Posts tagged neuroscience
Articles and news from the latest research reports.
This is how a heart becomes a heart
A “synchronised dance” of thousands of genes generates a healthy heart, but one faux pas may result in congenital heart defects.
Congenital heart defects (CHD) are one of the most common birth abnormalities in the world. In Australia six babies are born with a heart disease every day and more than 32,000 children under the age of 18 live with a CHD, but a team of researchers at the Gladstone Institutes have found the genetic switches that translate as a functional heart.
Using next-generation DNA sequencing and stem cell technology, the researchers were able to decipher the genomic blueprint (the instruction manual) of a heart. The finding will help understand how certain CHDs such as holes in the heart (septal defects) are formed. “Congenital heart defects are the most common type of birth defects,” said Gladstone Senior Investigator Benoit Bruneau to UCFS news. “But how these defects develop at the genetic level has been difficult to pinpoint because research has focused on a small set of genes. Here, we approach heart formation with a wide-angle lens by looking at the entirety of the genetic material that gives heart cells their unique identity.”
A glance at a star-nosed mole (Condylura cristata) is enough to convince most people that something very strange has evolved in the bogs and wetlands of North America. There’s nothing else on the planet quite like this little palm-sized mammal. Its nose is ringed by 22 fleshy appendages, called rays, which are engorged with blood and in a constant flurry of motion when the animal searches for food.
What is this star? How did it evolve and what is it for? What advantage would be worth sporting such an ungainly structure? To a neuroscientist interested in sensory systems, this kind of biological anomaly represents an irresistible mystery. I first began studying star-nosed moles in the early ’90s in an attempt to answer some of these basic questions. But I soon discovered that this unusual animal, like many other specialized species, could reveal general principles about how brains process and represent sensory information. In fact, star-nosed moles have been a gold mine for discoveries about brains and behavior in general—and an unending source of surprises. The most obvious place to start the investigation was with that bizarre star.
(Source: the-scientist.com)
Learning faster with neurodegenerative disease
People who bear the genetic mutation for Huntington’s disease learn faster than healthy people. The more pronounced the mutation was, the more quickly they learned. This is reported by researchers from the Ruhr-Universität Bochum and from Dortmund in the journal Current Biology. The team has thus demonstrated for the first time that neurodegenerative diseases can go hand in hand with increased learning efficiency. “It is possible that the same mechanisms that lead to the degenerative changes in the central nervous system also cause the considerably better learning efficiency” says Dr. Christian Beste, head of the Emmy Noether Junior Research Group “Neuronal Mechanisms of Action Control” at the RUB.
Passive learning through repeated stimulus presentation
In a previous study, the Bochum psychologists reported that the human sense of vision can be changed in the long term by repeatedly exposing subjects to certain visual stimuli for short periods (we reported in May 2011). The task of the participants was to detect changes in the brightness of stimuli. They performed better if they had viewed the stimuli passively for a while first. In the current study, the researchers presented the same task to 29 subjects with the genetic mutation for Huntington’s disease, who, however, did not yet show any symptoms. They also tested 45 control subjects without such mutations in the genome. In both groups, the learning efficiency was better after passive stimulus presentation than without the passive training. Subjects with the Huntington’s mutation, however, increased their performance twice as fast as those without the mutation.
Glutamate may have paradoxical effect
Degenerative diseases of the nervous system are based on complex changes. A key mechanism is an increased release of the neurotransmitter glutamate. However, since glutamate is also important for learning, in some cases it could lead to the paradoxical effect: better learning efficiency despite degeneration of the nerve cells.
Detecting differences in brightness under aggravated conditions
In each experimental run, the subjects saw two consecutive small bars on a computer screen that either had the same or different brightness. Sometimes, however, not only the brightness changed from bar one to bar two, but also the orientation of the bar (vertical or horizontal). “Normally, the distraction stimulus, i.e. the change in orientation, draws all the attention” Christian Beste explains. “But after the passive training with the visual stimuli, the distraction stimulus has no effect at all.” The shift of attention from the non-relevant to the relevant properties of the stimulus was also visible in the electroencephalogram (EEG) in brain areas for early visual processing.
