57 (5), 382-404 DOI: 10.1002/em.22019
Méndez-Bértolo, C., Moratti, S., Toledano, R., Lopez-Sosa, F., Martínez-Alvarez, R., Mah, Y., Vuilleumier, P., Gil-Nagel, A., & Strange, B. (2016). A fast pathway for fear in human amygdala Nature Neuroscience DOI: 10.1038/nn.4324
Rani, N., Nowakowski, T., Zhou, H., Godshalk, S., Lisi, V., Kriegstein, A., & Kosik, K. (2016). A Primate lncRNA Mediates Notch Signaling during Neuronal Development by Sequestering miRNA Neuron, 90 (6), 1174-1188 DOI: 10.1016/j.neuron.2016.05.005
Videman, M., Tokariev, A., Saikkonen, H., Stjerna, S., Heiskala, H., Mantere, O., & Vanhatalo, S. (2016). Newborn Brain Function Is Affected by Fetal Exposure to Maternal Serotonin Reuptake Inhibitors Cerebral Cortex DOI: 10.1093/cercor/bhw153
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