neuroscience
neurophilosophy | October 14, 2008
When David Savage was 19 years old, his right hand was crushed in a metal-stamping machine and subsequently amputated at the wrist by doctors. Afterwards, Savage was fitted with a mechanical cable-hook prosthesis, which he wore until December, 2006, when he became the third American recipient of a hand transplant from a cadaver donor (above).
Amputation of a limb leads to significant reorganization of the primary somatosensory cortex, that part of the brain which processes touch- and pain-related information. The cortical region normally devoted to the amputated body part is suddenly…
edyong | October 12, 2008
It's mid-October. For most of us, our New Year's resolutions have long been forgotten and our bad habits remain frustratingly habitual. The things that are bad for us often feel strongly compelling, be they high-fat foods, gambling or alcohol. And nowhere is the problem of addiction more widespread, serious and dangerous than the case of cigarette smoking.
Smoking is the leading preventable cause of death in the developed world, and in the UK, it kills five times more people than all non-medical causes combined. The dangers of smokers are both well-established and well-known, and…
neurophilosophy | October 8, 2008In his 1941 book Man on His Nature, the Nobel Prize-winning physiologist Sir Charles Sherrington described the brain as "an enchanted loom where millions of flashing shuttles weave a dissolving pattern." Little could he have known that within 50 years neuroscientists would have at their disposal techniques for visualizing this pattern.
These techniques are collectively known as calcium imaging. Developed in the 1980s, they use synthetic chemical dyes or genetic constructs whose spectral properties change when they bind calcium ions, leading to a change in fluoresence which can be detected…
neurophilosophy | October 7, 2008The transmissible spongiform encephalopathies (TSEs), which include variant Creutzfeldt-Jakob Disease in humans, "Mad Cow" Disease in cattle and scrapie in sheep, are progressive and fatal neurodegenerative disorders characterized by the accumulation within nerve cells of an abnormally folded and insoluble form of the prion protein.
The infectious agent which causes these diseases is generally believed to be the prion protein itself. According to Stanley Prusiner's prion hypothesis, abnormal prion molecules act as a "seed" upon their entry into a cell, causing the normal cellular form of the…
edyong | October 2, 2008
You are not the person you used to be. Two weeks ago, the surface of your skin was covered with a completely different set of cells, which have since died and flaked off. Four month ago, you had a wholly different set of red blood cells. Since birth, your body has grown tremendously in size and much of it is constantly regenerating, replacing old cells with new ones.
But your brain is different. At birth, the part of your brain that controls your most human abilities - the neocortex - came fully equipped with 100 billion neurons. These same neurons have lasted throughout the years and…
neurophilosophy | October 1, 2008
Cataract 3, Bridget Riley, 1967.
In the 1960s, the British artist Bridget Riley began to develop a distinctive style characterised by simple and repetitive geometric patterns which create vivid illusions of movement and sometimes colour and often have a disorientating effect usually described by observers as "shimmering" or "flickering". With her explorations of the dynamic nature of optical phenomena, Riley became one of the most prominent exponents of what came to be known as Op Art.
Many optical illusions are generated by the brain, and studying them has provided us with a better…
neurophilosophy | September 29, 2008Learning to play a musical instrument is known to involve both structural and functional changes in the brain. Studies published in recent years have established, for example, that professional keyboard players have increased gray matter volume in motor, auditory and visual parts of the brain, and that violinists have a larger somatosensory cortical representation of the left hand than do non-musicians.
Musical training is a complex process involving simultaneously perceiving the inputs from the senses of hearing, sight and touch, as well as co-ordinating these with the outputs of the motor…
neurophilosophy | September 26, 2008Around 15 years ago, researchers discovered that the adult rodent brain contains discrete populations of stem cells which continue to divide and produce new neurons throughout life. This discovery was an important one, as it overturned a persistent dogma in neuroscience which held that the adult mammalian brain cannot regenerate.
Since then, neural stem cells have been the subject of intensive investigation, in large part because of their potential uses in treating neurological conditions such as Parkinson's Disease, stroke and epilepsy. Even so, the function of newly-generated neurons has…
edyong | September 25, 2008The art of auctioning is an ancient one. The concept of competitively bidding for goods has lasted from Roman times, when spoils of war were divvied up around a planted spear, to the 21st century, when the spoils of the loft are sold through eBay. But despite society's familiarity with the concept, people who take part in auctions still behave in a strange way - they tend to overbid, offering more money than what they actually think an object is worth.
Some economists have suggested that people overbid because they are averse to risk. They would rather make spend more money to be sure of a…
neurophilosophy | September 25, 2008Radiation therapy is a common treatment for adults and children who present with tumours in or close to the brain. In the last 20 years, advances in radiotherapy have significantly improved the prognosis for brain cancer patients. However, the resulting longer survival rates reveal that the therapy has deleterious effects on brain health - even at low doses, radiation leads to cognitive impairments in later life.
