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  • May 10, 2011
  • 04:10 PM

Sleepy brain waves predict dream recall

by Mo in Neurophilosophy

THE patterns of brain waves that occur during sleep can predict the likelihood that dreams will be successfully recalled upon waking up, according to a new study published in the Journal of Neuroscience. The research provides the first evidence of a 'signature' pattern of brain activity  associated with dream recall. It also provides further insight into the brain mechanisms underlying dreaming, and into the relationship between our dreams and our memories.

Cristina Marzano of the Sleep Psychophysiology Laboratory at the University of Rome and her colleagues recruited 65 students, selected on the basis of their sleeping habits. All of them had a regular sleep 'routine', going to bed at around the same time, and sleeping for an average of seven-and-a-half hours, every night. For the study, the participants slept for two consecutive nights in a sound-proof, temperature-controlled room in the lab. They were left to sleep uninterrupted on the first night, so that they would get accustomed to the new surroundings. 
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Marzano, C., Ferrara, M., Mauro, F., Moroni, F., Gorgoni, M., Tempesta, D., Cipolli, C., & De Gennaro, L. (2011) Recalling and Forgetting Dreams: Theta and Alpha Oscillations during Sleep Predict Subsequent Dream Recall. Journal of Neuroscience, 31(18), 6674-6683. DOI: 10.1523/JNEUROSCI.0412-11.2011  

  • May 4, 2011
  • 10:50 AM

Speed of illusory body movements alters the passage of time

by Mo in Neurophilosophy

YOUR brain has a remarkable ability to extract and process biological cues from the deluge of visual information. It is highly sensitive to the movements of living things, especially those of other people - so much so that it conjures the illusion of movement from a picture of a moving body. Although static, such pictures trigger dynamic representations of the body, 'motor images' containing information about movement kinematics and timing. Researchers at the Institute of Cognitive Neuroscience in London now show that biological motion is processed unconsciously, and that the speed of apparent motion alters the perception of time.
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  • April 28, 2011
  • 02:00 PM

Box jellyfish stable-eyes vision to hunt prey

by Mo in Neurophilosophy

Ernst Haeckel's Kunstformen der Natur (Artforms of Nature) was a landmark in biological illustration. Published in 1904, it was lavishly illustrated with 100 exquisitely detailed lithographic plates, including this one, showing nine different species of cubomedusae, or box jellyfish.It has been known, since around the time that Haeckel's masterpiece was published, that box jellyfish have a unique visual system which is more sophisticated than that of other jellyfish species. They boast an impressive set of 24 eyes of four different types, which are clustered within bizarre sensory appendages that dangle from the cube-shaped umbrella. The known light-guided behaviours of these organisms are, however, relatively simple, so exactly why they possess such an elaborate array of eyes was somewhat puzzling.A group of Scandinavian researchers working in the Carribean now report that one of the box jelly's eye types is highly specialized to peer up towards the water surface at all times, so that it can use terrestrial landmarks to navigate towards its prey.
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  • March 25, 2011
  • 09:55 AM

Gut bacteria may influence thoughts and behaviour

by Mo in Neurophilosophy

THE human gut contains a diverse community of bacteria which colonize the small intestine in the days following birth and vastly outnumber our own cells. These intestinal microflora constitute a virtual organ within an organ and influence many bodily functions. Among other things, they aid in the uptake and metabolism of nutrients, modulate the inflammatory response to infection, and protect the gut from other, harmful micro-organisms. A new study by researchers at McMaster University in Hamilton, Ontario now suggests that gut bacteria may also influence behaviour and cognitive processes such as memory by exerting an effect on gene activity during brain development.

Jane Foster and her colleagues compared the performance of germ-free mice, which lack gut bacteria, with normal animals on the elevated plus maze, which is used to test anxiety-like behaviours. This consists of a plus-shaped apparatus with two open and two closed arms, with an open roof and raised up off the floor. Ordinarily, mice will avoid open spaces to minimize the risk of being seen by predators, and spend far more time in the closed than in the open arms when placed in the elevated plus maze.
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  • March 7, 2011
  • 10:05 AM

Artificial nerve grafts made from spider silk

by Mo in Neurophilosophy

EVERY year, hundreds of thousands of people suffer from paralyzed limbs as a result of peripheral nerve injury. Recently, implantation of artificial nerve grafts has become the method of choice for repairing damaged peripheral nerves. Grafts can lead to some degree of functional recovery when a short segment of nerve is damaged. But they are of little use when it comes to regenerating nerves over distances greater than a few millimeters, and such injuries therefore often lead to permanent paralysis. 

