A description of a study that demonstrates a 'virtual hand movement' illusion... Read more »
Sanchez-Vives MV, Spanlang B, Frisoli A, Bergamasco M, & Slater M. (2010) Virtual hand illusion induced by visuomotor correlations. PloS one, 5(4). PMID: 20454463
In the brain, there are highly ordered representations of sensory input. The existence of orientation columns in the visual cortex where columns of neurons situated next to each other respond to slightly different stimulus orientations and the barrel cortex in S1 where each barrel faithfully receives inputs from one whisker are testimony to this. Recently two papers in the same issue of Nature Neuroscience dealt with the fidelity of sensory representations in the auditory cortex. Rothschild et al. and Bandyopadhyay et al. used in-vivo two photon microscopy to map tone evoked activity in the primary auditory cortex (A1). This is done by bulk loading a large area of the cortex with a membrane permeable calcium dye. When a neuron that has taken up the dye fires an action potential, there is also a transient influx of calcium (related to synaptic transmission). The interaction of the calcium ions with the calcium indicator can be visualized under a two-photon microscope. Both studies showed, that unlike the visual and barrel cortices, the auditory cortex appears to have a tonotopic map that is fractured. Firstly, less than half the neurons were responsive, and even if they did respond, neurons with similar tuning curves were as likely to be located next to each other as neurons with very different tuning curves. Fig 1 (taken from a review by Castro and Kandler, Nature Neuroscience 2010) elaborates on this.Fig1a would be the classic tonotopic map where there is a smooth change in frequencies along the rostrocaudal axis with more rostral neurons coding for higher frequencies while more caudal neurons code for lower ones. Here, tonotopy is maintained on the local as well as the global scale. Fig 1b summarizes the results of Rothschild et al. and Bandyopadhyay et al. Although the tonotopic organisation is maintained on a more global scale, locally the map appears to be fractured (From Castro and Kandler, 2010)So why is the tonotopic map fractured? One possibility is that the thalamocortical projections from the auditory thalamus to A1 become scattered en route. Alternately, thalamocortical axons may be arranged tonotopically but resulting intra-cortical processing may result in the fractured nature of A1. To distinguish between these two possibilities, Bandyopadhyay et al labeled cells with two different calcium indicators, Fluo 4, a low affinity indicator that responds only to spikes in the cells, and OGB-1, a high affinity indicator that responds to subthreshold synaptic inputs into the cells. They found that subthreshold maps were more ordered in comparison to suprathreshold maps based on spiking (Fig 2).Fig2; Subthreshold and Suprathreshold maps (From Castro and Kandler, 2010)So what does all of this mean? Bandyopadhyay et al suggest that although two neighboring neurons may receive similar , correlated inputs, they may be part of different fine-scaled assemblies that could process inputs differently. Two adjacent cells may be selective for different input features or different stimulus attributes. Taken together, both studies indicate that frequency is perhaps not the most important feature coded by A1 neurons. Neither is intensity tuning or bandwidth. A1 neurons probably respond to meaningful stimuli and not just to simple sound parameters. This is supported by studies that have shown that A1 neurons are best driven by spectrally and temporally rich stimuli.References:Castro JB, & Kandler K (2010). Changing tune in auditory cortex. Nature neuroscience, 13 (3), 271-3 PMID: 20177415Rothschild, G., Nelken, I., & Mizrahi, A. (2010). Functional organization and population dynamics in the mouse primary auditory cortex Nature Neuroscience, 13 (3), 353-360 DOI: 10.1038/nn.2484Bandyopadhyay S, Shamma SA, & Kanold PO (2010). Dichotomy of functional organization in the mouse auditory cortex. Nature neuroscience, 13 (3), 361-8 PMID: 20118924... Read more »
Rothschild, G., Nelken, I., & Mizrahi, A. (2010) Functional organization and population dynamics in the mouse primary auditory cortex. Nature Neuroscience, 13(3), 353-360. DOI: 10.1038/nn.2484
Bandyopadhyay S, Shamma SA, & Kanold PO. (2010) Dichotomy of functional organization in the mouse auditory cortex. Nature neuroscience, 13(3), 361-8. PMID: 20118924
A novel area of circadian research is the influence of clock genes and circadian rhythms on the etiology of mood disorders. This area of research suggests a need for alternative therapeutic interventions, such as chronotherapy (using melatonin, bright light therapy, and adjusted sleep/wake schedules),that do not risk addiction by pharmacological treatments. ... Read more »
MCCLUNG, C. (2007) Circadian genes, rhythms and the biology of mood disorders. Pharmacology , 114(2), 222-232. DOI: 10.1016/j.pharmthera.2007.02.003
The big news this week in evolution is of course the sequencing of the Neanderthal genome, and the evidence that humans carry some DNA from our extinct cousins. The paper was published in Science yesterday, and has a total of 56 authors, including team leader Svante Pääbo.... Read more »
Cowburn (2010) suggests that to effectively deal with the problem of male sexual violence, we must pay closer attention to the role of masculinity in shaping harmful behaviours and attitudes.... Read more »
Cowburn, M. (2010) Invisible men: Social reactions to male sexual coercion - bringing men and masculinities into community safety and public policy. Critical Social Policy, 30(2), 225-244. DOI: 10.1177/0261018309358308
I am getting towards the end of my discussion of Philip McCann’s paper, “Economic geography, globalisation and New Zealand’s productivity paradox” .
