Posts tagged neuroscience
Articles and news from the latest research reports.
High quality Denisovan genome sheds light on human evolution: Sequencing our extinct relatives let us know how we differ from chimps.
The discovery that a second branch of the human family shared Asia with our ancestors and the Neanderthals was a real shock, but the Denisovans have continued to surprise many. All we have of them is a bit of a finger and some molars, but those few fragments have yielded a wealth of DNA, and with it the knowledge that the Denisovans interbred with the ancestors of some modern human populations. Now, with the help of a new approach to sequencing ancient DNA, we actually know more about the Denisovans’ genome than we do about Neanderthals’. In the process, we’ve discovered some of the changes that are distinct to modern humans.
Adding to the mounting evidence that consuming moderate amounts of chocoloate may benefit the heart, comes that of a new study of Swedish men that suggests it may also lower the risk of stroke.
Med Sensation's Glove Tricorder is outfitted with numerous sensors to detect breast cancer and other internal medical problems when placed on different areas of the body.
Are you addicted to the Internet? You might be able to blame your genes.
Scientists say they’ve found a link between a toxic relationship with the Web and a genetic quirk that also plays a role in nicotine addiction.
Researchers at the University of Bonn in Germany interviewed 843 people about their online habits. Of them, 132 showed signs of an unhealthy relationship with the Internet — all of their thoughts revolved around it and their sense of wellbeing was shaken if they couldn’t go online. By comparing the genes of the two groups, the researchers found the subset of likely Internet addicts more often carried a mutation the CHRNA4 gene, which is typically linked to nicotine addiction.
Re-opening Windows: Manipulating Critical Periods for Brain Development
The brain acquires certain skills—from visual perception to language—during critical windows, specific times in early life when the brain is actively shaped by environmental input. Scientists like Takao K. Hensch are now discovering pathways in animal models through which these windows might be re-opened in adults, thus re-awakening a brain’s youth-like plasticity. Such research has implications for brain injury repair, sensory recovery, and neurodevelopmental disorder treatment. In addition, what we know today about these critical windows of development already has enormous implications for social and educational policy.
On the topic of computers, artificial intelligence and robots, Northern Illinois University Professor David Gunkel says science fiction is fast becoming “science fact.”
Fictional depictions of artificial intelligence have run the gamut from the loyal Robot in “Lost in Space” to the killer computer HAL in “2001: A Space Odyssey” and the endearing C-3PO and R2-D2 of “Star Wars” fame.
While those robotic personifications are still the stuff of fiction, the issues they raised have never been more relevant than today, says Gunkel, an NIU Presidential Teaching Professor in the Department of Communication.
In his new book, “The Machine Question: Critical Perspectives on AI, Robots, and Ethics” (The MIT Press), Gunkel ratchets up the debate over whether and to what extent intelligent and autonomous machines of our own making can be considered to have legitimate moral responsibilities and any legitimate claim to moral treatment.
Standard head movements made while exposed to one of the three electromagnetic fields produced by a heavy duty MRI scanner seem to temporarily lower concentration and visuospatial awareness, shows an experimental study published online in Occupational and Environmental Medicine.
Thirty one volunteers made standard head movements within the static magnetic field of a higher field 7 Tesla MRI scanner at exposure levels of zero (sham), 0.5 (medium), and 1 (high)Tesla, in a random order, one week apart.
After each exposure level, the volunteers were set 12 timed cognitive tasks, designed to test the sorts of skills that a surgeon or other healthcare professional might need to deploy within the vicinity of an MRI scanner.
These included visual tracking and movement, as well as more general functions, such as attention, concentration and working memory. The tests were neutral in that they didn’t test intelligence or depend on practice.
In all, 30 volunteers completed all three sessions. Compared with the sham test, the results showed that the more general functions, such as attention and concentration, and visuospatial awareness were significantly affected.
Lubricated nanoparticles penetrate the brain
Nanoparticles often meet a sticky end in the brain. In theory, the tiny structures could deliver therapeutic drugs to a brain tumour, but navigating the narrow, syrupy spaces between brain cells is difficult. A spot of lubrication could help.
Nanoparticles (green) coated with poly(ethylene-glycol) (PEG) (Image: Elizabeth Nance, Graeme Woodworth, Kurt Sailor)
Justin Hanes at Johns Hopkins University in Baltimore, Maryland, was surprised to discover just how impermeable brain tissue is to nanoparticles. “It’s very sticky stuff,” he says, similar in adhesiveness to mucus, which protects parts of the body – such as the respiratory system – by trapping foreign particles.
