brain
neurophilosophy | November 13, 2009IMAGINE sitting in a noisy restaurant, across the table from a friend, having a conversation as you eat your meal. To communicate effectively in this situation, you have to extract the relevant information from the noise in the background, as well as from other voices. To do so, your brain somehow "tags" the predictable, repeating elements of the target signal, such as the pitch of your friend's voice, and segregates them from other signals in the surroundings, which fluctuate randomly.
The ability to focus on your friend's voice while excluding other noises is commonly referred to as the…
edyong | November 12, 2009How would you fancy a holiday to Greece or Thailand? Would you like to buy an iPhone or a new pair of shoes? Would you be keen to accept that enticing job offer? Our lives are riddled with choices that force us to imagine our future state of mind. The decisions we make hinge upon this act of time travel and a new study suggests that our mental simulations of our future happiness are strongly affected by the chemical dopamine.
Dopamine is a neurotransmitter, a chemical that carries signals within the brain. Among its many duties is a crucial role in signalling the feelings of enjoyment we…
neurophilosophy | November 6, 2009A novel temporal illusion, in which the cause of an event is perceived to occur after the event itself, provides some insight into the brain mechanisms underlying conscious perception. The illusion, described in the journal Current Biology by a team of researchers from France, suggests that the unconscious representation of a visual object is processed for around one tenth of a second before it enters conscious awareness.
Chien-Te Wu and his colleagues at the Brain and Cognition Research Centre in Toulouse used a visual phenomenon called motion-induced blindness, in which a constantly…
neurophilosophy | October 28, 2009FOLLOWING the surgical removal of a body part, amputees often report sensations which seem to originate from the missing limb. This is thought to occur because the brain's model of the body (referred to as the body image) still contains a representation of the limb, and this leads to the experience that the missing limb is still attached to their body. Occasionally, amputees say that they cannot move their phantom limbs - they are perceived to be frozen in space, apparently because they cannot be seen.
Yet, research shows that the body image is malleable and easily manipulated. And according…
neurophilosophy | October 21, 2009
THE latest issue of Technology Review contains a photo essay by yours truly, called Time Travel Through the Brain, in which I look at how techniques used to investigate the brain have evolved during the 100 year history of modern neuroscience. The essay begins with a drawing by the great Spanish neuroanatomist Santiago Ramón y Cajal, who used the staining method discovered by Camillo Golgi to establish that nervous tissue is composed of cells, then goes on to describe more recent methods such as fibre tracing, Brainbow and various types of microscopy.
This image from the piece graced the…
neurophilosophy | October 18, 2009
USING an inventive new method in which mice run through a virtual reality environment based on the video game Quake, researchers from Princeton University have made the first direct measurements of the cellular activity associated with spatial navigation. The method will allow for investigations of the neural circuitry underlying navigation, and should lead to a better understanding of how spatial information is encoded at the cellular level.
In mice, spatial navigation involves at least four different cell types located in the hippocampus and surrounding regions. Place cells increase…
neurophilosophy | October 16, 2009THINKING of and saying a word is something that most of us do effortlessly many times a day. This involves a number of steps - we must select the appropriate word, decide on the proper tense, and also pronounce it correctly. The neural computations underlying these tasks are highly complex, and whether the brain performs them all at the same time, or one after the other, has been a subject of debate.
This debate has now apparently been settled, by a team of American researchers who had the rare opportunity to investigate language processing in conscious epileptic patients undergoing surgery…
edyong | October 15, 2009The placebo effect - the phenomenon where fake medicines sometimes work if a patient believes that they should - is a boon to quacks the world over. Why it happens is still a medical mystery but thanks to a new study, we have confirmation that the spine is involved.
Frank Eippert from the University Medical Center Hamburg-Eppendorf used a technique caled functional magnetic resonance imaging (fMRI) to scan the backbones of volunteers as they experienced the placebo effect. Eippert heated the recruits' forearms to the point of pain and he gave them cream to soothe the sting. The creams were…
edyong | October 14, 2009In the 1990s, Colombia reintegrated five left-wing guerrilla groups back into mainstream society after decades of conflict. Education was a big priority - many of the guerrillas had spent their entire lives fighting and were more familiar with the grasp of a gun than a pencil. Reintegration offered them the chance to learn to read and write for the first time in their lives, but it also offered Manuel Carreiras a chance to study what happens in the human brain as we become literate.
Of course, millions of people - children - learn to read every year but this new skill arrives in the context…
neurophilosophy | October 7, 2009VISION is now well known to modulate the senses of touch and pain. Various studies have shown that looking at oneself being touched can enhance tactile acuity, so that one can discriminate between two pinpoints which would otherwise feel like a single sensation. And last year, researchers from the University of Oxford showed that using binoculars to make a limb look larger or smaller than it actually is can respectively enhance and diminish painful sensations.
These phenomena occur because the brain fuses stimuli from different sensory systems to generate a coherent experience of bodily…
edyong | October 1, 2009This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science. The blog is on holiday until the start of October, when I'll return with fresh material.