These impairments, which include attention deficits and learning disabilities, occur as a result of the effects of radiation on the hippocampus. This structure is known to be…
neurophilosophy | September 25, 2008
A short piece in the MIT Technology Review describes a new retinal implant designed to remain in place for long periods of time:
In retinal diseases such as acute macular degeneration and retinitis pigmentosa, the light-sensing cells of the retina may no longer work, even though the neurons that carry signals from these cells to the brain are still healthy. The Boston project uses an array of electrodes to stimulate these cells and reproduce a simplified visual image in the subject's brain. A camera mounted on a pair of eyeglasses captures an image, which is rapidly processed by a…
neurophilosophy | September 24, 2008
The September issue of Scientific American contains an excellent and lengthy article about a state-of-the-art technique called optogenetics, by molecular physiologist Gero Miesenböck, who has been instrumental in its development.
As its name suggests, optogenetics is a combination of optics and genetic engineering. It is a powerful new method for investigating the function of neuronal circuits, based a number of light-sensitive proteins which have recently been isolated from various micro-organisms.
By fusing their genes to promoters which control where they will be activated, researchers…
neurophilosophy | September 23, 2008We continually rely on our abilities of spatial navigation, be it for the daily commute to work, a trip to the local supermarket, or simply to make our way to the bathroom in the middle of the night. These tasks involve complex cognitive processes, yet most people perform them effortlessly and some develop them to a remarkable degree. Take, for example, London taxi drivers, who have a highly detailed knowledge of the 25,000 streets that lie within a six-mile radius of Charing Cross station, as well as the locations of thousands of "points", or landmarks, such as nightclubs, hospitals, hotels…
sporte | September 20, 2008Hey high school teachers! Are your students interested in the brain?
Who isn't?
Three winners will win all-expense-paid trips to present their work in a poster session in Seattle at the 2009 Annual Meeting of the American Academy of Neurology. Their teachers get to come too! I can tell you, Seattle is a fun place to visit.
Low tide at Golden Gardens, July 2008
Plus, three student winners will get $1000 in cash in addition to the trip.
Find out more at www.aan.com/achieve.
neurophilosophy | September 17, 2008
The new issue of Seed contains a short piece by me called Beauty and the Brain, about the emerging field of neuroaesthetics, which seeks to investigate the neural correlates of the appreciation of beauty in art.
Neuroaesthetics was pioneered by Semir Zeki, who has been criticized as making extravagant claims about what can be achieved by the scientific study of such subjective phenomena. The work may seem fanciful, but it could eventually have direct clinical applications: we know, for example, that depressed patients have a diminished appreciation of beauty, and a new study shows that…
neurophilosophy | September 15, 2008
Welcome to the 54th edition of Encephalon, the neuroscience and psychology blog carnival. This edition has everything from the perception of colour and shapes to behavioural economics, the neuroscience of sports and squabbling psychologists.
First up is the editor's choice: an in-depth review of the evolution of modularity in the brain by Caio Maximino. A brain module is a functionally and cytoarchitectonically distinct region of the brain. In his post, Caio begins with how the concept of modularity arose historically. He then explains how the developing neural tube becomes segmented and…
edyong | September 13, 2008
As you read this post, your computer is probably busy. You may have multiple programs running in the background, with email clients, anti-virus software or file-sharing software all competing for valuable memory. The ability of computers to multi-task has grown substantially in recent years, as processors have become increasingly powerful.
Evolution has chartered a similar course, and humans are particularly talented at dividing our attention among multiple priorities. Now scientists are showing that the asymmetrical differences between the two sides of our brain are essential for this…
neurophilosophy | September 11, 2008Hallucinations are often associated with psychiatric conditions such as schizophrenia or with LSD and related drugs. Hearing voices is a characteristic symptom which is reported by about 70% of schizophrenic patients, as well as by some 15% of patients with mood disorders such as depression; and those under the influence of LSD often experience extreme spatial distortions and surreal visions.
Most common are auditory and visual hallucinations, but the other senses can also produce mirages. Temporal lobe epilepsy or brain injury can lead to phantosmia, or olfactory hallucinations, during…
purepedantry | September 9, 2008Over at Economics of Contempt, there is an argument that liberal media bias has to exist because there is evidence that partisanship changes the way that our brains process information. (This is not his only evidence, but it is part of it.)
Now, I don't want to get into a discussion about the existence or nonexistence of a liberal (or conservative) media bias. What I take issue with is the particular study that Economics of Contempt cites as evidence of this bias. I think that he is misapplying the results of that study.
Economics of Contempt cites the results of Westen et al. 2006.…
neurophilosophy | September 3, 2008In the Nature Neuroscience podcast NeuroPod, presenter Kerri Smith talks to authors of new papers from that journal about their research. The August 2008 episode (which is embedded below) includes discussions about the development of the concept of fairness in children and the effects of how imprinting of maternal and paternal genes affects development of the brain. There's also more about how magic can inform neuroscience.