The findings are the latest to suggest that these universally fatal, if rare, diseases can be spread through the eyes.
We can get sick from prions in a few ways. Sometimes, people are born with mutations passed down in their family that increase the risk of developing a prion disease, including a form of CJD. Most commonly, as with people who have sCJD, the prions show up spontaneously, with the normally harmless prion protein changing into a misfolded form that makes nearby proteins misfold, too. But what’s especially terrifying about prions is that they can also be infectious, capable of spreading from person to person, or even animal to person.
It can take years, even decades, for the symptoms of a prion disease (such as dementia or muscle weakness) to show up, but once they do, it’s usually only a matter of months before death.
Conley describes his early academic work as “lefty sociology.” His Ph.D. thesis was on the black-white wealth gap and he dedicated his early career to studying the transmission of health and wealth between parents and children.
At N.Y.U., Conley kept getting into disagreements with geneticists, arguing that their methods were dangerously naïve. It seemed to him implausible that studying only twins — the gold standard of genetics research — was enough to teach us the difference between nature and nurture. But over time, he decided that it wasn’t enough to just argue.
Conley is an academic, and even within that tortured group he is something of a masochist. At that time he was a tenured professor, the kind of gig most people see as the endgame of an academic career, and yet he decided to go back and grind out another Ph.D., this time in genetics. He went into his program believing that our social environment is largely the cause of our outcomes, and that biology is usually the dependent variable.
By the end of his time, he says, the causal arrow in his mind had pretty much flipped the other way: “I tried to show for a range of outcomes that the genetic models were overstating the impact of genetics because of their crazy assumptions.” He sighs. “But I ended up showing that they’re right.”
WE ALL have memories we would rather forget – and it is possible, if you try hard enough.
It is easy to think of memories as something you can actively strengthen, whereas forgetting is a passive process. But we have started to discover it can be intentional too.
Perhaps the easiest way to forget something is simply to try to suppress a memory. Jeremy Manning at Dartmouth College, New Hampshire, has found that just telling people to “push thoughts out of their head” is enough to make them forget lists of words they have learned to associate with particular cues. “We don’t know how, but people seem to know how to do it.”
The truth about memory is far more elaborate than we previously thought. Here’s your guide to how it really works
This seems especially paradoxical because we also know that rehearsing memories helps to strengthen them. Suppression has been linked to decreased activity in the hippocampus, so we may be unknowingly reducing our hippocampal activity by focusing on the present, says Justin Hulbert at Bard College, New York.
Doctors in the UK will be able to prescribe cannabis products to patients from 1 November, Home Secretary Sajid Javid has announced.
Javid had decided to relax the rules about the circumstances in which cannabis products can be given to patients, after considering expert advice from a specially commissioned review.
The new regulations apply to England, Wales and Scotland, and follow several high-profile cases, including that of Alfie Dingley and Billy Caldwell, children with epilepsy whose conditions appeared to be helped by cannabis oïl.
A recent study of enterochromaffin cells, a subset of enteroendocrine cells, also found that gut signals are transmitted at epithelial-neural synapses through release of the neurotransmitter serotonin (4). Together, these findings overturn a decades-old dogma that enteroendocrine cells signal exclusively through hormones.
Doctors in the UK should be able to prescribe cannabis-derived medicine, the government’s chief drug advisers have recommended, paving the way for a loosening of the laws governing access to the substance.
Cannabis is classed as a schedule 1 drug, meaning it is thought to have no therapeutic value and cannot be lawfully possessed or prescribed. It may be used for the purposes of research but a Home Office licence is required.
“At present, cannabis-derived products can vary greatly in their composition, effectiveness and level of impurity. It is important that clinicians, patients and their families are confident that any prescribed medication is both safe and effective.”
The ACMD has tasked the Department of Health and Social Care and the Medicines and Healthcare products Regulatory Agency with producing a definition for the products that could be prescribed.
The council also recommends that clinical trials urgently take place to further establish the safety and effectiveness of different products.
In 2017, scientists managed to observe and produce the loving mechanism to voles of prairies1. Before going further in this article, it is necessary to know that this species (Microtus ochrogaster) is curiously an excellent choice to model the human loving behavior. Indeed, voles look like us emotionally talking: they are monogamous but have sexual interactions with other partners than their other half, they become aggressive in the presence of other individuals of the same sex and depressed when they lose their partner. Furthermore, the prefrontal cortex of voles and humans can modify the behavior of the deep layers of the brain.
That’s what happens to the voles when they fall in love… and thus that’s probably what happens to us either in such a situation. The neuroscientists of the Emory University of Atlanta were able to observe that the loving feeling coincides, in the brain of voles, with the takeover of the accumbens core by the prefrontal cortex. In other words, the center of reflection and decision suddenly takes over the center of pleasure while the subject falls in love. It would thus be the intellect which would be at the origin of the Love feeling! And it would be it which would make us perceive the presence of our partner as a reward.
The same team was able to verify it: having introduced photoperceptible genes into certain neurons of a female, they put her in a cage with an unknown male (and they made sure to prevent any physical contact between them). Then they activated the neurons of the prefrontal cortex of the female with a frequency determined during preliminary phases of observation, before the experiment. Then they placed the female in an environment containing various males: in 10 cases out of 12, the female then preferred the male that was chosen by the scientists.
