Posts tagged brain
Articles and news from the latest research reports.
Could poor sleep contribute to symptoms of schizophrenia?
Neuroscientists studying the link between poor sleep and schizophrenia have found that irregular sleep patterns and desynchronised brain activity during sleep could trigger some of the disease’s symptoms. The findings, published in the journal Neuron, suggest that these prolonged disturbances might be a cause and not just a consequence of the disorder’s debilitating effects.
The possible link between poor sleep and schizophrenia prompted the research team, led by scientists from the University of Bristol, the Lilly Centre for Cognitive Neuroscience and funded by the Medical Research Council (MRC), to explore the impact of irregular sleep patterns on the brain by recording electrical brain activity in multiple brain regions during sleep.
For many people, sleep deprivation can affect mood, concentration and stress levels. In extreme cases, prolonged sleep deprivation can induce hallucinations, memory loss and confusion all of which are also symptoms associated with schizophrenia.
Dr Ullrich Bartsch, one of the study’s researchers, said: “Sleep disturbances are well-documented in the disease, though often regarded as side effects and poorly understood in terms of their potential to actually trigger its symptoms.”
Using a rat model of the disease, the team’s recordings showed desynchronisation of the waves of activity which normally travel from the front to the back of the brain during deep sleep. In particular the information flow between the hippocampus — involved in memory formation, and the frontal cortex — involved in decision-making, appeared to be disrupted. The team’s findings reported distinct irregular sleep patterns very similar to those observed in schizophrenia patients.
Dr Matt Jones, the lead researcher from the University’s School of Physiology and Pharmacology, added: “Decoupling of brain regions involved in memory formation and decision-making during wakefulness are already implicated in schizophrenia, but decoupling during sleep provides a new mechanistic explanation for the cognitive deficits observed in both the animal model and patients: sleep disturbances might be a cause, not just a consequence of schizophrenia. In fact, abnormal sleep patterns may trigger abnormal brain activity in a range of conditions.”
Cognitive deficits — reduced short term memory and attention span, are typically resistant to medication in patients. The findings from this study provide new angles for neurocognitive therapy in schizophrenia and related psychiatric diseases.
(Source: eurekalert.org)
New brain gene born, study shows
Scientists have taken a step forward in helping to solve one of life’s greatest mysteries - what makes us human?
Image: Irish Wildcat
An international team of researchers have discovered a new gene that helps explain how humans evolved from apes. Scientists say the gene - calledmiR-941 - appears to have played a crucial role in human brain development and may shed light on how we learned to use tools and language. Researchers say it is the first time that a new gene - carried only by humans and not by apes - has been shown to have a specific function within the human body.
Unique finding
A team at the University of Edinburgh compared the human genome to 11 other species of mammals, including chimpanzees, gorillas, mouse and rat, to find the differences between them. The results, published in Nature Communications, showed that the gene - miR-941 - is unique to humans. The researchers say that it emerged between six and one million years ago, after humans had evolved from apes. The gene is highly active in two areas of the brain that control our decision making and language abilities. The study suggests it could have a role in the advanced brain functions that make us human.
Startling results
It is known that most differences between species occur as a result of changes to existing genes, or the duplication and deletion of genes. But scientists say this gene emerged fully functional out of non-coding genetic material, previously termed “junk DNA”, in a startlingly brief interval of evolutionary time. Until now, it has been remarkably difficult to see this process in action. Researcher Dr Martin Taylor, who led the study at the Institute of Genetics and Molecular Medicine at the University of Edinburgh, said the results were fascinating.
This new molecule sprang from nowhere at a time when our species was undergoing dramatic changes: living longer, walking upright, learning how to use tools and how to communicate. We’re now hopeful that we will find more new genes that help show what makes us human. -Dr Martin Taylor (Programme leader, Biomedical Systems Analysis)
(Source: ed.ac.uk)
Naturally, our brain activity waxes and wanes. When listening, this oscillation synchronizes to the sounds we are hearing. Researchers at the Max Planck Institute for Human Cognitive and Brain Sciences have found that this influences the way we listen. Hearing abilities also oscillate and depend on the exact timing of one’s brain rhythms. This discovery that sound, brain, and behaviour are so intimately coupled will help us to learn more about listening abilities in hearing loss.