In my last post on this topic, I discussed the importance of agglomeration economies for knowledge based production. Agglomeration in the modern economy is thought to maximise the efficiency and effectiveness of the [...]... Read more »
McCann, P. (2009) Economic geography, globalisation and New Zealand's productivity paradox. New Zealand Economic Papers, 43(3), 279-314. DOI: 10.1080/00779950903308794
Most of what we know about prehistoric North American atlatls comes from the many well-preserved examples found by Alfred Kidder and Samuel Guernsey in the early twentieth century in Basketmaker II rockshelters near Kayenta, Arizona. We know much more about atlatl use in Mesoamerica, where the atlatl was still widely used in the contact era, [...]... Read more »
Butler, B., & Osborne, D. (1959) Archaeological Evidence for the Use of Atlatl Weights in the Northwest. American Antiquity, 25(2), 215. DOI: 10.2307/277441
Fenenga, F., & Wheat, J. (1940) An Atlatl from the Baylor Rock Shelter, Culberson County, Texas. American Antiquity, 5(3), 221. DOI: 10.2307/275282
Neuman, R. (1967) Atlatl Weights from Certain Sites on the Northern and Central Great Plains. American Antiquity, 32(1), 36. DOI: 10.2307/278777
Palter, J. (1976) A New Approach to the Significance of the "Weighted" Spear Thrower. American Antiquity, 41(4), 500. DOI: 10.2307/279019
Swanton, J. (1938) Historic Use of the Spear-Thrower in Southeastern North America. American Antiquity, 3(4), 356. DOI: 10.2307/275622
Morgan, J., Darling, A., & Eisen, J. (2010). Metagenomic Sequencing of an In Vitro-Simulated Microbial Community PLoS ONE, 5 (4) DOI: 10.1371/journal.pone.0010209A new era for the design of metagenomic controls starts! Morgan et al. present the benchmarking of metagenomic tools using artificial "microbial communities" mixed up in the lab.The Hook...Metagenomics is a fancy name for what's actually a large and obscure toolbox of molecular biology procedures and computational algorithms that promises to help us in the understanding of whole, natural microbial communities. It is so exciting because it allows us to study organisms (bacteria and archaea specifically) that would otherwise remain unacknowledged because we cannot grow them in the lab. It also provides for the first time the opportunity to analyse whole natural communities, and not only sectors of it (like "granivorous community" or "photosynthetic guild"). The comparison of natural functional communities would help us understand a lot about how communities are assembled, how they evolve and change in time and how are they affected by external disturbances.Having said that, we still lack the tools to analyse such large databases and the quality standards to produce and compare metagenomes. This happens each time a new technology appears, because there has been not enough time to try and experiment with it as to accurately know its flaws. This is even worse with metagenomics since no whole community has ever been studied and so we don't really know or even suppose how our data should look like. Here's where Morgan et al. come to rescue with a very neat approach.The Setting...Their logic is simple and clear: since we do not have any community whose composition is completely known, let's make one. So they retrieved ten different microorganisms from the culture collections whose genomes have already been sequenced, and prepared aliquots so that they would have the same number of cells from each organism. Then they mixed them up, extracted the whole community DNA with three different DNA-extraction protocols and then sequenced four metagenome databases (one was replicated with an alternative sequencing method).The Bad...Surprisingly, none of the sequenced metagenomes reflected the original composition of the community mix. This can be caused for a number of reasons: the size of a genome and the number of genome copies per cell affect the probability of sequencing; differences in cell wall and matrix thickness and composition could prevent efficient DNA extraction; specific DNA segments might be harder to clone and/or sequence... When they compared between metagenomes, they found that most differences were due to the type of DNA extraction utilized. That is, the same community will result in different metagenomes when different DNA extraction methods are used. This also means that metagenomes obtained with different DNA extraction protocols should not be compared. Ever.It still puzzles me one thing: the love for BLAST. Even when they assigned each sequence to a specific organisms by "blasting" each read from the metagenomes to the ten complete genomes of the organisms in the mix, there's a large number of sequences that could not be mapped back to the source organism. Sure, there seems to be a phage infecting some cultures that was not