MEMORY is one of the biggest enduring mysteries of modern neuroscience, and has perhaps been researchered more intensively than any other aspect of brain function. The past few decades have yielded a great deal of knowledge about the cellular and molecular mechanisms of memory, and it is now widely believed that memories are formed as a result of biochemical changes which ultimately lead to the strengthening of connections between nerve cells.
However, it is also clear that memories are not enco........ Read more »
Chen, G., Wang, L., & Tsien, J. (2009) Neural Population-Level Memory Traces in the Mouse Hippocampus. PLoS ONE, 4(12). DOI: 10.1371/journal.pone.0008256
SYNAESTHESIA is a neurological condition in which there is a merging of the senses, so that activity in one sensory modality elicits sensations in another. Although first described by Francis Galton in the 1880s, little was known about this condition until recently. A rennaissance in synaesthesia research began about a decade ago; since then, three previously unrecognized forms of the condition have been described, and a possible explanation for how it arises have been put forward.
Of all the f........ Read more »
Jarick, M., Dixon, M., Stewart, M., Maxwell, E., & Smilek, D. (2009) A different outlook on time: Visual and auditory month names elicit different mental vantage points for a time-space synaesthete. Cortex, 45(10), 1217-1228. DOI: 10.1016/j.cortex.2009.05.014
Simner, J., Mayo, N., & Spiller, M. (2009) A foundation for savantism? Visuo-spatial synaesthetes present with cognitive benefits. Cortex, 45(10), 1246-1260. DOI: 10.1016/j.cortex.2009.07.007
IMAGINE sitting in a noisy restaurant, across the table from a friend, and having a conversation with them 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 rand........ Read more »
Chandrasekaran, B., Hornickel, J., Skoe, E., Nicol, T., & Kraus, N. (2009) Context-Dependent Encoding in the Human Auditory Brainstem Relates to Hearing Speech in Noise: Implications for Developmental Dyslexia. Neuron, 64(3), 311-319. DOI: 10.1016/j.neuron.2009.10.006
A 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........ Read more »
Wu, C.-T., et al. (2009) The Temporal Interplay between Conscious and Unconscious Perceptual Streams. Curr. Biol. . info:/10.1016/j.cub.2009.10.017
FOLLOWING 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 their 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 ........ Read more »
Moseley, G., & Brugger, P. (2009) Interdependence of movement and anatomy persists when amputees learn a physiologically impossible movement of their phantom limb. Proc. Nat. Acad. Sci. DOI: 10.1073/pnas.0907151106
THE humble fruit fly (Drosophila melanogaster) has the ability to learn and remember, and to make predictions about the outcome of its behaviours on the basis of past experience. Compared to a human brain, that of the fruit fly is relatively simple, containing approximately 250,000 cells. Even so, little is known about the anatomical basis of memory formation. The neural circuitry underlying memories in these insects has now been dissected. In an elegant new study published in the journal ........ Read more »
Claridge-Chang, A., Roorda, R., Vrontou, E., Sjulson, L., Li, H., Hirsh, J., & Miesenböck, G. (2009) Writing Memories with Light-Addressable Reinforcement Circuitry. Cell, 139(2), 405-415. DOI: 10.1016/j.cell.2009.08.034
USING an inventive new method in which mice run through a virtual reality environment based on teh 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 to a better understanding of how spatial information is encoded at the cellular level.
Read the rest of this post... | Read the c........ Read more »
Harvey, C., Collman, F., Dombeck, D., & Tank, D. (2009) Intracellular dynamics of hippocampal place cells during virtual navigation. Nature, 461(7266), 941-946. DOI: 10.1038/nature08499
THINKING 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........ Read more »
Sahin, N., Pinker, S., Cash, S., Schomer, D., & Halgren, E. (2009) Sequential Processing of Lexical, Grammatical, and Phonological Information Within Broca's Area. Science, 326(5951), 445-449. DOI: 10.1126/science.1174481
ATHLETES who are on a winning streak often claim that they perceive their targets to be bigger than they actually are. After a run of birdies, for examples, golfers sometimes say that the cup appeared to be the size of a bucket, and baseball players who have a hit a few home runs say that the ball is the size of a grapefruit. Conversely, targets are often reported to be smaller than they actually are by athletes who are performing badly.
Research carried out in the past 5 years suggests that th........ Read more »
Witt, J., & Dorsch, T. (2009) Kicking to bigger uprights: Field goal kicking performance influences perceived size. Perception, 38(9), 1328-1340. DOI: 10.1068/p6325
SECOND LIFE is an online "virtual world" which enables users to create a customised avatar, or digital persona, with which they interact with each other. Since its launch just over 6 years ago, it has become incredibly popular, with millions of "residents" now using it regularly to meet others, interact with them, and even to have sex. Users have also established virtual universities, businesses and a virtual economy.
