Neurofeedback: principles, appraisal and outstanding issues

Neurofeedback is a form of brain training in which subjects are fed back information about some measure of their brain activity which they are instructed to modify in a way thought to be functionally advantageous. Over the last twenty years, NF has been used to treat various neurological and psychiatric conditions, and to improve cognitive function in various contexts. However, despite its growing popularity, each of the main steps in NF comes with its own set of often covert assumptions. Here we critically examine some conceptual and methodological issues associated with the way general objectives and neural targets of NF are defined, and review the neural mechanisms through which NF may act, and the way its efficacy is gauged. The NF process is characterised in terms of functional dynamics, and possible ways in which it may be controlled are discussed. Finally, it is proposed that improving NF will require better understanding of various fundamental aspects of brain dynamics and a more precise definition of functional brain activity and brain-behaviour relationships.Comment: 12 page

Neurofeedback and neuromodulation techniques and applications

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Multiway Array Decomposition Analysis of EEGs in Alzheimer’s Disease

Methods for the extraction of features from physiological datasets are growing needs as clinical investigations of Alzheimer’s disease (AD) in large and heterogeneous population increase. General tools allowing diagnostic regardless of recording sites, such as different hospitals, are essential and if combined to inexpensive non-invasive methods could critically improve mass screening of subjects with AD. In this study, we applied three state of the art multiway array decomposition (MAD) methods to extract features from electroencephalograms (EEGs) of AD patients obtained from multiple sites. In comparison to MAD, spectral-spatial average filter (SSFs) of control and AD subjects were used as well as a common blind source separation method, algorithm for multiple unknown signal extraction (AMUSE). We trained a feed-forward multilayer perceptron (MLP) to validate and optimize AD classification from two independent databases. Using a third EEG dataset, we demonstrated that features extracted from MAD outperformed features obtained from SSFs AMUSE in terms of root mean squared error (RMSE) and reaching up to 100% of accuracy in test condition. We propose that MAD maybe a useful tool to extract features for AD diagnosis offering great generalization across multi-site databases and opening doors to the discovery of new characterization of the disease

On the verge of Umdeutung in Minnesota: Van Vleck and the correspondence principle (Part One)

In October 1924, the Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Van Vleck combined advanced techniques of classical mechanics with Bohr's correspondence principle and Einstein's quantum theory of radiation to find quantum analogues of classical expressions for the emission, absorption, and dispersion of radiation. For modern readers Van Vleck's paper is much easier to follow than the famous paper by Kramers and Heisenberg on dispersion theory, which covers similar terrain and is widely credited to have led directly to Heisenberg's "Umdeutung" paper. This makes Van Vleck's paper extremely valuable for the reconstruction of the genesis of matrix mechanics. It also makes it tempting to ask why Van Vleck did not take the next step and develop matrix mechanics himself.Comment: 82 page

Crash characteristics and patterns of injury among hospitalized motorised two-wheeled vehicle users in urban India

