Posts tagged brain
Articles and news from the latest research reports.
Rewired visual input to sound-processing part of the brain leads to compromised hearing
Scientists at Georgia State University have found that the ability to hear is lessened when, as a result of injury, a region of the brain responsible for processing sounds receives both visual and auditory inputs.
Yu-Ting Mao, a former graduate student under Sarah L. Pallas, professor of neuroscience, explored how the brain’s ability to change, or neuroplasticity, affected the brain’s ability to process sounds when both visual and auditory information is sent to the auditory thalamus.
The study was published in the Journal of Neuroscience.
The auditory thalamus is the region of the brain responsible for carrying sound information to the auditory cortex, where sound is processed in detail.
When a person or animal loses input from one of the senses, such as hearing, the region of the brain that processes that information does not become inactive, but instead gets rewired with input from other sensory systems.
In the case of this study, early brain injury resulted in visual inputs into the auditory thalamus, which altered how the auditory cortex processes sounds.
The cortical “map” for discriminating different sound frequencies was significantly disrupted, she explained.
“One of the possible reasons the sound frequency map is so disrupted is that visual responsive neurons are sprinkled here and there, and we also have a lot of single neurons that respond to both light and sound,” Pallas said. “So those strange neurons sprinkled there probably keeps the map from forming properly.”
Mao also discovered reduced sensitivity and slower responses of neurons in the auditory cortex to sound.
Finally, the neurons in the auditory cortex were less sharply tuned to different frequencies of sound.
“Generally, individual neurons will be pretty sensitive to one sound frequency that we call their ‘best frequency,’” Pallas said. “We found that they would respond to a broader range of frequencies after the rewiring with visual inputs.”
While Pallas’ research seeks to create a basic understanding of brain development, knowledge gained from her lab’s studies may help to give persons who are deaf, blind, or have suffered brain injuries ways to keep visual and auditory functions from being compromised.
“Usually we think of plasticity as a good thing, but in this case, it’s a bad thing,” she said. “We would like to limit the plasticity so that we can keep the function that’s supposed to be there.”
Source: Georgia State University
Using bioluminescent proteins from a jellyfish, a team of scientists has lit up the inside of a neuron, capturing spectacular video footage that shows the movement of proteins throughout the cell.
(Source: medicalxpress.com)
With his knack for knowing what stem cells want, Yoshiki Sasai has grown an eye and parts of a brain in a dish.
All it took to grow a retina, it turned out, were a few tweaks, such as a reduction in the concentration of growth factors and the addition of a standard cell-culture ingredient called Matrigel. The result closely mimics eye development in the embryo. By the sixth day in culture, the brain balls start sprouting balloon-like growths of retinal cells, which then collapse in on themselves to make the double-walled optic cups. Sasai’s team snip them off — “like taking an apple from a tree”, says Sasai — transfer them to a different culture and let them be. Two weeks later, the cups have formed all six layers of the retina, an architecture that resembles the eye of an 8-day-old mouse (which, at that age, is still blind). That the cells could drive themselves through this dramatic biomechanical process without surrounding tissues to support them stunned Sasai as much as anyone else. “When I saw it, I thought, ‘Oh my god.’ Shape, topology and size are all recapitulated,” he says. Carefully explaining the pun to come, he adds: “In English, when you are surprised, you say ‘eye-popping’ — so we really thought this was eye-popping.”
(Source: nature.com)
Necomimi feature NeuroSky’s brain-computer interface technology to control the motion of the cat ears. The latest product sporting the company’s brainwave-reading technology features a slightly more fun form factor – fluffy, wearable cat ears that move in response to the wearer’s emotional state.
Researchers at the University of Iowa studied the brain of a patient with rare, severe damage to three regions long considered integral to self-awareness in humans (from left to right: the insular cortex, anterior cingulate cortex, and the medial prefrontal cortex). Based on the scans, the UI team believes self-awareness is a product of a diffuse patchwork of pathways in the brain rather than confined to specific areas.
Stem Cell Trial for Autism Launches in U.S.