At Harvard University, a group of creative scientists have turned the brains of mice into beautiful tangles of colour. By mixing together a palette of fluorescent proteins, they have painted individual neurons with up to 90 different colours. Their technique, dubbed 'Brainbow', gives them an unprecedented vision of how the brain's cells are connected to each other.
The art of looking at neurons had much…
neurophilosophy | September 14, 2009
THIS short film clip shows two images of the same scene. Watch it carefully, and see if you can spot the subtle differences between them. As you watch, your eyes will dart back and forth across the images, so that you can perceive the most important features. And even though you might not be consciously aware of the differences, your brain will have picked up on them. This implicit form of remembering is referred to as relational memory; in this case, the brain is encoding the perceptual associations between items in the image. And recent studies have shown that relational memory…
edyong | September 3, 2009As sufferers of post-traumatic stress syndrome know all too well, frightening experiences can be strong, long-lasting and notoriously difficult to erase. Now, we're starting to understand why. Far from trying to purge these memories, the brain actively protects them by hiring a group of molecular bodyguards called CSPGs (or chondroitin sulphate proteoglycans in full).
By studying the brains of rats, Nadine Gogolla from Harvard University found that CSPGs - large chains of sugars and proteins - accumulate in the space around nerve cells and form defensive nets around a select few. Dissolve…
edyong | August 30, 2009We all have a personal bubble, an invisible zone of privacy around our bodies. When strangers cross this boundary, it makes us feel uncomfortable. But not all of us - Daniel Kennedy from the California Institute of Technology has been studying a woman known only as SM, who lacks any sense of personal space.
SM suffers from a rare genetic disorder called Urbach-Wiethe disease, that causes parts of the brain's temporal lobes to harden and waste away. This brain damage has completely destroyed SM's amygdalae, a pair of small, almond-shaped structures that help us to process emotions.
Kennedy…
grrlscientist | August 26, 2009tags: Helen Keller, Anne Sullivan, newsreel footage, human behavior, learning, streaming video
Helen Keller, the American author, political activist and lecturer, and her instructor and lifelong companion, Anne Sullivan, appear in this Vitaphone newsreel from 1930. In this rare footage, Sullivan demonstrates how Helen Keller learned to talk. The final line of this footage, "I Am Not DUMB now!" is touching.
neurophilosophy | August 26, 2009
THIS weird and wonderful creature is the star-nosed mole (Condylura cristata), a small, semi-aquatic mammal which inhabits the low wetlands of eastern North America. Like other moles, it ekes out an existence in a network of narrow underground tunnels, and digs shallow surface tunnels where it forages for insects, worms and molluscs. Living as it does in almost complete darkness, the star-nosed mole has poorly developed eyes, and is virtually blind. Instead, it relies heavily on its remarkable star-shaped nose. This organ enables the star-nosed mole to decide whether something is edible with…
neurophilosophy | August 11, 2009AS Seed's Featured Blogger of the week, I have written a short article about the Human Connectome Project, in response to a news story on the magazine's website, called Mapping the brain's highways, by Azeen Ghorayshi.
Several weeks ago, the National Institutes of Health announced the Human Connectome Project, an ambitious $30 million five-year initiative, which aims to map the connectivity of the human brain.
Is this feasible? In short, the answer is no. The idea that a complete connectivity map of the whole brain can be achieved within five years is unrealistic, and producing a…
edyong | August 10, 2009People infected with the bird flu virus - influenza A subtype H5N1 - go through the usual symptoms of fever, aching muscles and cough. The virus is so virulent that 60% of infected humans have died. But according to a study in mice, the infection could also take a more inconspicuous toll on the brain, causing the sorts of damage that could increase the risk of diseases like Parkinson's and Alzheimer's many years after the virus has been cleared.
The link between influenza and Parkinson's disease is hardly old but certainly controversial. Previous studies have found no traces of flu genetic…
grrlscientist | July 26, 2009tags: philosophy, thinking the improbable, middle world, atoms, atheism, physics, Richard Dawkins, streaming video
In this video, Biologist Richard Dawkins makes a case for "thinking the improbable" by looking at how the human frame of reference limits our understanding of the universe [22:42]
TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world's leading thinkers and doers are invited to give the talk of their lives in 18 minutes.
edyong | July 23, 2009From the scientists who brought you the infamous 'Halle Berry neuron' and the 'Jennifer Aniston neuron' come the 'Oprah Winfrey neuron' and the 'Saddam Hussein neuron'.
Four years ago, Rodrigo Quian Quiroga from Leicester University showed that single neurons in the brain react selectively to the faces of specific people, including celebrities like Halle Berry, Jennifer Aniston and Bill Clinton. Now, he's back, describing single neurons that respond selectively to the concept of Saddam Hussein or Oprah Winfrey. This time, Quiroga has found that these neurons work across different senses,…