It was thought that the adhesiveness of brain tissue limited the size of particles that can smoothly spread through the brain. Signalling molecules, nutrients and waste products below 64 nanometres in diameter can pass through the tissue with relative ease, but larger nanoparticles – suitable for delivering a payload of drugs to a specific location in the brain – quickly get stuck.
Now Hanes and his colleagues have doubled that size limit. They coated their nanoparticles with a densely-packed polymer shield, which lubricates their surface by preventing electrostatic and hydrophobic interactions with the surrounding tissue. “A nice hydrated shell around the particle prevents it from adhering to cells,” says Hanes.
Tracking the particles
Using this approach, they were able to observe the diffusion of nanoparticles 114 nanometres in diameter through live mouse brains and dissected human and rat brain tissue. Hanes believes the true upper size limit now lies somewhere between 114 nm and 200 nm. “Things were starting to slow down at 114,” he says.
But further research is needed before the team can progress to clinical trials in humans. “At this scale, it is very important to understand where our nanoparticles go once injected into the body,” says team member Elizabeth Nance, also of Johns Hopkins University. “We will need to show that, when combined with a therapeutic agent, these particles are getting to our site of interest, are having the intended effect and are not causing any side effects or toxicity to healthy normal tissue.”
"The effect of this work should be long-term," says Paul Wilson at the University of Warwick in Coventry, UK. The result represents significant progress in the battle to administer drugs within the brain, he says. "More effective and longer-lasting treatments against brain diseases, such as tumours and strokes, will no doubt soon follow."
Source: NewScientist
Alzheimer’s triggered by “type three diabetes”
An unhealthy diet could lead to Alzheimer’s disease by triggering a form of insulin resistance dubbed “type three diabetes”, scientists claim.
Photo: Getty Images/Peter Macdiarmid
High levels of the hormone insulin, brought on by a bad diet, may harm the brain in the same way that the muscle, liver and fat cells are affected by type two diabetes. Exposing the brain to too much insulin could cause it to stop responding to the hormone, hampering our ability to think and create new memories and ultimately leading to permanent damage, researchers said.
A diet high in fat and sugar has long been linked to a higher risk of Alzheimer’s, while studies of health among large populations have shown that a healthy Mediterranean diet may offer some protection. In type two diabetes, eating too much fatty and sugary food raises our insulin levels to such a consistently high degree that our muscles, fat and liver cells are no longer affected by the hormone.
This means that the amount of glucose and fat in our blood is allowed to increase unchecked, forcing the pancreas to produce even more insulin to try to cope. Ultimately it becomes exhausted and production drops to very low levels.
A small-scale trial on human patients at Washington University found that those who were given a nasal spray containing insulin were better at remembering details of stories, had longer attention spans and were more independent. A further trial on 240 volunteers showing early signs of dementia will provide further clues as to whether the spray can protect memory and learning ability and keep track of brain changes in patients.
A study on rats by experts from Brown University suggest that a similar process could affect the brain, which relies on insulin to regulate nerve signals related to memory and learning and to produce energy from glucose. Researchers found that blocking insulin from rats’ brains made them disorientated and unable to find their way out of a maze because they could not remember where they were.
Examination of their brains showed the same pattern of deterioration seen in Alzheimer’s patients, including increased levels of the amyloid plaque which is a key hallmark of the condition. If the theory is correct, it means eating more healthy foods and exercising more could reduce the risk of Alzheimer’s, and potentially reverse or slow down the memory loss in patients with the condition.
Dr Suzanne de la Monte, who led the study, told New Scientist magazine: “[The rats] were demented. They couldn’t learn or remember. “I believe [Alzheimer’s] starts with insulin resistance. If you can avoid brain diabetes you’ll be fine. But once it gets going you are going to need to attack on multiple fronts.”
(Source: telegraph.co.uk)
Expectant mothers are used to fuzzy images on ultrasound monitors and blood tests to screen for potential health problems in their unborn babies. But what if one of those blood tests came back with a readout of the baby’s entire genome? What if a simple test gave parents every nuance of a baby’s genetic makeup before birth?
Recent studies show that it’s possible to decode an entire fetal genome from a sample of the mother’s blood. In the future, doctors may be able to divine a wealth of information about genetic diseases or other characteristics of a fetus from the pregnant mother’s blood. Such tests will raise ethical questions about how to act on such information. But they could also lead to research on treating diseases before birth, and leave parents and their doctors better prepared to care for babies after birth.