neurophilosophy | October 14, 2008When 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 deprived…
neurophilosophy | October 13, 2008
Japanese researchers have developed a design concept for a light microscope which could in principle be used for imaging of nanoscale objects. The device would rely on a novel subwavelength imaging technique which allows for the visualization of objects that are smaller than the wavelength of the photons used in the device.
Once thought to be impossible, subwavelength imaging can now be performed because of the development of nanostructured metamaterials with a negative refractive index, which can act as a lens by focusing incident light. Until now though, such materials only worked at one…
neurophilosophy | October 12, 2008The BBC has film footage of the legendary Bluegrass musician Eddie Adcock playing the banjo whilst having his brain operated on.
Adcock is suffering from essential tremor, a progressive neurological condition characterised by tremors in the arms which appear during voluntary movements and which are thought to occur as a result of degeneration of cerebellar Purkinje cells.
The film shows neurosurgeons at Vanderbilt University Medical Center in Nashville, Tennessee treating Adcock with deep brain stimulation (DBS), in which electrodes are implanted into the thalamus. Together with the…
neurophilosophy | October 10, 2008This reconstruction, produced by researchers from the European Molecular Biology Laboratory in Heidelberg, Germany using a technique called digital scanned laser light sheet fluorescence microscopy, shows the movements of all 16,000 cells in an 18-hour-old zebrafish embryo.
To make the film, the researchers injected a fluorescent protein into an embryo at the one cell stage. They began imaging at the 64-cell stage and recorded 370 images, each less than 3 thousandths of a millimeter apart, in multiple directions at 1,226 time points separated by 90 second intervals. The recording was…
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…
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 | October 1, 2008These X-rays show a knife plunged into the skull of a 16-year-old boy from southeast London. Fortunately, his injuries were nowhere near as serious as they might have been - according to a police officer quoted in The Times, "the blade was a kitchen knife and because of that it was flexible and went around the bone." He has, however, started walking with a limp, and his reaction times have slowed.
Related:
Unusual penetrating brain injuries
The incredible case of Phineas Gage
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 29, 2008This scanning electron micrograph of diatoms attached to an invertebrate host won first place in the photography category of the 2008 Science & Engineering Visualization Challenge.
Other winners and honorable mentions can be seen in this slideshow.
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…
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, 2008A 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, 2008The 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…
neurophilosophy | September 22, 2008The current issue of The Economist contains a short article about how weblogs are beginning to change the way science is being communicate:
Earlier this month Seed Media Group...launched the latest version of Research Blogging, a website which acts as a hub for scientists to discuss peer-reviewed science...The new portal provides users with tools to label blog posts about particular pieces of research, which are then aggregated, indexed and made available online.
...According to Adam Bly, Seed's founder, internet-aided interdisciplinarity and globalisation, coupled with a generational…
neurophilosophy | September 17, 2008The 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, 2008Welcome 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 goes…
neurophilosophy | September 14, 2008I took this photograph yesterday at a park in central London. My knowledge of botany is scant, so I have no idea what species it is.
neurophilosophy | September 14, 2008The Seed Media Group is offering a big prize to celebrate the millionth comment on the ScienceBlogs network. One lucky reader, selected at random from those who comment over the next few days, will win a four day trip to New York City, which includes four nights in a 4-star hotel and dinner with their favourite ScienceBlogger, who will also be flown in for the occasion.
Many of the bloggers on the network are also holding parties across the States and elsewhere in the world. Here in the U.K., Nick Anthis, Kara Contreary, Selvakumar Ganesan Ed Yong and I have planned a little get-together on…