neurophilosophy | July 16, 2009
THE daguerreotype on the right is believed to be the only known image of railroad worker Phineas Gage, who was enshrined in the history of neuroscience one day in September, 1848, when a large iron rod he was using to tamp gunpowder into a hole in a rock caused an explosion and was propelled through his brain.
The photograph, which shows Gage holding the tamping iron, has been in the possession of photograph collectors Jack and Beverley Wilgus of Massachusetts for 30 years. They had believed it was of a whaler with his harpoon, but someone suggested it might in fact be Gage after it was…
neurophilosophy | July 13, 2009SWEARING occurs in most cultures - people swear to let off steam, or to shock or insult others. It is also a common response to a painful experience. We've all done it: after stubbing our toe, or hitting our thumb with a hammer, we draw a sharp breath and mutter a swear word. Until now, though, whether swearing actually alters our perception of pain had not been investigated. But according to a new study due to be published next month in the journal NeuroReport, swearing increases pain tolerance, enabling us to withstand at least one form of pain for longer.
Some pain theorists regard our…
neurophilosophy | July 10, 2009IN the 1860s, the French physician Paul Broca treated two patients who had lost the ability to speak after suffering strokes. When they died, he examined their brains, and noticed that both had damage to the same region of the left frontal lobe. About a decade later, neuropsychiatrist Carl Wernicke described a stroke patient who was unable to understand written words or what was said to him, and later found in this patient's brain a lesion towards the back of the left temporal lobe.
Thus was established the classical neurological model, in which language is localized to two specific areas…
neurophilosophy | July 3, 2009THE human brain is a true marvel of nature. This jelly-like 1.5kg mass inside our skulls, containing hundreds of billions of cells which between them form something like a quadrillion connections, is responsible for our every action, emotion and thought.
How did this remarkable and extraordinarily complex structure evolve? This question poses a huge challenge to researchers; brain evolution surely involved thousands of discrete, incremental steps, which occurred in the mists of deep time across hundreds of millions of years, and which we are unlikely to ever fully understand.
Nevertheless,…
neurophilosophy | June 26, 2009
THE term 'hypnosis' was coined by the Scottish physician James Braid in his 1853 book Neurypnology. Braid defined hypnosis as "a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental and visual eye". He argued that it was a form of "nervous sleep", and tried to distinguish his theory from that of the mesmerists, who believed that the effects of hypnosis were mediated by a vital force, or animal magnetism.
Because of mesmerism, and its association with stage entertainment and charlatanry, hypnosis was regarded with skepticism for much of its…
neurophilosophy | June 15, 2009MEMORY, Blake wrote, enables us to "traverse times and spaces far remote". It constitutes mental time travel, with which we can recollect, in vivid detail, events that took place many years ago. We have known, for the best part of a century, that memory is reconstructive rather than reproductive. That is, recollection involves piecing together specific details of the event, and mixing these with our own biases and beliefs. While not being completely accurate, our memories are, in most cases, reliable enough.
It is because of the reconstructive nature of memory that we are able to travel…
neurophilosophy | June 8, 2009People who place an emphasis on positive things and are generally optimistic are sometimes said to "see the world through rose-tinted glasses". According to a new study by Canadian researchers, this is more than just an idiom. The study, which has just been published in the Journal of Neuroscience, provides the first direct evidence that the mood we are in affects the way we see things by modulating the activity of the visual cortex. Their findings show that putting on the proverbial rose-tinted glasses of a good mood is not so much about colour, but about the broadness of the view.
A number…
neurophilosophy | May 30, 2009
A beautiful and macabre combination of anatomy and portraiture by Spanish artist Fernando Vicente.
neurophilosophy | May 26, 2009What did you do on March 13th, 1985? People with hyperthymesia (which has been characterized only recently, and of which just a handful of cases have so far been reported) would likely provide a vivid account of what happened on that day. And if this particular date has personal significance for you - if, for example, it was your wedding day, or the birth date of one of your children - then you will probably remember it quite well. But for most of us, the answer to this question is likely to be "I don't know".
In the journal Cortex, researchers describe the case of a patient with severe…
neurophilosophy | May 18, 2009The ability to interpret other peoples' emotions is vital for social interactions. We recognize emotions in others by observing their body language and facial expressions. The voice also betrays one's emotional state: words spoken in anger have a different rhythm, stress and intonation than those uttered with a sense of joy or relief. But how the emotional content of a voice is encoded in the brain was unclear.
Now though, Swiss researchers report that they have decoded the neural activity in the voice-sensitive regions of the brain, and demonstrate that this activity can be analyzed to…
neurophilosophy | May 11, 2009Music can be thought of as a form of emotional communication, with which the performer conveys an emotional state to the listener. This "language" is remarkably powerful - it can evoke strong emotions, and make your heart race or send tingles down your spine. And it is universal - the emotional content of a piece of music can be understood by anyone, regardless of cultural background.