in the sequenced genome. But it is surprising that there was a large number of reads that actually hit a Bacillus, when there were five Lactobacillus strains in the mix. My point is that BLAST is a very poor algorithm to recover precise hits, and the short lenght of the sequences reduce the taxonomic resolution attainable by it, misleading the results. If we add a really biased and incomplete reference database, it ends up being almost impossible to accurately define the genomic composition of a natural community. This also calls for better and more precise methods of assigning or binning of metagenomic sequences.The Good...Since "all different" is not a very hopeful result, they prepared three replicas of each DNA extraction method so to say which of them showed a lower variability and hence would be more reliable. It turned out that the DNA kit extraction protocol has a larger repeatability, most likely because there's a lower variation in reagent concentrations.And then again, although there's large variability inter- and intra- protocol, there are no radical changes in the relative abundance of each organism. That is, there is no change from the dominance of one organism to another. Although they're still not reflecting the "true" abundances.The Ugly...One of the samples was sequenced twice, one time with classic Sanger capillary sequencing and the other with pyrosequencing. This helped them to show that differences between extraction methods are far greater than differences between sequencing platforms. Still I sensed a bit of anti-pyrosequencing in it. Sure, pyrosequencing gives shorter reads and so a larger amount of reads will be unassignable to reference organisms (at least by BLAST standards). But I'm not sure that these results actually demonstrate that cloning-bias is not so important. It would be necessary to repeat each sample with pyrosequencing to demonstrate this. And it would be also great to replicate the same example as they did with Sanger. This would actually show how much of this variability is really attributable to DNA extraction and how much of it is attributable to cloning bias.The Finale...We desperately need more research like this, that would help us not only to standarize the technology behind metagenomics but also allows to build the robust theoretical framework that metagenomics (and community ecology in general) is so in need. This kind of work should be complemented with in-silico modelations of metagenomes (like that in Mavrommatis et al. 2007), and also with the development of better algorithms to cluster and assign taxonomy to sequenced reads.After all the metagenomic hype, we still do not know the true structure and composition of sequenced microbial communites. But we do know a lot more than before.... Read more »
Morgan, J., Darling, A., & Eisen, J. (2010) Metagenomic Sequencing of an In Vitro-Simulated Microbial Community. PLoS ONE, 5(4). DOI: 10.1371/journal.pone.0010209
Why are large-scale structured databases and meta-analyses important to advance the field of human brain mapping? One reason is that individual functional magnetic resonance imaging (fMRI) studies can be notoriously unreliable and underpowered (Bennett & Miller, 2010; Fliessbach et al., 2010; Kriegeskorte et al., 2009; Vul et al., 2009). At the recent CNS 2010 Annual Meeting, symposium organizer Dr. Tal Yarkoni gave the first talk in a session on the value of a cumulative cognitive neuroscience.---------------Symposium Session 1Sunday, April 18, 10:00 am - 12:00 pm, Westmount et al BallroomTowards a cumulative science of human brain function. . .Talk 1: Motivating a cumulative cognitive neuroscienceTal Yarkoni; Columbia University and University of Colorado at BoulderThousands of functional neuroimaging studies are published every year. Only a small fraction of these studies explicitly attempt a formal synthesis of previous findings. In this talk, I argue for an increased emphasis on cumulative approaches to the study of brain function that aim to synthesize and distill the results of previous studies. Three different motives for such an approach are discussed, including (a) the need to distinguish real findings from false alarms; (b) the desire to organize both cognitive tasks and brain activations into coherent ontologies; and (c) the high likelihood that many fMRI studies are underpowered and consequently produce distorted results. I focus primarily on the last of these points, using simulations and empirical analyses to demonstrate that the results of many individual fMRI studies are likely to appear considerably stronger and more selective than they actually are. I conclude by arguing that these limitations are difficult or impossible to overcome in individual studies, necessitating a stronger focus on consensus building at the disciplinary level.