Even if this behavior are not directly transposable to a human (whose brain is more complex), this experiment lights us on the way we work. And, potentially, this knowledge can help us treating disorders as autism, which corresponds to a difficulty in creating social links.
1■ Science et vie, august 2017, “Les secrets de l’amour enfin révélés” [“Science and life”, “Secrets of loved finally uncovered”]
Is it possible to enhance and rewire the adult brain?
To find out more about plasticity in the brain, host Nicola Davis speaks to Dr Tamar Makin, a neuroscientist at the University of College London’s Institute of Cognitive Neuroscience; Nick Ward, a professor of neurology and neurorehabilitation at University College London; and Prof Allan Young, chair of mood disorders at King’s College London and a coauthor of a recent study into possible drug treatments to enhance brain plasticity.
In attempts to define what makes us uniquely human, emotions and feelings are often marginalized. These deeply ingrained, often irrational aspects of our behaviour seem destined to be the poor cousins of the rational cognitive functions that enable the formulation of mathematical theorems or operatic scores. In his bold and important book The Strange Order of Things, neuroscientist Antonio Damasio argues that in underestimating the contributions of such ‘lower-level’ brain phenomena to ‘higher-level’ cognitive functions, science might have been missing out on some important biology. Similarly, neuroscience’s emphasis on the origins of language as a shaper of culture might have eclipsed the role of feelings.
Damasio traces core components of the human “cultural mind”, such as social behaviour and cooperation, back to the non-human biology of unicellular organisms present at the inception of life. Bacteria do not sit up at night to contemplate the nature of their existence, and are unable to calculate the trajectories of distant planets. Nevertheless, they are in full command of an impressive repertoire of social behaviours. For example, when nutrients are scarce, bacteria eschew their hermit-like lives and clump together. They can also align into defensive palisades that can confer resistance to antibiotics.
Although compelling and refreshingly original, Damasio’s thesis would have benefited from a more detailed exposition of the scientific evidence supporting his assertions.
Chemical controllers: How hormones influence your body and mind
WE LIKE to think we are in charge of our own behaviour – that our thoughts are under our conscious control and that our actions are mostly reasonable. But our behaviour is also in the sway of an ancient system of mind control: hormones. These protein messengers are best known for their fundamental duty as regulators – think of insulin and blood sugar, for example – but they also bathe the brain in chemical information that tells us about the world around us and the people in it.
Can a surge in a particular hormone make us feel and act like a totally different person?
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Nowadays, science verifies more and more this old proverb. Indeed, we begin to realize the enormous influence that our food has on our physical and mental health, on our feelings and our way of thinking.
Why? Because the food we gulp down has contact with our digestive system, which is a kind of … a second brain. That could sound strange, but sometimes reality does: not only our digestive system contains neurons, but it contains nothing less than 100 milliards of them1! Connected between them and also with the brain, the one which stands in the head, via the vagus nerve, of which between 80 % and 90 % of fibers are none-reciprocal, and let information pass from the stomach (in particular the small intestine, around which it is rolled up) to the brain2. So it is our digestive system which tells our brain how to behave, and not the opposite!
We thus very well understand that what we eat influences our digestive system, and thus our brain: our feelings, our reflections, etc.
Furthermore, our food also has a direct effect on our intestinal flora, these 100000 billion of small bacteria which develop in our digestive system. But this intestinal flora, which has a very important effect on our body, depends naturally on our food. And from its composition can ensue cardiovascular risks4, anxiety and dépression2, autism4, obesity4, neurological diseases (as the Parkinson’s disease5), diabetes4, cancer4, as well as disorders in our hormonal and immune systems 2.
A research team led by Mark Kahn, of the university of Pennsylvania, showed that the risk of developing cavernomes (vascular malformations resulting in risks of brain haemorrhages) depended on the intestinal flora of an individual. To prove that, they identified certain bacteria of the intestinal flora of mouse freeing a toxin susceptible to cross into the body and to generate cavernomes. By preventing the fixation of this toxin in the body of mice, they managed to reduce of 90 % the development of cavernomes in the population of studied mouse, proving the direct link between intestinal flora and appearance of cavernomes.3
Researchers showed the link between intestinal flora and Parkinson’s disease by transplanting the intestinal flora of sick mice in healthy mice, what made reveal the symptoms of the disease in the sane mice. On the other hand, by isolating sick mice in a sterile environment or by treating them with antibiotics (and doing so by eliminating their intestinal flora), the researchers managed to reduce the intensity of the symptoms of the disease.5
A research team led by Floris Fransen identified that the intestinal flora of young individuals differed from that of the old ones. And by transferring the intestinal microbiote of old individuals in young individuals, and vice versa, they managed in a case to generate disorders to the guinea pig and to reduce them in the other one.4
Professor P. Holzer, neuro-gastroenterologist from Graz’s Hospital, was able to observe during large-scale epidemiological studies led on volunteers, that food has an effect on the humor of people, as they eat healthily or not.3
WHAT CAN BE DONE WITH IT
These discoveries are a real revolution: they actually allow to envisage in the future to handle a lot of complex diseases simply by modifying the intestinal flora of the sick person, using for example antibiotics or probiotics.
Well, as prevention is better than cure, pay attention on what you eat!