Watch A French Researcher Control A Robot With His Brain
Researchers in Japan are using a brain-machine interface to control the actions of a humanoid robot. The goal is to allow people “to feel embodied in the body of a humanoid robot,” in the words of one researcher.
Roboticists at the CRNS-AIST Joint Robotics Laboratory, a collaboration between the French National Center for Scientific Research and the Japanese Institute of Advanced Industrial Science and Technology, are trying to interpret brain waves into actions that can be understood by a robot. In the video, a volunteer wears an electrode cap and watches a screen with flashing dots, which is used to teach his brain to associate flickering objects with actions. By focusing his attention, he can induce actions, which are translated from his brain activity into robotic motion.
A signal processing unit on a computer translates his brain activity and classifies it into a series of tasks. Then the team can instruct the robot on which task to perform. It could help paraplegics who can’t perform certain tasks on their own. Or it could be used for crazyfuture tourism, says Abderrahmane Kheddar, director of the JRL: “A paraplegic patient in Rome would be able to pilot a humanoid robot for sightseeing in Japan.”
For brain tumors, origins matter
Cancers arise when a normal cell acquires a mutation in a gene that regulates cellular growth or survival. But the particular cell this mutation happens in—the cell of origin—can have an enormous impact on the behavior of the tumor, and on the strategies used to treat it.
Robert Wechsler-Reya, Ph.D., professor and director of the Tumor Development Program in Sanford-Burnham’s NCI-designated Cancer Center, and his team study medulloblastoma, the most common malignant brain cancer in children. A few years ago, they made an important discovery: medulloblastoma can originate from one of two cell types: 1) stem cells, which can make all the different cell types in the brain or 2) neuronal progenitor cells, which can only make neurons.
Stem cells and progenitor cells are regulated by different growth factors. So, Wechsler-Reya thought, maybe the tumors arising from these cells respond differently to different therapies…
In a study published recently in the journal Oncogene, he and his team show that this is indeed the case. They looked at one growth factor in particular—basic fibroblast growth factor (bFGF)—and found that while it induces stem cell growth, it also inhibits neuronal progenitor cell growth.
What’s more, the researchers discovered that bFGF also blocks the growth of tumors that originate from progenitors. When they treated a mouse model of medulloblastoma with bFGF, it dramatically inhibited tumor growth.
After nearly 10 years of follow-up of study participants who experienced migraines and who had brain lesions indentified via magnetic resonance imaging, women with migraines had a higher prevalence and greater increase of deep white matter hyperintensities (brain lesions) than women without migraines, although the number, frequency, and severity of migraines were not associated with lesion progression, according to a study appearing in the November 14 issue of JAMA. Also, increase in deep white matter hyperintensity volume was not significantly associated with poorer cognitive performance at follow-up.
Migraine affects up to 15 percent of the general population. “A previous cross-sectional study showed an association of migraine with a higher prevalence of magnetic resonance imaging (MRI)-measured ischemic lesions in the brain,” according to background information in the article. White matter hyperintensities are associated with atherosclerotic disease risk factors, increased risk of ischemic stroke, and cognitive decline.
Teenagers’ brains affected by preterm birth
New research at the University of Adelaide has demonstrated that teenagers born prematurely may suffer brain development problems that directly affect their memory and learning abilities.
The research, conducted by Dr Julia Pitcher and Dr Michael Ridding from the University of Adelaide’s Robinson Institute, shows reduced ‘plasticity’ in the brains of teenagers who were born preterm (at or before 37 weeks gestation).
The results of the research are published in the Journal of Neuroscience.
"Plasticity in the brain is vital for learning and memory throughout life," Dr Pitcher says. "It enables the brain to reorganise itself, responding to changes in environment, behaviour and stimuli by modifying the number and strength of connections between neurons and different brain areas. Plasticity is also important for recovery from brain damage.
"We know from past research that preterm-born children often experience motor, cognitive and learning difficulties. The growth of the brain is rapid between 20 and 37 weeks gestation, and being born even mildly preterm appears to subtly but significantly alter brain microstructure, neural connectivity and neurochemistry.