---------------What are the motivations for consensus building? Here are four major reasons:The value of a cumulative scienceMake the literature manageableDistinguish true positives from false positivesDevelop overarching frameworksMinimize the effects of low powerYarkoni's talk focused on the last point. The problem with most individual fMRI studies is a lack of statistical power. Yarkoni (2009) argued that:the primary cause of grossly inflated correlations in whole-brain fMRI analyses is not nonindependence, but the pernicious combination of small sample sizes and stringent alpha-correction levels. Far from defusing Vul et al.'s conclusions [from their notorious 2009 paper], the simulations presented suggest that the level of inflation may be even worse than Vul et al.'s empirical analysis would suggest. Fig. 2 (Yarkoni, 2009). Inflation of significant r values as a function of sample size (x axis) and population effect size (lines). Each point represents the result of 10,000 simulated correlation tests, each conducted at a threshold of p Simply put, small n's result in massively inflated brain-behavior correlations. What can be done about this problem? Include more participants in your studies! And make use of the tools that were described by the subsequent speakers (Van Essen, Wager, Poldrack) for synthesis of mega-databases.For more information, the slides from Tal's talk are available online (PDF).ReferencesBennett CM, Miller MB. (2010). How reliable are the results from functional magnetic resonance imaging? Ann NY Acad Sci. 1191:133-55.Fliessbach K, Rohe T, Linder NS, Trautner P, Elger CE, Weber B. (2010). Retest reliability of reward-related BOLD signals. Neuroimage 50:1168-76.Kriegeskorte N, Simmons WK, Bellgowan PS, Baker CI. (2009). Circular analysis in systems neuroscience: the dangers of double dipping. Nat Neurosci. 12:535-40.Vul E, Harris C, Winkielman P, Pashler H (2009). Puzzlingly High Correlations in fMRI Studies of Emotion, Personality, and Social Cognition. Perspectives on Psychological Science 4:274-290.Yarkoni, T. (2009). Big Correlations in Little Studies: Inflated fMRI Correlations Reflect Low Statistical Power-Commentary on Vul et al. (2009). Perspectives on Psychological Science, 4 (3), 294-298. DOI: 10.1111/j.1745-6924.2009.01127.x
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Yarkoni, T. (2009) Big Correlations in Little Studies: Inflated fMRI Correlations Reflect Low Statistical Power-Commentary on Vul et al. (2009). Perspectives on Psychological Science, 4(3), 294-298. DOI: 10.1111/j.1745-6924.2009.01127.x
Eliminating fishery bycatch isn’t always a good idea
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Zhou, S. et al. (2010) Ecosystem-based fisheries management requires a change to the selective fishing philosophy. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0912771107
Bar-tailed Godwits / Image: Phil Battley Recent studies using satellite telemetry or geolocators have shown that some bird species are capable of very long nonstop flight during migration, far longer than previously thought. Some of the longest belong to Bar-tailed Godwits, which have been tracked performing nonstop flights of over 11,000 km (or about 7,000 miles). Ruddy Turnstones perform similarly impressive flights. A new study in PLoS Biology tries to measure whether there are any limits to nonstop flights.How long a bird is able to fly depends on a few factors. First, it needs to be able to use fuel efficiently. Bar-tailed Godwits do this very well, burning only 0.42% of their body mass per hour of flight. Ruddy Turnstones, Greater Knots, and Blackpoll Warblers have slightly lower efficiency. Flight speed is also important. Bar-tailed Godwits and Blackpoll Warblers have similar fuel efficiency, but a Bar-tailed Godwit can fly twice as far without stopping because it flies more quickly (see graph below). A faster bird will not only fly farther on the same fuel supply but also will be less likely to be blown off course by turbulence.Potential flight range for the bar-tailed godwit (blue curve) and the blackpoll warbler (red curve). Other factors that may influence long-distance flight include body shape and energy consumption. A long-distance migrant must be able to carry sufficient fuel supplies for the flight but do so in a very streamlined body. One way that godwits achieve this is by eliminating unnecessary organ mass and burning muscle mass in the latter stages of a migration flight. Other shorebirds share this trait.A few other species like Sharp-tailed Sandpiper might attempt similar flights, but the Earth imposes its own limit on how far a bird might need to migrate. There are relatively few combinations of wintering grounds and breeding grounds that would require such a long nonstop flight. Some Pectoral Sandpipers breed in Central Asia and winter in South America, but they break up their migration into two stages. Arctic Terns have a longer trip (24,000 km!) but can feed along the way. It seems that the Bar-tailed Godwit's 11,000 km is about as far as a bird is likely to fly without stopping to feed.Hedenström, A. (2010). Extreme Endurance Migration: What Is the Limit to Non-Stop Flight? PLoS Biology, 8 (5) DOI: 10.1371/journal.pbio.1000362Posted on A DC Birding Blog under a Creative Commons 3.0 License.... Read more »
