Neurophilosophy

Archives for March, 2009

Voluntary amputation and extra phantom limbs

If 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…

Optogenetics 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…

The 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…

Memory 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…

Igniting the flame of consciousness

We 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…

Spatial navigation is a complex mental task which is strongly dependent upon memory. As we make our way around a new environment, we look for easily recognisable landmarks and try to remember how their locations are related in space, so that when we return to it we can negotiate our path.  We know that spatial…

One of the central dogmas of neuroscience, which persisted for much of the history of the discipline, was that the adult human brain is immalleable, and could not change itself once fully developed. However, we now know that this is not the case: rather than setting like clay placed into a mould, the brain remains…

Brain mechanisms of Freudian repression

More than 100 years ago, Sigmund Freud, the father of psychoanalysis, proposed a mechanism called repression, whereby desires and impulses are actively pushed into the unconscious mind. For Freud, repression was a defence mechanism – the repressed memories are often traumatic in nature, but, although hidden, they continue to exert an effect on behaviour. Many…

Anatomy of a 300 million year-old brain

Nervous tissue is extremely fragile, and so is very well protected. The brain, which has a jelly-like consistency, is encased in the skull, and is surrounded by cerebrospinal fluid, which acts to cushion it against blows that might cause it to come into contact with the inside of its bony case. Likewise, the spinal cord…

Amnesia in the movies

Despite occuring only rarely, amnesia (or memory loss) has featured often in Hollywood films for almost a century. By 1926, at least 10 silent films which used amnesia as a plot device had been made; more recent productions, such as 50 First Dates and Eternal Sunshine of the Spotless Mind, are therefore part of a…