August 21, 2012
Stem cell treatment could lower inflammation levels and demonstrate whether autism is an autoimmune disease
Image: Nature News
Families with autistic children must navigate a condition where questions outnumber the answers, and therapies remain sparse and largely ineffective. A clinical trial being conducted by the Sutter Neuroscience Institute in Sacramento, California to address this situation began recruiting participants today for a highly experimental stem cell therapy for autism. The institute plans to find 30 autistic children between ages 2 and 7 with cord blood banked at the privately-run Cord Blood Registry, located about 100 miles west of the institute. Already one other clinical trial, with 37 total participants between ages 3 and 12 years old, has been completed in China. The researchers affiliated with Beike Biotechnology in Shenzhen, the firm that sponsored the study, have not yet published any papers from that the trial, which used stem cells from donated cord blood. Mexican researchers are currently recruiting kids for yet another type of autism stem cell trial that will harvest cells from the participant’s fat tissue.
But for each of these officially registered trials, many more undocumented stem cell therapy treatments take place for clients who are willing to pay enough. “Our research is important because many people are going to foreign countries and spending a lot of money on therapy that may not be valid,” says Michael Chez, a pediatric neurologist and lead investigator of the study at Sutter.
A major difference between the Sutter trial and those in China is that his will use the child’s own stem cells, rather than those from a donor. Chez hypothesizes that one way autologous stem cell infusion might work is by reducing inflammation within the body’s immune system. This would answer previous research that suggests that autism may be an autoimmune disease. “One of our exploratory goals will be to look at inflammatory markers in cells,” he says.
The study’s primary goal, however, will be assessing changes in patients’ speaking and understanding of vocabulary. For each individual, researchers will create a baseline benchmark that establishes current skill levels. The group will be evenly divided, with one initially receiving an infusion of their own, unmodified cord blood stem cells and the other a placebo treatment of saline injection. Six months later, all of the children will be tested on their ability to comprehend and form words. The groups will then be switched. In the course of the 13-month-long study, both groups will receive only one stem cell therapy infusion.
Not all stem cell scientists who study neurodevelopmental diseases are ready to invest great hope that the autism stem cell trial will succeed. “I wish I could tell you I’m optimistic about the end results,” says James Carroll, a pediatric neurologist at the Georgia Health Sciences University in Augusta who began a clinical trial two years ago to better understand how stem cell therapy affects patients with cerebral palsy. “But so far we have not seen any kind of miraculous recovery in our cerebral palsy patients. I would be delighted if that changes.”
Members in the stem cell therapy patient community think Chez will have no shortage of volunteers for the trial. Jeremy Lowey, who lives in Sacramento and has struggled with a rare condition known as non-verbal learning disorder, arranged for his own stem cell therapy treatment in India last year, which he called life-changing. He receives numerous Facebook requests from parents of autistic children who are curious to know more. He always begins his conversations by saying, “Go slowly and think hard about your decision.”
Source: Scientific American
Patient Suffers Severe Amnesia but Musical Memory Remains Intact
ScienceDaily (Aug. 21, 2012) — Together with his team, Prof. Christoph Ploner, director of the Department of Neurology at the Virchow campus, examined a professional cellist who suffered from encephalitis caused by a herpes virus. As a result of the inflammation, the patient developed serious disturbances in memory.
Both his memory for the past (retrograde amnesia), as well as the acquisition of new information (anterograde amnesia) were affected. Whereas the patient was unable to recount any events from his private or professional life, or remember any of his friends or relatives, he retained a completely intact musical memory. Furthermore, he was still able to sight-read and play the cello.
For the systematic examination of his musical memory, Dr. Carsten Finke, Nazli Esfahani and Prof. Christoph Ploner developed various tests that take the beginning of his amnesia into account. In comparison to amateur musicians and professional musicians from the Berlin Philharmonic, the patient showed a normal musical memory in all tests. He not only remembered music pieces from the past, but was also able to retain music he had never heard before.
"The findings show that musical memory is organized at least partially independent of the hippocampus, a brain structure that is central to memory formation," says Carsten Finke, the primary author of the study. "It is possible that the enormous significance of music throughout all times and in all cultures contributed to the development of an independent memory for music."
Carsten Finke and his colleagues hope that the intact musical memory in patients with amnesia can be used to stimulate other memory content. In this way, perhaps a particular melody can be connected to a person or an everyday task, for example taking medicine.
