Posts tagged brain
Articles and news from the latest research reports.
New Study Reveals How Humans Became Right-Handed
According to a new study led by Dr Gillian Forrester of the University of Sussex, a predominance to be right-handed is not a uniquely human trait but one shared by great apes.
The study, published in the journal Behavioural Brain Research, analyzed hand actions directed towards either objects or individuals in chimpanzees, gorillas and children, and found that all three species are right-handed for actions to objects, but not for actions directed to individuals.
The results support a theory that human right-handedness is a trait developed through tool use that was inherited from an ancestor common to both humans and great apes. The findings challenge a widely held view that right-handed dominance in humans was a species-unique trait linked to the emergence of language.
“Humans have been tool users for 2.5 million years, while the current view is that language only emerged one hundred thousand years ago,” Dr Forrester said. “Our findings provide the first non-invasive results from naturalistic behavior, suggesting that language emerged as a consequence of left hemisphere brain regions that were already evolved to process regular sequences of actions. The structure found in language may have developed from pre-existing brain processes adapted from experience with tool-use.”
Let there be sight: Burst of neural activity necessary for vision
A sudden and mysterious burst of activity originating in the retina of a developing fetus spurs brain connections that are essential to development of finely-tuned sight, Yale researchers report in the journal Nature. Interference with this spontaneous wave of activity could play a role in neurodevelopmental disorders such as autism, the scientists speculate.
The study in mice is the first to demonstrate in a living animal that this wave of activity spreads throughout large regions of the brain and is crucial to wiring of the visual system. Without the wiring, infants would not be able to distinguish details in their environment.
“If you interfere with this activity, the circuits are all messed up, the wiring details are all wrong,” said Michael Crair, the William Ziegler III Professor of Neurobiology and Professor of Ophthalmology and Visual Science and senior author of the study.
For instance, this activity might allow a newborn human baby to perceive such details as the five fingers attached to her hand or her mother’s face. This wave wires up the visual system so that infants are poised to learn from their environment soon after birth.
The development of animals from a fertilized egg into trillions of intricately connected and specialized cells is the result of a precisely timed expression of genes. However, the Nature paper introduces another necessary factor — a mysterious wave of activity arising in the retina itself that propagates through several regions of the brain. Crair terms this wave an emergent property, or a trait possessed by a complex system that cannot be directly traced to its individual parts. This experiment in living, neonatal mice shows that this wave is crucial to the proper wiring not only of the visual system but other brain areas as well.
Crair said his lab plans to explore whether interruptions of this activity might play a role in neurodevelopmental disorders such as autism or schizophrenia.
(Source: news.yale.edu)
Study links eating chocolate to winning Nobels
Take this with a grain of salt, or perhaps some almonds or hazelnuts: A study ties chocolate consumption to the number of Nobel Prize winners a country has and suggests it’s a sign that the sweet treat can boost brain power.
No, this does not appear in the satirical Onion newspaper. It’s in the prestigious New England Journal of Medicine, which published it online Wednesday as a “note” rather than a rigorous, peer-reviewed study.
The author — Dr. Franz Messerli, of St. Luke’s-Roosevelt Hospital and Columbia University in New York — writes that there is evidence that flavanols in green tea, red wine and chocolate can help “in slowing down or even reversing” age-related mental decline — a contention some medical experts may dispute.
Nevertheless, he examined whether a country’s per-capita chocolate consumption was related to the number of Nobels it had won — a possible sign of a nation’s “cognitive function.” Using data from some major chocolate producers on sales in 23 countries, he found “a surprisingly powerful correlation.”
Is the afterlife full of fluffy clouds and angels?
What does the neuroscientist Colin Blakemore make of an American neurosurgeon’s account of the afterlife?
Have you ever noticed that more people come back from Heaven than from Hell? We have all read those astonishing reports of near-death experiences (NDEs, as the aficionados call them) – the things that people say have happened to them when they almost, but don’t quite, shuffle off the coil.
They are nearly always pleasant and deeply reassuring in a saccharin-soaked way. Lots of spinning down warm, dark tunnels to the sound of celestial music; lots of trips along country lanes lined with hedges, towards the light of a welcoming cottage at the end of the road; lots of tumbling down Alice-in-Wonderland rabbit holes, but without the damaging effects of gravity.
True, Dr Maurice S Rawlings Jr, MD, heart surgeon in Chattanooga, Tennessee, and author of To Hell and Back, did have patients who reported very nasty NDEs after they came back on his operating table. Booming noises; licking flames and all that Mephistophelian stuff. But perhaps that tells us more about the challenges of living in Chattanooga, Tennessee, than about the metaphysics of life after death.
Predictably, the amazingly consistent, remarkably heaven-like experiences recounted by the majority of NDE-ers (yes, that really is what the experts call them) have been summarily dismissed by materialist sceptics – like me. Of course the brain does funny things when it’s running out of oxygen. The odd perceptions are just the consequences of confused activity in the temporal lobes.