Better performance with stronger mutation
In Huntington’s disease, a short segment of a gene is repeated. The number of repetitions determines when the disease breaks out. In the present study, a greater number of repetitions was, however, also associated with higher learning efficiency. “This shows that neurodegenerative changes can cause paradoxical effects” says Christian Beste. “The everyday view that neurodegenerative changes fundamentally entail deterioration of various functions can no longer be maintained in this dogmatic form.”
(Source: aktuell.ruhr-uni-bochum.de)
Animation of bionic eye being developed in Melbourne, Australia by the Bionic Vision Australia consortium.
A new study shows that newborns that have been exposed to nicotine from both active and passive smoking mothers show poor physiological, sensory, motor and attention responses.
"Newborns who have had intrauterine exposure to nicotine, whether in an active or passive way, show signs of being more affected in terms of their neurobehavioural development. This could be an indicator of pathologies, independently of sociodemographic, obstetric and paediatric factors," as explained to SINC by Josefa Canals and Carmen Hernández, the lead authors of the study.
Using ultrasound waves, MIT engineers have found a way to enhance the permeability of skin to drugs, making transdermal drug delivery more efficient. This technology could pave the way for noninvasive drug delivery or needle-free vaccinations, according to the researchers.
“This could be used for topical drugs such as steroids — cortisol, for example — systemic drugs and proteins such as insulin, as well as antigens for vaccination, among many other things,” says Carl Schoellhammer, an MIT graduate student in chemical engineering and one of the lead authors of a recent paper on the new system.
Ultrasound — sound waves with frequencies greater than the upper limit of human hearing — can increase skin permeability by lightly wearing away the top layer of the skin, an effect that is transient and pain-free.
In a paper appearing in the Journal of Controlled Release, the research team found that applying two separate beams of ultrasound waves — one of low frequency and one of high frequency — can uniformly boost permeability across a region of skin more rapidly than using a single beam of ultrasound waves.
The most common form of strokes are caused by a sudden reduction in blood flow to the brain (ischemia) that leads to an inadequate supply of oxygen and nutrients. These so-called ischemic strokes are one of the leading causes of death and disability in industrialized nations. If they are not immediately remedied by medical intervention, areas of the brain may die off. In the journal Angewandte Chemie, Korean researchers have now proposed a new approach for supplemental treatment: Ceria nanoparticles could trap the reactive oxygen compounds that result from ischemia and cause cells to die.
Nanoengineers at the University of California, San Diego have developed a novel technology that can fabricate, in mere seconds, microscale three dimensional (3D) structures out of soft, biocompatible hydrogels. Near term, the technology could lead to better systems for growing and studying cells, including stem cells, in the laboratory. Long-term, the goal is to be able to print biological tissues for regenerative medicine. For example, in the future, doctors may repair the damage caused by heart attack by replacing it with tissue that rolled off of a printer.
The biofabrication technique uses a computer projection system and precisely controlled micromirrors to shine light on a selected area of a solution containing photo-sensitive biopolymers and cells. This photo-induced solidification process forms one layer of solid structure at a time, but in a continuous fashion.
A syndrome called “post-operative cognitive decline” has been coined to refer to the commonly reported loss of cognitive abilities, usually in older adults, in the days to weeks after surgery. In fact, some patients time the onset of their Alzheimer’s disease symptoms from a surgical procedure. Exactly how the trio of anesthesia, surgery, and dementia interact is clinically inconclusive, yet of great concern to patients, their families and physicians.
A year ago, researchers at the Perelman School of Medicine at the University of Pennsylvania reported that Alzheimer’s pathology, as reflected by cerebral spinal fluid biomarkers, might be increased in patients after surgery and anesthesia. However, it is not clear whether the anesthetic drugs or the surgical procedure itself was responsible. To separate these possibilities, the group turned to a mouse model of Alzheimer’s disease.
The results, published online this month in the Annals of Surgery, show that surgery itself, rather than anesthesia, has the more profound impact on a dementia-vulnerable brain.