Multisensory causal inference in the brain

At any given moment, our brain processes multiple inputs from its different sensory modalities (vision, hearing, touch, etc.). In deciphering this array of sensory information, the brain has to solve two problems: (1) which of the inputs originate from the same object and should be integrated and (2) for the sensations originating from the same object, how best to integrate them. Recent behavioural studies suggest that the human brain solves these problems using optimal probabilistic inference, known as Bayesian causal inference. However, how and where the underlying computations are carried out in the brain have remained unknown. By combining neuroimaging-based decoding techniques and computational modelling of behavioural data, a new study now sheds light on how multisensory causal inference maps onto specific brain areas. The results suggest that the complexity of neural computations increases along the visual hierarchy and link specific components of the causal inference process with specific visual and parietal regions

Palaeomagnetic, geochronological and geochemical study of Mesoproterozoic Lakhna Dykes in the Bastar Craton, India: Implications for the Mesoproterozoic supercontinent

Palaeomagnetic analysis of the Lakhna Dykes (Bastar Craton, India) yields a palaeopole at 36.6°N, 132.8°E, dp=12.4°, dm=15.9°, and the U--Pb zircon age obtained from one of the rhyolitic dykes is 1466.4±2.6 Ma (MSWD=0.21, concordia age based on two analyses with identical Pb--U ages), similar to previously published U\Pb ages. Major and trace element analyses of the Lakhna Dykes show shoshonitic and high-K calc-alkaline affinities consistent with a subduction related characteristics suggesting an active continental margin setting. This is in keeping with the Palaeo- to Mesoproterozoic tectonic environments in the eastern Indian margin. The new 1460 Ma Indian palaeopole was used to test possible palaeopositions of India within the Mesoproterozoic supercontinent Columbia. Of the four palaeomagnetically permissible reconstructions, juxtaposing western India against south-west Baltica is geologically the most reliably constrained and best fitting model. Our preferred reconstruction implies a long Palaeo- to Mesoproterozoic accretionary orogen stretching from south-eastern Laurentia through south-western Baltica to south-eastern India. Breakup of India and Baltica probably occurred in the Late Mesoproterozoic, but additional constraints are needed

The clinical features of the piriformis syndrome: a systematic review

Piriformis syndrome, sciatica caused by compression of the sciatic nerve by the piriformis muscle, has been described for over 70 years; yet, it remains controversial. The literature consists mainly of case series and narrative reviews. The objectives of the study were: first, to make the best use of existing evidence to estimate the frequencies of clinical features in patients reported to have PS; second, to identify future research questions. A systematic review was conducted of any study type that reported extractable data relevant to diagnosis. The search included all studies up to 1 March 2008 in four databases: AMED, CINAHL, Embase and Medline. Screening, data extraction and analysis were all performed independently by two reviewers. A total of 55 studies were included: 51 individual and 3 aggregated data studies, and 1 combined study. The most common features found were: buttock pain, external tenderness over the greater sciatic notch, aggravation of the pain through sitting and augmentation of the pain with manoeuvres that increase piriformis muscle tension. Future research could start with comparing the frequencies of these features in sciatica patients with and without disc herniation or spinal stenosis

Ribonuclease 1 attenuates septic cardiomyopathy and cardiac apoptosis in a murine model of polymicrobial sepsis.

Septic cardiomyopathy is a life-threatening organ dysfunction caused by sepsis. Ribonuclease 1 (RNase 1) belongs to a group of host-defense peptides that specifically cleave extracellular RNA (eRNA). The activity of RNase1 is inhibited by ribonuclease-inhibitor 1 (RNH1). The role of RNase 1 in septic cardiomyopathy and associated cardiac apoptosis, however, is completely unknown. Here, we showed that sepsis resulted in a significant increase in RNH1 and eRNA serum levels compared to those of healthy subjects (p < 0.05). Treatment with RNase 1 resulted in a significant decrease of apoptosis, induced by the intrinsic pathway, and TNF expression in murine cardiomyocytes exposed to either necrotic cardiomyocytes or serum of septic patients for 16 h (p < 0.05). Furthermore, treatment of septic mice with RNase 1 resulted in a reduction in cardiac apoptosis, TNF expression and septic cardiomyopathy (p < 0.05). These data demonstrate that eRNA plays a crucial role in the pathophysiology of the organ (cardiac) dysfunction in sepsis and RNase and RNH1 may be new therapeutic targets/strategies to reduce the cardiac injury and dysfunction caused by sepsis