Hedenström, A. (2010) Extreme Endurance Migration: What Is the Limit to Non-Stop Flight?. PLoS Biology, 8(5). DOI: 10.1371/journal.pbio.1000362
The plagues of the Dark Ages are often considered to be one of the worst epidemics humans ever faced. With no sanitary practices, germ theory, or scientific medicine to speak of, the diseases were unstoppable and the patients’ survival depended solely on their luck and the strength of their immune systems. Today, we’re better off [...]... Read more »
Concord Coordinating Committee. (1994) Concorde: MRC/ANRS randomised double-blind controlled trial of immediate and deferred zidovudine in symptom-free HIV infection. The Lancet, 343(8902), 871-881. DOI: 10.1016/S0140-6736(94)90006-X
Prohaska and Gailey (2010) refer to the practice of men who seek 'out women they [those men] perceive as fat or unattractive for sport or sexual gratification’ as 'hogging' (p.13). The big ticket issue, therefore, pivots between men who hate women absolutely and men who love other men for all the wrong reasons. In short, misogyny and homosociality.
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Prohaska, A., & Gailey, J. (2010) Achieving masculinity through sexual predation: the case of hogging. Journal of Gender Studies, 19(1), 13-25. DOI: 10.1080/09589230903525411
Among the great American exports to the rest of the world, there are a bewildering variety of religious cults and sects. Not all have take root, but the most successful - groups like the Mormons, the Jehovah’s Witnesses, and the Seventh Day Adventists - now number in the millions.
Their success is mostly down to prosyletisation, in addition to any endogenous growth (due to fertility) that was the topic of the previous post.
So why are they so successful, and perhaps more importantly where are they successful? Is it something intrinsic to what they offer, or is it more to do with finding fertile soil and a receptive, willing audience? That’s what Ryan Cragun (University of Tampa) and Ronald Lawson (CUNY) set out to discover.
They analysed how these three religious had grown in different countries around the world, to see what kinds of countries saw the most rapid growth, and also whether growth was self limiting.
In turns out that their fastest growth rates are in middle income countries – not at the bottom of the scale, where grinding poverty is most apparent, nor in wealthy countries.
The graphic shows this for the Mormons. The 'Human Development Index' is a standard measure, developed by the UN, which combines life expectancy, adult literacy, and per capita GDP. Mormons grow fastest in countries mid-way along the index.
It’s hard to say why this might be, but it may be linked to the social upheaval that goes hand in hand with modernization. Perhaps people turn to these new, highly active religions to help deal with the stresses and uncertainty that this upheaval can cause.
The other important finding is that growth appears to be self limiting. After an initial burst (the ‘growth momentum’), then growth slows in proportion to the number of people already converted. It’s as if there is a certain pool of people who are attracted to these groups and, once they’re in, recruitment falls away.
What’s intriguing, however, is that there doesn’t seem to be competition between groups. In other words, the growth rate of Mormons is slower if there are already a lot of Mormons in the country, but it’s unaffected by the numbers of Jehovah’s Witnesses.
That suggests that these groups appeal to different kinds of people – although an alternative explanation is simply that the hotspots of each group is separated geographically within a country.
Mormons and Jehovah’s Witnesses have both seen a significant slowdown in growth in recent years, although for Seventh Day Adventists the slowdown is less significant. This is probably because most current Mormons and JWs today live in relatively wealthy countries, where prospects for conversions are poor. In Europe, the number of JWs is actually falling!
Cragun, R., & Lawson, R. (2010). The Secular Transition: The Worldwide Growth of Mormons, Jehovah's Witnesses, and Seventh-day Adventists Sociology of Religion DOI: 10.1093/socrel/srq022
This article by Tom Rees was first published on Epiphenom. It is licensed under Creative Commons.
