The sensory feedback mechanisms enabling couples to walk synchronously: An initial investigation

The inattentive eye often will not notice it, but synchronization among human walking partners is quite common. In this first investigation of this phenomenon, we studied its frequency and the mechanisms that contribute to this form of "entrainment." Specifically, by modifying the available communication links between two walking partners, we isolated the feedback mechanisms that enable couples to synchronize their stepping pattern when they walk side-by-side. Although subjects were unaware of the research aims and were not specifically asked to walk in synchrony, we observed synchronized walking in almost 50% of the walking trials, among couples who do not usually walk together. The strongest in-phase synchrony occurred in the presence of tactile feedback (i.e., handholding), perhaps because of lower and upper extremity coupling driven in part by arm swing. Interestingly, however, even in the absence of visual or auditory communication, couples also frequently walked in synchrony while 180 degrees out-of-phase, likely using different feedback mechanisms. These findings may partially explain how patients with certain gait disorders and disturbed rhythm enhance their gait when they walk with a partner and suggest alternative interventions that might improve the stepping pattern. Further, this preliminary investigation highlights the relatively ubiquitous nature of an interesting phenomenon that has not previously been studied and suggests that further work is needed to better understand the mechanisms that entrain the gait of two walking partners and allows couples to walk in synchrony with minimal or no conscious effort

Early neuromodulation prevents the development of brain and behavioral abnormalities in a rodent model of schizophrenia

The notion that schizophrenia is a neurodevelopmental disorder in which neuropathologies evolve gradually over the developmental course indicates a potential therapeutic window during which pathophysiological processes may be modified to halt disease progression or reduce its severity. Here we used a neurodevelopmental maternal immune stimulation (MIS) rat model of schizophrenia to test whether early targeted modulatory intervention would affect schizophrenia’s neurodevelopmental course. We applied deep brain stimulation (DBS) or sham stimulation to the medial prefrontal cortex (mPFC) of adolescent MIS rats and respective controls, and investigated its behavioral, biochemical, brain-structural and -metabolic effects in adulthood. We found that mPFC-DBS successfully prevented the emergence of deficits in sensorimotor gating, attentional selectivity and executive function in adulthood, as well as the enlargement of lateral ventricle volumes and mal-development of dopaminergic and serotonergic transmission. These data suggest that the mPFC may be a valuable target for effective preventive treatments. This may have significant translational value, suggesting that targeting the mPFC before the onset of psychosis via less invasive neuromodulation approaches may be a viable preventive strategy.We thank Renate Winter, Doris Zschaber and Roselies Pickert for excellent technical assistance. This research was conducted under the EraNet Neuron framework (DBS_F20rat) and supported by the BMBF, Germany (B01EW1103, 01EE1403A), Fundación Mapfre, Comunidad de Madrid and the Ministry of Economy and Competitiveness ISCIII-FIS grants (PI14/00860, CPII/00005) co-financed by ERDF (FEDER) Funds from the European Commission, ‘A way of making Europe’, Spain (PI14/00860, CPII/00005, MV1500002), the CSO-MOH, Israel (3-8580) and the Canadian Institutes of Health Research, Canada (CIHR, 110068), and co-financed by the DFG, Germany (WI 2140/1-1/2; WI 2140/2-1).Publicad

Human neural stem cells enhance structural plasticity and axonal transport in the ischaemic brain

Stem cell transplantation promises new hope for the treatment of stroke although significant questions remain about how the grafted cells elicit their effects. One hypothesis is that transplanted stem cells enhance endogenous repair mechanisms activated after cerebral ischaemia. Recognizing that bilateral reorganization of surviving circuits is associated with recovery after stroke, we investigated the ability of transplanted human neural progenitor cells to enhance this structural plasticity. Our results show the first evidence that human neural progenitor cell treatment can significantly increase dendritic plasticity in both the ipsi- and contralesional cortex and this coincides with stem cell-induced functional recovery. Moreover, stem cell-grafted rats demonstrated increased corticocortical, corticostriatal, corticothalamic and corticospinal axonal rewiring from the contralesional side; with the transcallosal and corticospinal axonal sprouting correlating with functional recovery. Furthermore, we demonstrate that axonal transport, which is critical for both proper axonal function and axonal sprouting, is inhibited by stroke and that this is rescued by the stem cell treatment, thus identifying another novel potential mechanism of action of transplanted cells. Finally, we established in vitro co-culture assays in which these stem cells mimicked the effects observed in vivo. Through immunodepletion studies, we identified vascular endothelial growth factor, thrombospondins 1 and 2, and slit as mediators partially responsible for stem cell-induced effects on dendritic sprouting, axonal plasticity and axonal transport in vitro. Thus, we postulate that human neural progenitor cells aid recovery after stroke through secretion of factors that enhance brain repair and plasticity