<p>Abstract</p> <p>Background</p> <p>Traffic crashes and consequent injuries represent a growing public health concern in India, particularly in light of increasing motorization. Motorised two-wheeled vehicles (MTV) constitute a large portion of the vehicle fleet in India. We report the crash characteristics and injury patterns among a cohort of MTV riders and pillions presenting to hospital post-crash.</p> <p>Methods</p> <p>Consecutive MTV riders and pillions, whether alive or dead, injured in a road traffic crash presenting to the emergency departments of two government hospitals and three branches of a private hospital in urban Hyderabad, India, were recruited to this study.</p> <p>Results</p> <p>378 MTV users were enrolled to the study of whom 333 (88.1%) were male, 252 (66.7%) were riders and median age was 31.3 years. A total of 223 (59%) MTV users were injured in multi-vehicle crashes while one-third had a frontal impact. The majority (77%) were assessed as having a Glasgow coma score (GCS) of 13–15, 12% a GCS of 9–12 and 11% a GCS of 3–8. No difference was seen in the severity distribution of injuries based on GCS among riders and pillions. Open wounds and superficial injuries to the head (69.3%) and upper extremity (27%) and lower extremity (24%) were the most common injuries. 43 (11%) sustained an intracranial injury, including 12 (28%) with associated fracture of the bones of the head. There were few differences in types of injuries sustained by riders and pillions though riders had a significantly lower risk of crush injuries of the lower extremity than pillions (relative risk, RR 0.25, 95% CI 0.08–0.81) and female pillions were at a significantly lower risk of sustaining fractures of the lower extremity than male pillions (RR 0.30, 95% CI 0.09 – 0.94). Overall, 42 (11%) MTV users died, of which 42.8% died before reaching the hospital. Only 74 (19.6%) MTV users had worn a helmet correctly and failure to wear a helmet was associated with a five times greater risk of intracranial injury (RR 4.99, 95% CI 1.23–20.1). Of the 19 pre-hospital deaths, 16 (84%) had not worn a helmet.</p> <p>Conclusion</p> <p>Head injuries accounted for the major proportion of injuries sustained in MTV users. Non-helmet use was associated with increased risk of serious head injuries. The data presented on the nature and severity of injuries sustained by MTV users can assist with planning to deal with these consequences as well as prevention of these injuries given the high use of MTV in India.</p

Contrast-Enhanced Endoscopic Ultrasound for Identification of Sentinel Lymph Nodes in Esophageal Cancer

Introduction: In esophageal carcinoma, lymph node involvement is a crucial aspect of nodal staging and determining treatment strategies. Although grayscale endoscopic ultrasound (EUS) is the standard of care for staging, it is unable to identify lymph node drainage from primary tumors or sentinel lymph nodes (SLN). The goal of this study was to determine if Contrast Enhanced Endoscopic Ultrasound (CE- EUS) is superior to EUS in the identification of SLNs and nodal staging in esophageal carcinoma. Methods: In the unblinded pilot study, patients with newly diagnosed esophageal carcinoma were recruited to undergo CE-EUS and standard EUS. EUS was performed and visible lymph nodes were noted. The contrast agent, Sonazoid was injected peri-tumorally. Fine needle aspiration (FNA) was performed on all lymph nodes considered suspicious by either modality. Specimens were compared, using cytology as a reference. Results: 55 peri-esophageal lymph nodes were collected from 14 enrolled patients, with tumor staging of T2 and T3. 10 nodes identified as suspicious by EUS and 19 nodes identified as suspicious by CE-EUS were sampled by FNA. 4 nodes (40% cytologic yield) identified by EUS and 12 nodes (63% cytologic yield) identified by CE-EUS showed signs of metastatic disease. Nodal staging was upgraded in 4 patients (29%) with the addition of SLNs identified by CE-EUS. Discussion: CE-EUS may increase the identification of SLNs and increase cytologic yield that would not have normally been biopsied using EUS. This increase in SLN identification and cytologic yield can provide more accurate lymph node staging in esophageal carcinoma. Further study is indicated

Mathematical images in advertising: constructing difference and shaping identity, in global consumer culture

Mathematics educators have long emphasised the importance of attitudes and feelings towards mathematics, as crucial in motivating (or not) its learning and use, and as influenced in turn by its social images. This paper is about images of mathematics. Our search for advertisements containing such images of in UK daily newspapers, during 2006-2008, found that 4.7% of editions included a ‘mathematical’ advert, compared with 1.7% in pilot work for 1994-2003. The incidence varied across type of newspaper, being correlated with class and gender profiles of the readership. Three-quarters of advertisements were classified as containing only very simple mathematics. ‘Semiotic-discursive’ analysis of selected advertisements suggests that they draw on mathematics not to inform, but to connote qualities like precision, certainty and authority. We discuss the discourse on mathematics in advertising as ‘quasi-pedagogic’ discourse, and argue that its oversimplified forms, being empty of mathematical content, become powerful means for regulating and ‘pedagogising’ today’s global consumers