But NDEs have taken on a new cloak of respectability with a book by a Harvard doctor. Proof of Heaven, by Eben Alexander, will make your toes wiggle or curl, depending on your prejudices. What’s special about his account of being dead is that he’s a neurosurgeon. At least that’s what the publicity is telling us. It’s a cover story in Newsweek magazine, with a screaming headline: “Heaven is Real: a doctor’s account of the afterlife”.
Cognitive reorganization during pregnancy and the postpartum period: An evolutionary perspective
Where the non-human animal research investigating reproduction-induced cognitive reorganization has focused on neural plasticity and adaptive advantage in response to the demands associated with pregnancy and parenting, human studies have primarily concentrated on pregnancy-induced memory decline. The current review updates Henry and Rendell’s 2007 meta-analysis, and examines cognitive reorganization as the result of reproductive experience from an adaptationist perspective. Investigations of pregnancy-induced cognitive change in human females may benefit by focusing on areas, such as social cognition, where a cognitive advantage would serve a protective function, and by extending the study duration beyond pregnancy into the postpartum period.
(Source: epjournal.net)
NIH researchers provide detailed view of brain protein structure
Results may help improve drugs for neurological disorders
Researchers have published the first highly detailed description of how neurotensin, a neuropeptide hormone which modulates nerve cell activity in the brain, interacts with its receptor. Their results suggest that neuropeptide hormones use a novel binding mechanism to activate a class of receptors called G-protein coupled receptors (GPCRs).
“The knowledge of how the peptide binds to its receptor should help scientists design better drugs,” said Dr. Reinhard Grisshammer, a scientist at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and an author of the study published in Nature.
Binding of neurotensin initiates a series of reactions in nerve cells. Previous studies have shown that neurotensin may be involved in Parkinson’s disease, schizophrenia, temperature regulation, pain, and cancer cell growth.
Dr. Grisshammer and his colleagues used X-ray crystallography to show what the receptor looks like in atomic detail when it is bound to neurotensin. Their results provide the most direct and detailed views describing this interaction which may change the way scientists develop drugs targeting similar neuropeptide receptors.
X-ray crystallography is a technique in which scientists shoot X-rays at crystallized molecules to determine a molecule’s shape and structure. The X-rays change directions, or diffract, as they pass through the crystals before hitting a detector where they form a pattern that is used to calculate the atomic structure of the molecule. These structures guide the way scientists think about how proteins work.
Neurotensin receptors and other GPCRs belong to a large class of membrane proteins which are activated by a variety of molecules, called ligands. Previous X-ray crystallography studies showed that smaller ligands, such as adrenaline and retinal, bind in the middle of their respective GPCRs and well below the receptor’s surface. In contrast, Dr. Grisshammer’s group found that neurotensin binds to the outer part of its receptor, just at the receptor surface. These results suggest that neuropeptides activate GPCRs in a different way compared to the smaller ligands.
Forming well-diffracting neuropeptide-bound GPCR crystals is very difficult. Dr. Grisshammer and his colleagues spent many years obtaining the results on the neurotensin receptor. During that time Dr. Grisshammer started collaborating with a group led by Dr. Christopher Tate, Ph.D. at the MRC Laboratory of Molecular Biology, Cambridge, England. Dr. Tate’s lab used recombinant gene technology to create a stable version of the neurotensin receptor which tightly binds neurotensin. Meanwhile Dr. Grisshammer’s lab employed the latest methods to crystallize the receptor bound to a short version of neurotensin.
The results published today are the first X-ray crystallography studies showing how a neuropeptide agonist binds to neuropeptide GPCRs. Nonetheless, more work is needed to fully understand the detailed signaling mechanism of this GPCR, said Dr. Grisshammer.
(Source: ninds.nih.gov)
A wireless low-power, high-quality EEG headset
Imec, Holst Centre and Panasonic have developed a new prototype of a wireless EEG (electroencephalogram, or brain waves) headset designed to be a reliable, high-quality and wearable EEG monitoring system.
The system combines ease-of-use with ultra-low power electronics. Continuous impedance monitoring and the use of active electrodes increases the quality of EEG signal recording compared to former versions of the system.
The EEG data is transmitted to a receiver located up to 10 meters away. The headset integrates active electrodes (reduce the susceptibility of the system to power-line interference and cable motion artifacts to improve signal quality), EEG amplifier, microcontroller, and low-power wireless transmitter.
The receiver can continuously record 8-channel EEG signals while concurrently recording electrode-tissue contact impedance (ETI), a measure of contact quality.
The system has a high (>92 dB) common-mode rejection ratio (to reduce interference from power lines and other sources) and low noise (<6 µVpp, 0.5-100Hz), with configurable cut-off frequency (to filter out high or low frequencies).