Complementary and alternative medicine use among US Navy and Marine Corps personnel

<p>Abstract</p> <p>Background</p> <p>Recently, numerous studies have revealed an increase in complementary and alternative medicine (CAM) use in US civilian populations. In contrast, few studies have examined CAM use within military populations, which have ready access to conventional medicine. Currently, the prevalence and impact of CAM use in US military populations remains unknown.</p> <p>Methods</p> <p>To investigate CAM use in US Navy and Marine Corps personnel, the authors surveyed a stratified random sample of 5,000 active duty and Reserve/National Guard members between December 2000 and July 2002. Chi-square tests and multivariable logistic regression were used to assess univariate associations and adjusted odds of CAM use in this population.</p> <p>Results and discussion</p> <p>Of 3,683 service members contacted, 1,446 (39.3%) returned a questionnaire and 1,305 gave complete demographic and survey data suitable for study. Among respondents, more than 37% reported using at least one CAM therapy during the past year. Herbal therapies were among the most commonly reported (15.9%). Most respondents (69.8%) reported their health as being very good or excellent. Modeling revealed that CAM use was most common among personnel who were women, white, and officers. Higher levels of recent physical pain and lower levels of satisfaction with conventional medical care were significantly associated with increased odds of reporting CAM use.</p> <p>Conclusion</p> <p>These data suggest that CAM use is prevalent in the US military and consistent with patterns in other US civilian populations. Because there is much to be learned about CAM use along with allopathic therapy, US military medical professionals should record CAM therapies when collecting medical history data.</p

A Platform for Processing Expression of Short Time Series (PESTS)

<p>Abstract</p> <p>Background</p> <p>Time course microarray profiles examine the expression of genes over a time domain. They are necessary in order to determine the complete set of genes that are dynamically expressed under given conditions, and to determine the interaction between these genes. Because of cost and resource issues, most time series datasets contain less than 9 points and there are few tools available geared towards the analysis of this type of data.</p> <p>Results</p> <p>To this end, we introduce a platform for Processing Expression of Short Time Series (PESTS). It was designed with a focus on usability and interpretability of analyses for the researcher. As such, it implements several standard techniques for comparability as well as visualization functions. However, it is designed specifically for the unique methods we have developed for significance analysis, multiple test correction and clustering of short time series data. The central tenet of these methods is the use of biologically relevant features for analysis. Features summarize short gene expression profiles, inherently incorporate dependence across time, and allow for both full description of the examined curve and missing data points.</p> <p>Conclusions</p> <p>PESTS is fully generalizable to other types of time series analyses. PESTS implements novel methods as well as several standard techniques for comparability and visualization functions. These features and functionality make PESTS a valuable resource for a researcher's toolkit. PESTS is available to download for free to academic and non-profit users at <url>http://www.mailman.columbia.edu/academic-departments/biostatistics/research-service/software-development</url>.</p

Coverage, Continuity and Visual Cortical Architecture

The primary visual cortex of many mammals contains a continuous representation of visual space, with a roughly repetitive aperiodic map of orientation preferences superimposed. It was recently found that orientation preference maps (OPMs) obey statistical laws which are apparently invariant among species widely separated in eutherian evolution. Here, we examine whether one of the most prominent models for the optimization of cortical maps, the elastic net (EN) model, can reproduce this common design. The EN model generates representations which optimally trade of stimulus space coverage and map continuity. While this model has been used in numerous studies, no analytical results about the precise layout of the predicted OPMs have been obtained so far. We present a mathematical approach to analytically calculate the cortical representations predicted by the EN model for the joint mapping of stimulus position and orientation. We find that in all previously studied regimes, predicted OPM layouts are perfectly periodic. An unbiased search through the EN parameter space identifies a novel regime of aperiodic OPMs with pinwheel densities lower than found in experiments. In an extreme limit, aperiodic OPMs quantitatively resembling experimental observations emerge. Stabilization of these layouts results from strong nonlocal interactions rather than from a coverage-continuity-compromise. Our results demonstrate that optimization models for stimulus representations dominated by nonlocal suppressive interactions are in principle capable of correctly predicting the common OPM design. They question that visual cortical feature representations can be explained by a coverage-continuity-compromise.Comment: 100 pages, including an Appendix, 21 + 7 figure