Endoscopic sinus surgery for maxillary sinus mucoceles

BACKGROUND: Maxillary sinus mucoceles are relatively rare among all paranasal sinus mucoceles. With the introduction of endoscopic sinus surgical techniques, rhinologic surgeons prefer transnasal endoscopic management of sinus mucoceles. The aim of this study is to describe the clinical presentation of maxillary sinus mucoceles and to establish the efficacy of endoscopic management of sinus mucoceles. METHODS: Between 2003 and 2005, 14 patients underwent endoscopic sinus surgery for maxillary sinus mucocele. The presenting sign and symptoms, radiological findings, surgical management and need for revision surgery were reviewed. RESULTS: There were eight males and six females with an age range of 14 to 65. Ten patients complained of nasal obstruction, five of nasal drainage, five of cheek pressure or pain and one of proptosis of the eye and cheek swelling. The maxillary sinus and ipsilateral ethmoid sinus involvement on computed tomographic studies was seen in 4 patients. Four patients had history of endoscopic ethmoidectomy surgery for ethmoid sinusitis and one had Caldwell-Luc operation in the past. Ethmoidectomy with middle meatal antrostomy and marsupialization of the mucocele was performed in all patients. Postoperative follow-up ranged between 8 to 48 months. All patients had a patent middle meatal antrostomy and healthy maxillary sinus mucosa. No patients need revision surgery. CONCLUSION: The most common causes of mucoceles are chronic infection, allergic sinonasal disease, trauma and previous surgery. In 64% of the patients of our study cause remains uncertain. Endoscopic sinus surgery is an effective treatment for maxillary sinus mucoceles with a favorable long-term outcome

Charge Fractionalization in nonchiral Luttinger systems

One-dimensional metals, such as quantum wires or carbon nanotubes, can carry charge in arbitrary units, smaller or larger than a single electron charge. However, according to Luttinger theory, which describes the low-energy excitations of such systems, when a single electron is injected by tunneling into the middle of such a wire, it will tend to break up into separate charge pulses, moving in opposite directions, which carry definite fractions $f$ and $(1-f)$ of the electron charge, determined by a parameter $g$ that measures the strength of charge interactions in the wire. (The injected electron will also produce a spin excitation, which will travel at a different velocity than the charge excitations.) Observing charge fractionalization physics in an experiment is a challenge in those (nonchiral) low-dimensional systems which are adiabatically coupled to Fermi liquid leads. We theoretically discuss a first important step towards the observation of charge fractionalization in quantum wires based on momentum-resolved tunneling and multi-terminal geometries, and explain the recent experimental results of H. Steinberg {\it et al.}, Nature Physics {\bf 4}, 116 (2008).Comment: 31 pages, final version to appear in Annals of Physic

Self-force: Computational Strategies

Building on substantial foundational progress in understanding the effect of a small body's self-field on its own motion, the past 15 years has seen the emergence of several strategies for explicitly computing self-field corrections to the equations of motion of a small, point-like charge. These approaches broadly fall into three categories: (i) mode-sum regularization, (ii) effective source approaches and (iii) worldline convolution methods. This paper reviews the various approaches and gives details of how each one is implemented in practice, highlighting some of the key features in each case.Comment: Synchronized with final published version. Review to appear in "Equations of Motion in Relativistic Gravity", published as part of the Springer "Fundamental Theories of Physics" series. D. Puetzfeld et al. (eds.), Equations of Motion in Relativistic Gravity, Fundamental Theories of Physics 179, Springer, 201

EZH2 promotes a bi-lineage identity in basal-like breast cancer cells

The mechanisms regulating breast cancer differentiation state are poorly understood. Of particular interest are molecular regulators controlling the highly aggressive and poorly differentiated traits of basal-like breast carcinomas. Here we show that the Polycomb factor EZH2 maintains the differentiation state of basal-like breast cancer cells, and promotes the expression of progenitor-associated and basal-lineage genes. Specifically, EZH2 regulates the composition of basal-like breast cancer cell populations by promoting a ‘bi-lineage’ differentiation state, in which cells co-express basal- and luminal-lineage markers. We show that human basal-like breast cancers contain a subpopulation of bi-lineage cells, and that EZH2-deficient cells give rise to tumors with a decreased proportion of such cells. Bi-lineage cells express genes that are active in normal luminal progenitors, and possess increased colony-formation capacity, consistent with a primitive differentiation state. We found that GATA3, a driver of luminal differentiation, performs a function opposite to EZH2, acting to suppress bi-lineage identity and luminal-progenitor gene expression. GATA3 levels increase upon EZH2 silencing, mediating a decrease in bi-lineage cell numbers. Our findings reveal a novel role for EZH2 in controlling basal-like breast cancer differentiation state and intra-tumoral cell composition

Multiclass classification of microarray data samples with a reduced number of genes

<p>Abstract</p> <p>Background</p> <p>Multiclass classification of microarray data samples with a reduced number of genes is a rich and challenging problem in Bioinformatics research. The problem gets harder as the number of classes is increased. In addition, the performance of most classifiers is tightly linked to the effectiveness of mandatory gene selection methods. Critical to gene selection is the availability of estimates about the maximum number of genes that can be handled by any classification algorithm. Lack of such estimates may lead to either computationally demanding explorations of a search space with thousands of dimensions or classification models based on gene sets of unrestricted size. In the former case, unbiased but possibly overfitted classification models may arise. In the latter case, biased classification models unable to support statistically significant findings may be obtained.</p> <p>Results</p> <p>A novel bound on the maximum number of genes that can be handled by binary classifiers in binary mediated multiclass classification algorithms of microarray data samples is presented. The bound suggests that high-dimensional binary output domains might favor the existence of accurate and sparse binary mediated multiclass classifiers for microarray data samples.</p> <p>Conclusions</p> <p>A comprehensive experimental work shows that the bound is indeed useful to induce accurate and sparse multiclass classifiers for microarray data samples.</p