Now though, surgeons from Germany have made what could be a significant advance in nerve tissue engineering. They have developed artificial nerve grafts made from hollowed-out pig veins filled with spider silk fibres and, in a series of animal experiments, showed that the grafts can enhance the regeneration of peripheral nerves over distances of up to 6cm. Their findings have just been published in the open access journal PLoS One.
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Radtke, C., Allmeling, C., Waldmann, K., Reimers, K., Thies, K., Schenk, H., Hillmer, A., Guggenheim, M., Brandes, G., & Vogt, P. (2011) Spider Silk Constructs Enhance Axonal Regeneration and Remyelination in Long Nerve Defects in Sheep. PLoS ONE, 6(2). DOI: 10.1371/journal.pone.0016990  

  • March 3, 2011
  • 10:25 AM

Return of the brain-controlling zombie-ant parasitic fungi

by Mo in Neurophilosophy

A dead ant infected with a parasitic Cordyceps fungus (David P. Hughes).A team of entomologists working in the Brazilian rain forest has discovered four new species of parasitic Cordyceps fungi, which infect insects and manipulate the behaviour of their hosts in order to disperse their spores as widely as possible.The modus operandi of the Cordyceps fungi is reminiscent of the famous chest-bursting scene in Ridley Scott's movie Alien. Microscopic spores infiltrate the host via the spiracles - the holes in the exoskeleton through which insects breathe - and the fungus begins feeding on its non-vital organs.When it is ready to release its spores, Cordyceps brainwashes its host: its filaments grow into the insect's brain, and release chemicals that cause it to climb a nearby plant and attach itself near the top by biting onto a leaf or stem. (Exactly how the chemicals work is unknown; they may interfere with the host's geomagnetic sense.) The host is then killed, and a mushroom containing spores sprouts from the top of its head. Read the rest of this post... | Read the comments on this post...... Read more »

  • March 2, 2011
  • 08:35 AM

Tough and tender: How touch affects sex categorization

by Mo in Neurophilosophy

LOOK at the photograph on the right. Does it show the face of a man or a woman? There's no right answer - the photo has been manipulated to look sexually ambiguous and can be perceived as either. But according to a recent study published in the journal Psychological Science, the sense of touch can influence how you perceive and categorize the face.Last year a team of European psychologists found that bodily movements alter the recollection of emotional memories, and an American group showed that the sense of touch influences social judgements and decisions. The new study adds to the growing body of evidence for embodied cognition, which refers to the way in which our thought processes are grounded in the body and the sensations arising from it. Read the rest of this post... | Read the comments on this post...... Read more »

  • July 31, 2010
  • 01:35 PM

Motor imagery enhances object recognition

by Mo in Neurophilosophy

THOUGHTS and actions are intimately linked, and the mere thought of an action is much like actually performing it. The brain prepares for an action by generating a motor simulation of it, praticising its execution of the movements by going through the motions invisibly. Seeing a manipulable object such as a tool, for example, automatically triggers a simulation of using it - a mental image of reaching out and grasping it with the hand that is nearest to the handle.  

Motor simulations and movements are known to influence thought processes. Magnetic stimulation of the motor cortex influences the processing of words related to arm and leg action, whereas polonged movements in one direction slow the comprehension of sentences related to movements in the other. Psychologist Jessica Witt of the Action-Modulated Perception Laboratory at Purdue University and her colleagues now provide further evidence of this link - in a study published online in the journal Psychological Science, they show that motor simulations may enhance the recognition of tools.
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  • July 22, 2010
  • 10:15 AM

Feeling blue, seeing gray: Reduced contrast sensitivity as a marker for depression

by Mo in Neurophilosophy

DEPRESSION has long been associated with vision - and to colour perception in particular - and the link between them is evident in everyday language. Depression is, of course, often referred to as "feeling blue", and those who suffer from it are sometimes told to "lighten up". The link can be found in art, too - Picasso's so-called "Blue Period", for example, which was brought on by the suicide of his close friend Carlos Casagemas, is characterised by a series of striking paintings in shades of cold blue, which express the deep melancholy he felt at the time.