Source: Science Daily
MRI Findings Shed Light On Multiple Sclerosis
ScienceDaily (Aug. 21, 2012) — New magnetic resonance imaging (MRI) research shows that changes in brain blood flow associated with vein abnormalities are not specific for multiple sclerosis (MS) and do not contribute to its severity, despite what some researchers have speculated. Results of the research are published online in the journal Radiology.
"MRI allowed an accurate evaluation of cerebral blood flow that was crucial for our results," said Simone Marziali, M.D., from the Department of Diagnostic Imaging at the University of Rome Tor Vergata in Rome.
MS is a disease of the central nervous system in which the body’s immune system attacks the nerves. There are different types of MS, and symptoms and severity vary widely. Recent reports suggest a highly significant association between MS and chronic cerebrospinal venous insufficiency (CCSVI), a condition characterized by compromised blood flow in the veins that drain blood from the brain. This strong correlation has generated substantial attention from the scientific community and the media in recent years, raising the possibility that MS can be treated with endovascular procedures like stent placement. However, the role of brain blood flow alterations on MS patients is still unclear.
To investigate this further, Italian researchers compared brain blood flow in 39 MS patients and 26 healthy control participants. Twenty-five of the MS patients and 14 of the healthy controls were positive for CCSVI, based on Color-Doppler-Ultrasound (CDU) findings. The researchers used dynamic susceptibility contrast-enhanced (DSC) MRI to assess blood flow in the brains of the study groups. DSC MR imaging offers more accurate assessment of brain blood flow than that of CDU. MRI and CDU were used to assess two different anatomical structures.
While CCSVI-positive patients showed decreased cerebral blood flow and volume compared with their CCSVI-negative counterparts, there was no significant interaction between MS and CCSVI for any of the blood flow parameters. Furthermore, the researchers did not find any correlation between the cerebral blood flow and volume in the brain’s white matter and the severity of disability in MS patients.
The results suggest that CCSVI is not a pathological condition correlated with MS, according to Dr. Marziali, but probably just an epiphenomenon — an accessory process occurring in the course of a disease that is not necessarily related to the disease. This determination is important because, to date, studies of the prevalence of CCSVI in MS patients have provided inconclusive results.
"This study clearly demonstrates the important role of MRI in defining and understanding the causes of MS," Dr. Marziali said. "I believe that, in the future, it will be necessary to use powerful and advanced diagnostic tools to obtain a better understanding of this and other diseases still under study."
Source: Science Daily
Bipolar disorder and creativity found to be linked
Does some fine madness yield great artists, writers, and scientists? The evidence is growing for a significant link between bipolar disorder and creative temperament and achievement.
People with bipolar disorder swing repeatedly from depression to euphoria and hyperactivity, or intensely irritable mood states. Sometimes likened to being on an emotional rollercoaster, each swing up then down affects one’s behaviour, energy levels, thought patterns and sleep.
Also known as manic-depressive illness, bipolar disorder is strongly genetically linked, passing down through each generation of an affected family. It is fairly common and very treatable with modern medicines and psychotherapy.
(Source: machineslikeus.com)
Can’t sleep? You could have inherited the insomnia gene
21 August 2012 by Lois Rogers
Thousands of otherwise healthy people put up with a level of sleep deprivation that would drive the rest of us insane. But they are not the usual candidates for insomnia, such as shift workers or those with severe mental illness. Instead, they belong to a newly identified group of people born without the ‘comfort’ genes needed for easy sleep.
This means they are immune to the feeling of warmth and relaxation which sends an average person off to sleep within 15 minutes. Their genes are designed instead to maintain a state of mental alertness. This makes normal, prolonged sleep impossible so they sleep fitfully, in only short bursts. Even then, their lack of ‘comfort’ genes may mean they struggle to get comfortable, fussing about the bedding or finding their sleeping position.
There are other so-called insomnia genes — some cause repeated periods of wakefulness in the small hours of the night or at the slightest disturbance, or drive an affected person to leap out of bed raring to start the day at 4am, but leave them exhausted by 4pm. Until recently, insomnia was considered a purely psychological complaint triggered by stress, grief, or sleep disruption as a result of shift work or jet lag.
But doctors are now unravelling the genetic explanation of why at least one-third of us have intermittent or constant sleep problems. Even so, it’s already thought there could be six or more different types of insomnia linked to genes. This means it will be possible to develop drugs to block the effect of the chemical signals they produce.
(Source: Daily Mail)