"However, the mechanisms that link this altered brain physiology with behavioural outcomes - such as memory and learning problems - have remained unknown," Dr Pitcher says.
Alzheimer gene may boost young brains but contributes to ‘burnout’ in later years
A gene that confers a higher risk for dementia in old age could also promote better-than-average memory and verbal skills in youth, according to a new University of Sussex-led study.
Neuroscientists tested the cognitive abilities of those with a particular gene variant, known as ‘APOE e4’, found in approximately 25 per cent of the population, against those without it. They also looked at the brain structure and brain activities of both groups during the tasks.
They found that young people with the e4 variant performed better in attention tests (one involving episodic memory of words, the other requiring participants to spot number sequences), which correlated with increased task-related brain activation as detected by MRI scans. The researchers also noticed subtle differences in the white matter of the brains of those with the variant.
Lead researcher Professor Jennifer Rusted said: “Earlier studies suggested that those with the e4 variant outperform those without it in tasks such as memory, speed of processing, mental arithmetic and verbal fluency.
But it is also well-established that this gene is a risk factor for Alzheimer’s disease. The suggestion is that while this confers cognitive advantages in early life, leading to higher achievement, it may also increase susceptibility to memory failure as we enter old age.
“Our study is the first to show that subtle differences in the structure and activation of the brain during cognitive tasks in APOE e4 carriers are linked to their cognitive performance. It is possible that the brain over-activations that we see in youth have negative effects over the longer term and contribute to a kind of ‘burnout’ in older adulthood.”
‘APOE e4 polymorphism in young adults is associated with improved attention andindexed by distinct neural signatures’, by Professor Jennifer Rusted, Dr Simon Evans and Dr Sarah King in the School of Psychology, Dr Nick Dowell and Professor Paul Tofts in the Clinical Imaging Sciences Centre at the Brighton and Sussex Medical School (BSMS), and Dr Najo Tabet in the BSMS Institute of Postgraduate Medicine, is published in NeuroImage.
(Source: sussex.ac.uk)
Seeing someone yawn or hearing someone laugh makes you likely to follow suit. The same goes for scratching an itch. Now, for the first time, researchers have investigated the neural basis of contagious itch, identifying several brain regions whose activity predicts how susceptible people are to feeling itchy when they see someone else scratch.
Researchers in the United Kingdom showed volunteers video clips of people scratching an arm or a spot on their chest. Sure enough, subjects reported feeling more itchy, and most scratched themselves at least once during the experiment. When a subset of the volunteers watched the videos inside an functional magnetic resonance imaging scanner, the scans revealed activity in several of the same brain regions known to fire up in response to an itch-inducing histamine injection.
Activity in three of these areas correlated with subjects’ self-reported itchiness, the team reports online in the Proceedings of the National Academy of Sciences. Personality tests suggest that the trait that best predicts susceptibility to contagious itch is neuroticism, not empathy, as some researchers have suggested.
Meditation appears to produce enduring changes in emotional processing in the brain
A new study has found that participating in an 8-week meditation training program can have measurable effects on how the brain functions even when someone is not actively meditating. In their report in the November issue of Frontiers in Human Neuroscience, investigators at Massachusetts General Hospital (MGH), Boston University (BU), and several other research centers also found differences in those effects based on the specific type of meditation practiced.
"The two different types of meditation training our study participants completed yielded some differences in the response of the amygdala – a part of the brain known for decades to be important for emotion – to images with emotional content," says Gaëlle Desbordes, PhD, a research fellow at the Athinoula A. Martinos Center for Biomedical Imaging at MGH and at the BU Center for Computational Neuroscience and Neural Technology, corresponding author of the report. "This is the first time that meditation training has been shown to affect emotional processing in the brain outside of a meditative state."
Several previous studies have supported the hypothesis that meditation training improves practitioners’ emotional regulation. While neuroimaging studies have found that meditation training appeared to decrease activation of the amygdala – a structure at the base of the brain that is known to have a role in processing memory and emotion – those changes were only observed while study participants were meditating. The current study was designed to test the hypothesis that meditation training could also produce a generalized reduction in amygdala response to emotional stimuli, measurable by functional magnetic resonance imaging (fMRI).