Although the association between depression and colour is largely metaphorical, there is actually some evidence that they are closely linked. The most recent comes from a new study by German researchers published in the journal Biological Psychiatry. The study shows that depressed people have reduced sensitivity to contrast, and therefore that they may perceive the world differently from others. It also suggests that depression can be diagnosed by objective measurements of electrical activity in the eye. Read the rest of this post... | Read the comments on this post...... Read more »

  • July 15, 2010
  • 10:41 AM

Researchers create 'lesbian' mice by deleting a single gene

by Mo in Neurophilosophy

DELETION of a single gene switches the sexual orientation of female mice, causing them to engage in sexual behaviour that is typical of males. Korean researchers found that deleting the FucM gene, which encodes an enzyme called fucose mutarotase, causes masculinization of the mouse brain, so that female mice lacking the gene avoid the advances of males and try to mate with other females instead. The findings probably have little relavence to human sexual orientation, however.

FucM is one of a family of enzymes involved in rearranging the atoms in small sugar molecules called monosaccharrides. In 2007, Chankyu Park of the Korea Advanced Institute of Science and Technology and his colleagues reported that these rearrangements facilitate the incorporation of the monosaccharide fucose into cellular proteins. This process is one of numerous chemical modifications that are well known to regulate the function of proteins, but the biological significance of FucM function in mammals was until now unclear.
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  • July 9, 2010
  • 02:00 PM

Nanomagnetic remote control of animal behaviour

by Mo in Neurophilosophy

MAGNETIC nanoparticles targeted to nerve cell membranes can be used to remotely control cellular activity and even the simple reflex behaviours of nematode worms, according to research by a team of biophysicists at the University of Buffalo. The new method, which is described in the journal Nature Nanotechnology, could be very useful for investigating how cells interact in neuronal networks, and may eventually lead to new therapies for cancer and diabetes.
Heng Huang and her colleagues synthesized manganese-iron nanoparticles, each just 6 millionths of a millimeter in diameter, and coated with the bacterial protein straptavidin attached to a fluorescent molecule called DyLight549. Strepdavidin binds another molecule, much like a key fits into a lock, enabling specified cells to be targeted, while DyLight549 acts like a molecular thermometer, whose fluoresence intensity changes with temperature.
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  • July 2, 2010
  • 05:43 PM

Scared by the light

by Mo in Neurophilosophy

WHO could have guessed that a protein isolated from pond scum would transform the way researchers investigate the brain? The protein, called channelrhodopsin (ChR), is found in algae and other microbes, and is related to the molecules in the human eye that capture light particles. Both versions control the electrical currents that constantly flow in and out of cells, and which are critical for generating the nervous impulses generated by neurons. Unlike its human equivalent, algal ChR controls the currents directly because it forms a pore that spans the cell membrane. When expressed in neurons, it renders the cells sensitive to light, and they can be switched on or off very precisely using lasers.This discovery led to the emergence of a new field called optogenetics. Early studies showed that the technique can be used to control the behaviour of small organisms such as nematode worms and fruit flies. Last year, Karl Deisseroth's group at Stanford University demonstrated, for the first time, that it can also be used to control reward and motivation behaviours in mice. Josh Johansen of the Center for Neural Science at New York University and his colleagues have now taken this one step further. Working in collaboration with Deisseroth, they show that optogenetics can also be used to induce a simple form of associative learning called fear conditioning. Read the rest of this post... | Read the comments on this post...... Read more »

Johansen, J., Hamanaka, H., Monfils, M., Behnia, R., Deisseroth, K., Blair, H., & LeDoux, J. (2010) Optical activation of lateral amygdala pyramidal cells instructs associative fear learning. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1002418107  

  • June 30, 2010
  • 05:36 PM

Neural basis of spatial navigation in the congenitally blind

by Mo in Neurophilosophy

FOR most of us, the ability to navigate our environment is largely dependent on the sense of vision. We use visual information to note the location of landmarks, and to identify and negotiate obstacles. These visual cues also enable us to to keep track of our movements, by monitoring how our position changes relative to landmarks and, when possible, our starting point and final destination. All of this information is combined to generate a cognitive map of the surroundings, on which successful navigation of that environment later on depends.