Now, imagine a futuristic version of Second Life, in which avatars can trans........ Read more »
Slater, M. et al. (2009) Inducing illusory ownership of a virtual body . Front. Neurosci. info:/
VISION is now well known to modulate the senses of touch and pain. For example, various studies have shown that looking at oneself being touched has the opposite effect - it 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 making a limb look larger or smaller than it actually using binoculars can respectively enhance and diminish painful sensation........ Read more »
Longo, M., Betti, V., Aglioti, S., & Haggard, P. (2009) Visually Induced Analgesia: Seeing the Body Reduces Pain. Journal of Neuroscience, 29(39), 12125-12130. DOI: 10.1523/JNEUROSCI.3072-09.2009
SEVERAL hundred species of fish have evolved the ability to generate electric fields, which they use to navigate, communicate and home in on prey. But this ability comes at a cost - the electric field is generated continuously throughout life, so consumes a great deal of energy, and it can also attract predators which are sensitive to it. Electrogenic fish species therefore utilize various strategies to save energy and to minimize the likelihood of being detected. Some generate irregular pulses ........ Read more »
Markham, M., McAnelly, M., Stoddard, P., & Zakon, H. (2009) Circadian and Social Cues Regulate Ion Channel Trafficking. PLoS Biology, 7(9). DOI: 10.1371/journal.pbio.1000203
REMOTE-CONTROLLED insects may sound like the stuff of science fiction, but they have already been under development for some time now. In 2006, for example, the Defense Advanced Research Projects Agency (DARPA, the Pentagon's research and development branch) launched the Hybrid Insect Micro-Electro-Mechanical Systems project, whose ultimate aim is turn insects into unmanned aerial vehicles.Such projects provide proof of principle, but have met with limited success. Until now, that is. In the ope........ Read more »
Sato, H., et al. (2009) Remote Radio Control of Insect Flight. Front. Integr. Neurosci. , 3(24). info:/
THE vegetative and minimally conscious states are examples of what are referred to as disorders of consciousness. Patients in these conditions are more or less oblivious to goings-on in their surroundings - they exhibit few, if any, signs of conscious awareness, and are usually unable to communicate in any way. It is, therefore, extremely difficult to establish what these patients are experiencing, and the consciousness disorders are among the least understood, and most commonly diagnosed, condi........ Read more »
Bekinschtein, T., Shalom, D., Forcato, C., Herrera, M., Coleman, M., Manes, F., & Sigman, M. (2009) Classical conditioning in the vegetative and minimally conscious state. Nature Neuroscience. DOI: 10.1038/nn.2391
LANGUAGE contains many sayings which link our feelings and behaviour towards others to temperature. We might, for example, hold "warm feelings" for somebody, and extend them a "warm welcome", while giving somebody else "the cold shoulder" or "an icy stare". Why is that we have so many metaphors which relate temperature to social distance? According to the cognitive scientist George Lakoff, we judge others on the basis of warmth because abstract concepts, such as affection, are firmly grounded in........ Read more »
Ijzerman H. , & Semin G.R. (2009) The Thermometer of Social Relations: Mapping Social Proximity on Temperature. Psychological science. PMID: 19732385
A paper by researchers from Princeton University, just published in the open access journal PLoS One, describes a new virus-based technique for probing the connections between neurons while simultaneously monitoring their activity in live animals. Various methods are available for studying the activity of neurons and how they are connected to one another, but examining the co-ordinated activity of multiple nerve cells in neural circuits has, until now, posed a big challenge, because none of them........ Read more »
Granstedt, A., Szpara, M., Kuhn, B., Wang, S., & Enquist, L. (2009) Fluorescence-Based Monitoring of In Vivo Neural Activity Using a Circuit-Tracing Pseudorabies Virus. PLoS ONE, 4(9). DOI: 10.1371/journal.pone.0006923
THIS short film clip shows two images of the same scene. Watch it carefully, and see if you can spot the subtle difference between the two. 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 ........ Read more »
Hannula, D.E. . (2009) The Eyes Have It: Hippocampal Activity Predicts Expression of Memory in Eye Movements. Neuron, 1-8. info:/
THE retina has an inverted structure which seems ill-suited to its function: the rod and cone cells, which are sensitive to light, and which convert light energy into electrical impulses, point backwards and are located at the back of the retina, so that light entering the eye has to pass through several layers of irregularly organized cells before it reaches them. The retina also contains nerve fibres which are positioned perpendicular to the path of light entering the eye, and many of the stru........ Read more »
Franze, K., Grosche, J., Skatchkov, S., Schinkinger, S., Foja, C., Schild, D., Uckermann, O., Travis, K., Reichenbach, A., & Guck, J. (2007) Muller cells are living optical fibers in the vertebrate retina. Proceedings of the National Academy of Sciences, 104(20), 8287-8292. DOI: 10.1073/pnas.0611180104
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 eeks 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 st........ Read more »
Catania, K. (2006) Olfaction: Underwater 'sniffing' by semi-aquatic mammals. Nature, 444(7122), 1024-1025. DOI: 10.1038/4441024a
Catania, K., & Remple, F. (2005) Asymptotic prey profitability drives star-nosed moles to the foraging speed limit. Nature, 433(7025), 519-522. DOI: 10.1038/nature03250
NOT so long ago, the idea that birds might possess some form of what we call intelligence seemed quite ridiculous.Yet in recent years, this view has changed dramatically, with numerous studies showing that some bird species are capable of complex cognition. Members of one family of birds in particular - the Corvidae, which includes crows, rooks and ravens - have an ability to make and use tools which is at least as sophisticated as that of chimpanzees.
Two new studies, published this week, prov........ Read more »
Wimpenny, J., Weir, A., Clayton, L., Rutz, C., & Kacelnik, A. (2009) Cognitive Processes Associated with Sequential Tool Use in New Caledonian Crows. PLoS ONE, 4(8). DOI: 10.1371/journal.pone.0006471
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