Are the emotions evoked by piece of music similar to, and can they influence, other emotional experiences? The answer to these questions is unclear. But a new study, which has just been published in…
neurophilosophy | May 4, 2009Human cultural traits such as language, dress, religion and values are generally said to be passed from one generation to the next by social learning. And in animal species which have language, the same is true; male song birds, for example, learn the songs with which they serenade potential mates from older male relatives.
A new study, published online in the journal Nature, shows that the songs of isolated zebra finches evolve over multiple generations to resemble those of birds in natural colonies. These findings show that song learning in birds is not purely the product of nurture, but…
neurophilosophy | April 13, 2009If you look at a waterfall for about 30 seconds, and then shift your gaze to a nearby stationary object, such as a rock or a tree, that object will seem to drift slowly upwards. This well known optical illusion demonstrates a phenomenon called the motion after-effect, which is thought to occur as a result of adaptation - the brain compensates for movement in one direction, causing us to momentarily perceive a stationary objects to be moving in the other.
Although illusory motion can also be induced in the sense of touch, the brain is thought to process visual and tactile motion separately.…
neurophilosophy | April 3, 2009The journey undertaken by newly generated neurons in the adult brain is like the cellular equivalent of the arduous upstream migration of salmon returning to the rivers in which they were hatched. Soon after they are born in the subventricular zone near the back of the brain, these cells migrate to the front-most tip of of the olfactory bulb. This is the furthest point from their birth place, and they traverse two-thirds of the length of the brain to get there.
The first leg of this epic journey - the departure of the newborn cells from the subventricular zone - involves some of the…
neurophilosophy | April 1, 2009It is now well established that the adult mammalian brain contains stem cells which continue to generate new neurons throughout life. This discovery, and subsequent research, has transformed the way we think about the brain. It is, for example, known that physical and mental exercise can stimulate the growth of new nerve cells in a part of the brain which shrinks in Alzheimer's and depression, and so it is believed that such activities can reduce the risk of both conditions.
Despite all this, little is known about the mechanisms by which neural stem cells are directed to generate neurons.…
neurophilosophy | March 27, 2009If someone told you that they wanted to have a perfectly good leg amputated, or that they have three arms, when they clearly do not, you would probably be inclined to think that they are mentally disturbed. Psychiatrists, too, considered such conditions to be psychological in origin. Voluntary amputation, for example, was regarded as a fetish, perhaps arising because an amputee's stump resembles a phallus, whereas imaginary extra limbs were likely to be dismissed as the products of delusions or hallucinations.
However, these bizarre conditions - named body integrity identity disorder (BIID)…
neurophilosophy | March 24, 2009Optogenetics is a newly developed technique based on a group of light-sensitive proteins called channelrhodopsins, which were isolated recently from various species of micro-organism. Although relatively new, this technique has already proven to be extremely powerful, because channelrhodopsins can be targeted to specific cells, so that their activity can be controlled by light, on a millisecond-by-millisecond timescale.
A group of researchers from Stanford University now report a new addition to the optogenetic toolkit, and demonstrate that it can be used to precisely control biochemical…
neurophilosophy | March 20, 2009The way we perceive other people has a big influence on how we interact with them. For example, attractive people are more likely to be perceived as talented than less attractive people, and this so-called "halo effect" is often reflected in our behaviour towards them. Similarly, we tend to favour people perceived to be like us over people who are perceived to be different ("in-group bias").
It turns out that the way we perceive others can also influence our own sense of touch. In a new study published in the open access journal PLoS One, researchers from the University of Bologna report that…
neurophilosophy | March 18, 2009Memory has intrigued us for millenia, and is today one of the most active areas of neuroscience research. Much of this research has aimed to understand how memories are laid down, and a picture of how this happens is beginning to emerge. Hundreds of studies published over the past few decades provide evidence that memory formation involves widespread reorganization of connections in the brain.
The vast majority of memory research has therefore pertained to the neural processes which occur after the event that is being memorized. More recently, though, a number of studies have suggested that…
neurophilosophy | March 16, 2009We all know what it means to be conscious. You are, of course, conscious right now - if you were not, you would be unable to read this. And while you read, you will be conscious of the words on your computer screen; of tactile sensations originating from the mouse you are holding and the chair you are sitting in; and possibly of some background noise, even though you are not explicitly paying attention to it.
Nevertheless, the term consciousness still has no adequate definition, and the question of how it is generated by the brain is the biggest challenge to modern neuroscience. Researchers…