Coordinated optimization of visual cortical maps (II) Numerical studies

It is an attractive hypothesis that the spatial structure of visual cortical architecture can be explained by the coordinated optimization of multiple visual cortical maps representing orientation preference (OP), ocular dominance (OD), spatial frequency, or direction preference. In part (I) of this study we defined a class of analytically tractable coordinated optimization models and solved representative examples in which a spatially complex organization of the orientation preference map is induced by inter-map interactions. We found that attractor solutions near symmetry breaking threshold predict a highly ordered map layout and require a substantial OD bias for OP pinwheel stabilization. Here we examine in numerical simulations whether such models exhibit biologically more realistic spatially irregular solutions at a finite distance from threshold and when transients towards attractor states are considered. We also examine whether model behavior qualitatively changes when the spatial periodicities of the two maps are detuned and when considering more than 2 feature dimensions. Our numerical results support the view that neither minimal energy states nor intermediate transient states of our coordinated optimization models successfully explain the spatially irregular architecture of the visual cortex. We discuss several alternative scenarios and additional factors that may improve the agreement between model solutions and biological observations.Comment: 55 pages, 11 figures. arXiv admin note: substantial text overlap with arXiv:1102.335

Efficient Coding and Statistically Optimal Weighting of Covariance among Acoustic Attributes in Novel Sounds

To the extent that sensorineural systems are efficient, redundancy should be extracted to optimize transmission of information, but perceptual evidence for this has been limited. Stilp and colleagues recently reported efficient coding of robust correlation (r = .97) among complex acoustic attributes (attack/decay, spectral shape) in novel sounds. Discrimination of sounds orthogonal to the correlation was initially inferior but later comparable to that of sounds obeying the correlation. These effects were attenuated for less-correlated stimuli (r = .54) for reasons that are unclear. Here, statistical properties of correlation among acoustic attributes essential for perceptual organization are investigated. Overall, simple strength of the principal correlation is inadequate to predict listener performance. Initial superiority of discrimination for statistically consistent sound pairs was relatively insensitive to decreased physical acoustic/psychoacoustic range of evidence supporting the correlation, and to more frequent presentations of the same orthogonal test pairs. However, increased range supporting an orthogonal dimension has substantial effects upon perceptual organization. Connectionist simulations and Eigenvalues from closed-form calculations of principal components analysis (PCA) reveal that perceptual organization is near-optimally weighted to shared versus unshared covariance in experienced sound distributions. Implications of reduced perceptual dimensionality for speech perception and plausible neural substrates are discussed

The use of CAM and conventional treatments among primary care consulters with chronic musculoskeletal pain

Chronic musculoskeletal pain is the single most cited reason for use of complementary and alternative medicine (CAM). Primary care is the most frequent conventional medical service used by patients with pain in the UK. We are unaware, however, of a direct evidence of the extent of CAM use by primary care patients, and how successful they perceive it to be. Methods Aims and objectives To determine CAM use among patients with chronic musculoskeletal pain who have consulted about their pain in primary care. Study design Face-to-face interview-based survey. Setting Three general practices in North Staffordshire. Participants Respondents to a population pain survey who had reported having musculoskeletal pain in the survey and who had consulted about their pain in primary care in the previous 12 months as well as consenting to further research and agreeing to an interview. Information was gathered about their pain and the use of all treatments for pain, including CAM, in the previous year. Results 138 interviews were completed. 116 participants (84%) had used at least one CAM treatment for pain in the previous year. 65% were current users of CAM. The ratio of over-the-counter CAM use to care from a CAM provider was 3:2. 111 participants (80%) had used conventional treatment. 95 (69%) were using a combination of CAM and conventional treatment. Glucosamine and fish oil were the most commonly used CAM treatments (38%, 35% respectively). Most CAM treatments were scored on average as being helpful, and users indicated that they intended to use again 87% of the CAM treatments they had already used. Conclusion We provide direct evidence that most primary care consulters with chronic musculoskeletal pain have used CAM in the previous year, usually in combination with conventional treatments. The high prevalence and wide range of users experiences of benefit and harm from CAM strengthen the argument for more research into this type of medicine to quantify benefit and assess safety. The observation that most users of conventional medicine also used CAM suggests a continuing need for more investigation of effective pain management in primary care