neuroscience
edyong | April 3, 2009
Say the word 'statistician' and most people might think of an intelligent but reclusive person, probably working in a darkened room and almost certainly wearing glasses. But a new study shows that a monkey in front of a monitor can make a reasonably good statistician too.
Tianming Yang and Michael Shadlen from the University of Washington found that rhesus macaques can perform simple statistical calculations, and even watched their neurons doing it. Psychologists often train animals to learn simple tasks, where the right choice earns them a reward and the wrong one leaves them empty-…
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.…
edyong | March 30, 2009For any animal, it pays to be able to spot other animals in order to find mates and companions and to avoid predators. Fortunately, many animals move in a distinct way, combining great flexibility with the constraints of a rigid skeleton - that sets them apart from inanimate objects like speeding trains or flying balls. The ability to detect this "biological motion" is incredibly important. Chicks have it. Cats have it. Even two-day-old babies have it. But autistic children do not.
Ami Klim from Yale has found that two-year-old children with autism lack normal preferences for natural…
edyong | March 29, 2009Anyone who has played video games for too long is probably familiar with the sore, tired and dry eyes that accompany extended bouts of shooting things with rocket launchers. So it might come as a surprise that playing games could actually improve a key aspect of our eyesight.
Renjie Li from the University of Rochester found that intensive practice at shoot-em-ups like Unreal Tournament 2004 and Call of Duty 2 improved a person's ability to spot the difference between subtly contrasting shades of grey. In the real world, this "contrast sensitivity function" is reflected in the crispness of…
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)…
purepedantry | March 25, 2009I know this will be of interesting for about 1 in a hundred of you, but there is a REALLY good review of hippocampal and parahippocampal region connectivity in April's Nature Review Neuroscience. Of special interest, there is an interactive .pdf in the supplementary information where you can identify the connections between one region to every other region. Also, they discuss the functions of the entorhinal cortex and the subiculum from the point of view of update anatomy.
(Unfortunately behind a subscription wall, but I feel confident that anyone who understood a word of what I just said…
edyong | March 25, 2009We're used to thinking of neglect as a lack of appropriate care, but to a neuroscientist, it has a very different meaning. "Spatial neglect" is a neurological condition caused by damage to one half of the brain (usually the right), where patients find it difficult to pay attention to one half of their visual space (usually the left).
This bias can affect their mental images too. If neglect patients are asked to draw clocks, many only include the numbers from 12 to 6, while some shunt all the numbers to the right side. When two famous neglect patients were asked to describe a familiar square…
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…
neurophilosophy | March 12, 2009Spatial 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 representations are encoded in the medial temporal lobe, and numerous studies implicate the hippocampus in particular as being crucial for the formation of spatial memories. Information about the environment is believed to be encoded by large populations of neurons distributed…
edyong | March 12, 2009A couple of weeks ago, I wrote about propranolol, a drug that can erase the emotion of fearful memories. When volunteers take the drug before recalling a scary memory about a spider, it dulled the emotional sting of future recollections. It's not, however, a mind-wiping pill in the traditional science-fiction sense, and it can't erase memories as was so widely reported by the hysterical mainstream media.
The research that's published today is a different story. Jin-Hee Han from the University of Toronto has indeed found a way to erase a specific fearful memory, but despite the superficial…
ksharpe | March 12, 2009Originally posted by Brian Switek
On March 10, 2009, at 11:14 AM
In 1857 Richard Owen proposed that our species, Homo sapiens, belonged to a distinct subclass separate from all other primates. He called this new group the Archencephala and based it as much upon human powers of reason as minute neuroanatomical differences between apes and humans. What's more, our "extraordinarily developed brain[s]" not only placed us above all other creatures but gave us new moral responsibilities, and in closing Owen stated;
Thus [Man] fulfils his destiny as the master of this earth, and of the lower…
neurophilosophy | March 10, 2009One 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 pliable, like a piece of putty, so that each new experience makes a lasting impression upon it.
This phenomenon, referred to as synaptic (or neural) plasticity, involves reorganization of the connections between nerve cells, and is arguably the most important discovery in…
ksharpe | March 10, 2009Originally posted by Jessica Palmer
On March 7, 2009, at 11:00 PM
Brevity can be a creative coup. Consider Claire Evans' "Evolution of Life in 60 Seconds", which shoehorns our entire history into one minute: as the clock slowly ticks away, it makes me fear for a moment - implausible as it may seem - that it might run out before we evolve. Then there's the genius of Hamlet as Facebook updates (or Pride and Prejudice, though I don't find it nearly as good as Hamlet.) Maybe it's a symptom of our increasingly short attention spans, the acceleration of the news cycle, or simply the accumulation…
edyong | March 10, 2009If you wanted to turn a rat into a fearless critter, unfazed by cats or bigger rats, the best way would be to neutralise a small pair of tiny structures in its brain called the dorsal premammillary nuclei, orPMD. According to new research by Simone Motta at the University of Sao Paolo, these small regions, nestled within a rat's hypothalamus, control its defensive instincts to both predators and other rats.
But not all neurons in the PMD are equal. It turns out that the structures are partitioned so that different bits respond to different threats. The front and side parts (the ventrolateral…
neurophilosophy | March 9, 2009More 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 of Freud's theories have long since been discredited, but they remain influential to this day. Repression in particular has proven to be extremely controversial. It has attracted much attention in the context of the many legal cases…
terrasig | March 9, 2009
I'm very proud today to see one of my formative professors, Dr Fulton Crews, quoted extensively in a USAToday article on a new, web-based alcohol awareness initiative, "Rethinking Drinking," from NIH's National Institute for Alcohol Abuse and Alcoholism (NIAAA) Division of Treatment and Recovery Research.
While many associate heavy drinking with liver problems, it can also increase the risk for heart disease, sleep disorders, depression, stroke and stomach bleeding. Consumed during pregnancy, it can cause fetal brain damage, says Fulton Crews, director of the Bowles Center for Alcohol…