Despite the importance of vision for navigation, congenitally blind people - those born blind - can still generate neural representations of space. Exactly how is unclear, but it is thought to be by using a combination of touch, hearing and smell, and some are even known to use echolocation. Spatial navigation in the congenitally blind is therefore thought to involve different brain networks than those engaged in sighted people. A team of Danish researchers  now report, however, that the mechanisms underlying spatial navigation in the blind are much the same as those in sighted people, due to the brain's remarkable ability to reconfigure itself. 

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  • June 25, 2010
  • 12:05 PM

Touch influences social judgements and decisions

by Mo in Neurophilosophy

APPLYING for a job? The weight of the clipboard to which your CV is attached may influence your chances of getting it. Negotiating a deal? Sitting in a hard chair may lead you to drive a harder bargain. Those are two of the surprising conclusions of a study published in today's issue of Science, which shows that the physical properties of objects we touch can unconsciously influence our first impressions of other people and the decisions we make about them.

Josh Ackerman of the Sloan School of Management at MIT, and psychologists Chris Nocera and John Bargh of Harvard and Yale Universities, respectively, performed a series of six experiments designed to investigate whether or not the weight, texture and hardness of objects can influence our judgements and decisions about unrelated events and situations. Their findings provide yet more evidence for the embodied cognition hypothesis, which states that bodily perceptions can exert a strong influence on the way we think.
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  • June 24, 2010
  • 08:00 PM

Movable micromotor brain implants

by Mo in Neurophilosophy

BRAIN implants containing microelectrodes are used widely in the laboratory and clinic, both to stimulate nerve cells and to record their activity. Researchers routinely implant electrode arrays into the brains of rodents to investigate the neuronal activity associated with spatial navigation, or into monkeys' brains to gain a better understanding of the mechanisms of motor control. As a result, we now have brain-computer interfaces that can help paralysed patients to communicate or control a prosthetic limb. Electrode arrays can also be used to assess vegetative patients, and to treat conditions such as Parkinson's Disease and depression.

In most instances, keeping the electrodes in place for long periods of time is crucial. But this is difficult, for a number of reasons. In experiments involving freely moving rats, for example, the animal's movements can cause the electrodes to be displaced, and when they do stay in place, the electrodes become gradually become ensheathed with glial cells, causing the signal to deteriorate with time. The devices have to be re-adjusted regularly, and their decoding algorithms recalibrated, to maintain the signal strength. Implants containing movable electrodes can potentially overcome these problems. The latest such device (described in a new paper in the journal Frontiers in Neuroengineering)  is the most advanced yet. It uses microelectromechanical systems (MEMS) to move the electrodes up and down, and can record stably for up to 6 months.

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Jackson, N. et al. (2010) Long-term neural recordings using MEMS based movable microelectrodes in the brain. Frontiers Neuroeng. info:/

  • June 16, 2010
  • 05:33 PM

Obesity linked to brain shrinkage and dementia

by Mo in Neurophilosophy

THE dangers of obesity are very well known. Being overweight is associated with an increased risk of coronary heart disease and stroke, the two leading causes of death in the Western world. Gout is more common in overweight people, with the risk of developing the condition increasing in parallel with body weight. Obese people are twice as likely to develop type 2 diabetes as those who are not overweight, and being overweight is also associated with several types of cancer. The list goes on...

Less well known is the effect of obesity on the brain. In the past few years, however, it has emerged that being overweight in middle age is linked to an increased risk of Alzheimer's Disease and other forms of dementia. Two new studies strengthen this association: the first, just published in the Annals of Neurology, shows that abdominal fat is linked to reduced brain volume in otherwise healthy middle-aged adults. The second, published last month in Proceedings of the National Academy of Sciences, shows that this reduction is associated with a common variant of an obesity-related gene.
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Debette, S., Beiser, A., Hoffmann, U., DeCarli, C., O'Donnell, C., Massaro, J., Au, R., Himali, J., Wolf, P., Fox, C.... (2010) Visceral fat is associated with lower brain volume in healthy middle-aged adults. Annals of Neurology. DOI: 10.1002/ana.22062  

  • June 7, 2010
  • 07:55 PM

Hair pulling is a neuroimmunological condition

by Mo in Neurophilosophy

TRICHOTILLOMANIA (or hair pulling) is a condition characterised by excessive grooming and strong, repeated urges pull out one's own hair. It is classified as an obsessive-compulsive disorder (OCD), and is relatively common, affecting about 2 in 100 people. Sufferers normally feel an increasing sense of tension before pulling out their scalp hair, facial hair, and even pubic hair, eyelashes or eyebrows. This provides gratification, but only briefly.