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Cragun, R., & Lawson, R. (2010) The Secular Transition: The Worldwide Growth of Mormons, Jehovah's Witnesses, and Seventh-day Adventists. Sociology of Religion. DOI: 10.1093/socrel/srq022
Selling patients is sad reality of life as an emergency doctor, will things be worse when the four hour rule is adopted Australia wide?... Read more »
Innes G. (2000) Successful hospitalization of patients with no discernible pathology. CJEM : Canadian journal of emergency medical care , 2(1), 47-51. PMID: 17637127
Mathematical and computational biologists use algorithms to model and understand biological phenomena but as useful as computer systems are to modellers they also represent an example of what biological systems are not: designed. A recent study by researchers in...... Read more »
Yan KK, Fang G, Bhardwaj N, Alexander RP, & Gerstein M. (2010) Comparing genomes to computer operating systems in terms of the topology and evolution of their regulatory control networks. Proceedings of the National Academy of Sciences of the United States of America. PMID: 20439753
Evolution has resulted in a remarkable array of reproductive strategies in the animal kingdom. After all, if one is unsuccessful in passing on one’s genetic blueprints there was really not much point in being alive in the first place. Several invertebrate organisms employ a ‘polyandrous’ sexual system, wherein a female mates with several males. It [...]... Read more »
Huigens, M., Woelke, J., Pashalidou, F., Bukovinszky, T., Smid, H., & Fatouros, N. (2010) Chemical espionage on species-specific butterfly anti-aphrodisiacs by hitchhiking Trichogramma wasps. Behavioral Ecology, 21(3), 470-478. DOI: 10.1093/beheco/arq007
I assume by now that everyone has read A Draft Sequence of the Neandertal Genome. It’s free to all, so you should. At least look at the figures. Also, if you haven’t at least skimmed the supplement, you should do that as well. It’s nearly 200 pages, and basically feels more like a collection of [...]... Read more »
Runners Cramp - Calves cramping - it's AWFUL. In talking with folks who run in VFF's it seems that one usual side effect initially at least is that, when picking up the pace in VFF's (perhaps especially up hill), calves may start to cramp up. Guaranteed, if we keep going with this run, once that cramp starts, the calf or calves will turn to unyielding, painful rock. What can be surprising is ... Read more »
Schwellnus, M. (2008) Cause of Exercise Associated Muscle Cramps (EAMC) -- altered neuromuscular control, dehydration or electrolyte depletion?. British Journal of Sports Medicine, 43(6), 401-408. DOI: 10.1136/bjsm.2008.050401
OHMAN, A. (2005) The role of the amygdala in human fear: Automatic detection of threat. Psychoneuroendocrinology, 30(10), 953-958. DOI: 10.1016/j.psyneuen.2005.03.019
Wagner, T. (2009) Strengthening and Neuromuscular Reeducation of the Gluteus Maximus in a Triathlete With Exercise-Associated Cramping of the Hamstrings. Journal of Orthopaedic and Sports Physical Therapy. DOI: 10.2519/jospt.2010.3110
Caplan N, Rogers R, Parr MK, & Hayes PR. (2009) The effect of proprioceptive neuromuscular facilitation and static stretch training on running mechanics. Journal of strength and conditioning research / National Strength , 23(4), 1175-80. PMID: 19528850
Schwellnus MP. (2007) Muscle cramping in the marathon : aetiology and risk factors. Sports medicine (Auckland, N.Z.), 37(4-5), 364-7. PMID: 17465609
SUBJECTIVE experience poses a major problem for neuroscientists and philosphers alike, and the relationship between them and brain function is particularly puzzling. How can I know that my perception of the colour red is the same as yours, when my experience of the colour occupies a private mental world to which nobody else has access? How is the sensory information from an object transformed into an experience that enters conscious awareness? The neural mechanisms involved are like a black box, whose inner workings are a complete mystery.
In synaesthesia, the information entering one sensory system gives rise to sensations in another sensory modality. Letters can evoke colours, for example, and movements can evoke sounds. The extraordinary experiences of synaesthetes therefore offer a unique opportunity to investigate how the experiences of healthy people are related to brain function. Dutch psychologists now report that different types of synaesthetic experiences are associated with different brain mechanisms, providing a rare glimpse into the workings of the black box.
Read the rest of this post... | Read the comments on this post...... Read more »
Rouw, R., & Scholte, H. (2010) Neural Basis of Individual Differences in Synesthetic Experiences. Journal of Neuroscience, 30(18), 6205-6213. DOI: 10.1523/JNEUROSCI.3444-09.2010
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