The heart of the system is the low-power (750µW) 8-channel EEG monitoring chipset. Each EEG channel consists of two active electrodes and a low-power analog signal processor. The EEG channels are designed to extract high-quality EEG signals under a large amount of common-mode interference. The active electrode chips have buffer functionality with high input impedance (1.4GΩ at 10Hz), enabling recordings from dry electrodes, and low output impedance reducing the power-line interference without using shielded wires
The system is integrated into imec’s EEG headset with dry electrodes, which enables EEG recordings with minimal set-up time. The small size of the electronics system, measuring only 35mm x 30mm x 5mm (excluding battery), allows easy integration in any other product.
Human neural stem cells study offers new hope for children with fatal brain diseases
New findings demonstrate potential to treat a wide variety of disorders that affect myelin
Physician-scientists at Oregon Health & Science University Doernbecher Children’s Hospital have demonstrated for the first time that banked human neural stem cells — HuCNS-SCs, a proprietary product of StemCells Inc. — can survive and make functional myelin in mice with severe symptoms of myelin loss. Myelin is the critical fatty insulation, or sheath, surrounding new nerve fibers and is essential for normal brain function.
This is a very important finding in terms of advancing stem cell therapy to patients, the investigators report, because in most cases, patients are not diagnosed with a myelin disease until they begin to show symptoms. The research is published online in the journal Science Translational Medicine.
Myelin disorders are a common, extremely disabling, often fatal type of brain disease found in children and adults. They include cerebral palsy in children born prematurely as well as multiple sclerosis, among others.
Using advanced MRI technology, researchers at OHSU Doernbecher Children’s Hospital also recently recognized the importance of healthy brain white matter at all stages of life and showed that a major part of memory decline in aging occurs due to widespread changes in the white matter, which results in damaged myelin and progressive senility (Annals of Neurology, September 2011).
Stony Brook Researchers Develop Neuroimaging Technique Capturing Cocaine’s Devastating Effect on Brain Blood Flow
Researchers from the Department of Biomedical Engineering at Stony Brook University have developed a high-resolution, 3D optical Doppler imaging tomography technique that captures the effects of cocaine restricting the blood supply in vessels – including small capillaries – of the brain. The study, reported in Molecular Psychiatry, and with images on the journal’s October 2012 cover, illustrates the first use of the novel neuroimaging technique and provides evidence of cocaine-induced cerebral microischemia, which can cause stroke.
In “Cocaine-induced cortical microischemia in the rodent brain: clinical implications,” the researchers discovered that cocaine administered in doses equivalent to those normally taken by abusers caused constriction in blood vessels that inhibited CBF for varying lengths of time. Brain arteries, veins, and even capillaries, the smallest vessels, were affected by the doses. CBF was markedly decreased within just two-to-three minutes after drug administration. In some vessels, a decrease in CBF reached 70 percent. Recovery time for the vessels varied. Cocaine interrupted CBF in some arteriolar branches for more than 45 minutes. This effect became more pronounced after repeated cocaine administration.
“Our study revealed evidence of cocaine-induced cerebral microischemic changes in multiple experimental models, and we were able to clearly image the process and vasoactive effects at a microvascular level,” said study Principal Investigator Yingtian Pan, PhD, Professor, Department of Biomedical Engineering, Stony Brook University. “These clinical changes jeopardize oxygen delivery to cerebral tissue making it vulnerable to ischemia and neuronal death.”
Cambrian fossil pushes back evolution of complex brains
The remarkably well-preserved fossil of an extinct arthropod shows that anatomically complex brains evolved earlier than previously thought and have changed little over the course of evolution. According to University of Arizona neurobiologist Nicholas Strausfeld, who co-authored the study describing the specimen, the fossil is the earliest known to show a brain.
The discovery will be published in the Oct. 11 issue of the journal Nature.
Embedded in mudstones deposited during the Cambrian period 520 million years ago in what today is the Yunnan Province in China, the approximately 3-inch-long fossil, which belongs to the species Fuxianhuia protensa, represents an extinct lineage of arthropods combining an advanced brain anatomy with a primitive body plan.
The fossil provides a “missing link” that sheds light on the evolutionary history of arthropods, the taxonomic group that comprises crustaceans, arachnids and insects.
The researchers call their find “a transformative discovery” that could resolve a long-standing debate about how and when complex brains evolved.
"No one expected such an advanced brain would have evolved so early in the history of multicellular animals," said Strausfeld, a Regents Professor in the UA department of neuroscience.
According to Strausfeld, paleontologists and evolutionary biologists have yet to agree on exactly how arthropods evolved, especially on what the common ancestor looked like that gave rise to insects.
"There has been a very long debate about the origin of insects," Strausfeld said, adding that until now, scientists have favored one of two scenarios.
Some believe that insects evolved from an ancestor that gave rise to the malacostracans, a group of crustaceans that include crabs and shrimp, while others point to a lineage of less commonly known crustaceans called branchiopods, which include, for example, brine shrimp.
Because the brain anatomy of branchiopods is much simpler than that of malacostracans, they have been regarded as the more likely ancestors of the arthropod lineage that would give rise to insects.
(Source: eurekalert.org)