Hair pulling is usually thought of as being psychological in origin, but an intruiging new study now suggests that it occurs as a result of defects in the immune system. The study, which is published in the journal Neuron, shows that excessive grooming and hair pulling occur in mice because of reduced numbers of microglial cells, which are critical  for the brain's immune response. It also suggests - very unexpectedly - that bone marrow transplants may be an effective treatment for trichotillomania in humans.
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Chen, S., Tvrdik, P., Peden, E., Cho, S., Wu, S., Spangrude, G., & Capecchi, M. (2010) Hematopoietic Origin of Pathological Grooming in Hoxb8 Mutant Mice. Cell, 141(5), 775-785. DOI: 10.1016/j.cell.2010.03.055  

  • May 27, 2010
  • 02:18 PM

Apparent motion steers the wandering mind

by Mo in Neurophilosophy

DAYDREAMING is a critical component of conscious experience. The mind can perform mental time travel - it occasionally strays from the present moment, to recollect an experience from the near or distant past, or to imagine an event that has not yet taken place. We know that imagining a future event is dependant on memory, because patients with amnesia cannot imagine new experiences. It involves piecing together fragments of past experiences to generate a plausible simulation of what might happen. This may have been an important development in human evolution, as it enables us anticipate a likely outcome and to plan the best possible course of action. 

Space and time are intimately linked in the mind, and this is reflected in our metaphors. We often say that we are thinking back to a past event, or looking forward to one that will take place in the future. But the mind and body are also closely linked: think about a past experience, and you might find yourself moving backwards. A new study suggests that this can be reversed, by showing that apparent motion can influence the direction of the mind's wanderings. Thus, moving backwards could evoke long lost memories, while moving forward might make you think about the future.

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Miles, L. K., et al. (2010) The Meandering Mind: Vection and Mental Time Travel. PLoS One. info:/

  • May 21, 2010
  • 05:48 AM

Optogenetic fMRI

by Mo in Neurophilosophy

OF all the techniques used by neuroscientists, none has captured the imagination of the general public more than functional magnetic resonance imaging (fMRI). The technique, which is also referred to as functional neuroimaging and, more commonly, "brain scanning", enables us to peer into the human brain non-invasively, observe its workings in near-real time, and correlate specific thought processes or stimuli to activity in particular regions. fMRI data affect the way in which people perceive scientific results: colourful images of the brain have persuasive power, making the data that accompanies them seem more credible.

Functional neuroimaging is used widely by researchers, too, with tens of thousands of research papers describing fMRI studies being published in the past decade. Yet, a big question mark has been hanging over the validity of the technique for over a year and, furthermore, the way in which fMRI data are interpreted has also been called into question..Using a novel combination of fMRI and a recently developed state-of-the-art technique called optogenetics, researchers now provide the first direct evidence that the fMRI signal is a valid measure of brain activity.
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  • May 14, 2010
  • 10:40 AM

Near misses fuel gambling addiction

by Mo in Neurophilosophy

GAMBLING is extremely popular, with lottery tickets, casinos, slot machines, bingo halls and other forms of the activity generating revenues of more than £80 billion each year in the UK alone. For most people, gambling is nothing more than an entertaining way to pass the time. But for some, it becomes a compulsive and pathological habit - they spend increasing amounts of time gambling, because tolerance builds up quickly, and experience withdrawal symptoms when they aren't gambling.

The terms "tolerance" and "withdrawal" are normally associated with drug addiction, and indeed pathological gambling is now considered as being akin to substance abuse. We know, for example, that monetary wins activate the brain's reward circuitry. In pathological gamblers, however, these responses are dampened, so that increasingly larger wins are needed to produce the same rewarding effects. And according to a new study published in the Journal of Neuroscience, near misses fuel the habit in regular gamblers, because they are almost as rewarding as wins.
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