Time, touch and temperature affect perceived finger position and ownership in the grasp illusion

Abstract

Perceived body position and ownership are fundamental to our ability to sense and interact with the world. Previous work indicates that temporally congruent, repetitive multisensory stimuli are needed to alter the sense of body ownership. In the present study 30 subjects passively grasped an artificial rubber finger with their left index and thumb while their right index finger, located 12 cm below, was lightly clamped. Fingers with varied physical characteristics were also passively grasped to determine how these characteristics influenced perceived body position and ownership. Subjects immediately felt their hands to be 5.3 cm [3.4 to 7.3] (mean [95%CI]) closer, a feeling that remained after 3 min (6.0 cm [4.5 to 7.5]). By the end of the trial, perceived ownership increased by 1.2 [0.6 to 1.9] points on a 7-point Likert scale, with the group average moving from 'neither agree or disagree' at the start to 'somewhat agree' at the end. Compared to grasping a control rubber finger, grasping a cold, rough, oddly shaped or rectangular shaped finger-like object reduced perceived ownership. These results provide new insights into the role of cutaneous sensory receptors in defining these aspects of proprioception, and the speed with which these effects occur. Static touch rapidly induces large, sustained changes in perceived body position and prolonged exposure to these cutaneous inputs, alone, can induce a sense of body ownership. Also, certain physical characteristics of grasped objects influence the sense of body ownership.

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2. Do repeated limbic seizures induce depression-like behavior in rats?

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): W. McIntyre Burnham, Brian W. Scott
It has been reported that rapid kindling of the hippocampus produces lasting depression-like behavior in rats, as evidenced by increased immobility in the forced swim test and a loss of preference for sweetened water (Mazarati et al., 2007). This might suggest that repeated limbic seizure activity could be the cause of the depression often seen in patients with temporal lobe epilepsy.Sixty-day old male Wistar rats were implanted with electrodes in the amygdala and ventral hippocampus and kindled (or sham kindled) daily to a criterion of 10 stage 5 seizures. Two weeks later subjects were tested in the forced swim and sweet taste preference tests. No differences were found between the kindled and sham kindled animals.Subsequently, twenty-one day old male Wistar rat pups were implanted and quick kindled (or sham kindled) in the ventral hippocampus. Kindling was accomplished in a single day by stimulating every 5min for 84 stimulations. Four days or two weeks later they were tested in the forced swim and sweet taste preference tests. No differences were found between the kindled and sham kindled animals.The present data do not support the idea that repeated limbic seizures induce depression-like behavior in rats.



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Machine-based classification of ADHD and nonADHD participants using time/frequency features of event-related neuroelectric activity

Publication date: December 2017
Source:Clinical Neurophysiology, Volume 128, Issue 12
Author(s): Hüseyin Öztoprak, Mehmet Toycan, Yaşar Kemal Alp, Orhan Arıkan, Elvin Doğutepe, Sirel Karakaş
ObjectiveAttention-deficit/hyperactivity disorder (ADHD) is the most frequent diagnosis among children who are referred to psychiatry departments. Although ADHD was discovered at the beginning of the 20th century, its diagnosis is still confronted with many problems.MethodA novel classification approach that discriminates ADHD and nonADHD groups over the time-frequency domain features of event-related potential (ERP) recordings that are taken during Stroop task is presented. Time-Frequency Hermite-Atomizer (TFHA) technique is used for the extraction of high resolution time-frequency domain features that are highly localized in time-frequency domain. Based on an extensive investigation, Support Vector Machine-Recursive Feature Elimination (SVM-RFE) was used to obtain the best discriminating features.ResultsWhen the best three features were used, the classification accuracy for the training dataset reached 98%, and the use of five features further improved the accuracy to 99.5%. The accuracy was 100% for the testing dataset. Based on extensive experiments, the delta band emerged as the most contributing frequency band and statistical parameters emerged as the most contributing feature group.ConclusionThe classification performance of this study suggests that TFHA can be employed as an auxiliary component of the diagnostic and prognostic procedures for ADHD.SignificanceThe features obtained in this study can potentially contribute to the neuroelectrical understanding and clinical diagnosis of ADHD.



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Interindividual variability in response to continuous theta-burst stimulation in healthy adults

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Ali Jannati, Gabrielle Block, Lindsay M. Oberman, Alexander Rotenberg, Alvaro Pascual-Leone
ObjectiveWe used complete-linkage cluster analysis to identify healthy subpopulations with distinct responses to continuous theta-burst stimulation (cTBS).Methods21 healthy adults (age±SD, 36.9±15.2years) underwent cTBS of left motor cortex. Natural log-transformed motor evoked potentials (LnMEPs) at 5–50min post-cTBS (T5–T50) were calculated.ResultsTwo clusters were found; Group 1 (n=12) that showed significant MEP facilitation at T15, T20, and T50 (p's<0.006), and Group 2 (n=9) that showed significant suppression at T5–T15 (p's<0.022). LnMEPs at T10 and T40 were best predictors of, and together accounted for 80% of, cluster assignment.In an exploratory analysis, we examined the roles of brain-derived neurotrophic factor (BDNF) and apolipoprotein E (APOE) polymorphisms in the cTBS response. Val66Met participants showed greater facilitation at T10 than Val66Val participants (p=0.025). BDNF and cTBS intensity predicted 59% of interindividual variability in LnMEP at T10. APOE did not significantly affect LnMEPs at any time point (p's>0.32).ConclusionsData-driven cluster analysis can identify healthy subpopulations with distinct cTBS responses. T10 and T40 LnMEPs were best predictors of cluster assignment. T10 LnMEP was influenced by BDNF polymorphism and cTBS intensity.SignificanceHealthy adults can be sorted into subpopulations with distinct cTBS responses that are influenced by genetics.



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Effect of local cooling on excitation-contraction coupling in myasthenic muscle: Another mechanism of ice-pack test in myasthenia gravis

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Daisuke Yamamoto, Tomihiro Imai, Emiko Tsuda, Takayoshi Hozuki, Rika Yamauchi, Shin Hisahara, Jun Kawamata, Shun Shimohama
ObjectiveThe ice-pack test is a convenient diagnostic testing procedure for myasthenia gravis (MG). We investigated the underlying mechanism of the ice-pack test performed on bilateral masseters.MethodsWe performed trigeminal repetitive nerve stimulation (RNS), excitation-contraction (E-C) coupling assessment (Imai's method) and bite force measurement before and after cooling of the masseters in MG patients and normal controls. After placing the ice-pack on the masseters for 3min, serial recordings of the three tests were performed at various time intervals during 10min after cooling.ResultsThe bite force increased significantly after cooling in ice-pack-positive MG patients. The acceleration and acceleration ratio (acceleration at a given time to baseline acceleration) of jaw movement increased significantly after cooling of the masseters in ice-pack-positive MG patients compared to ice-pack-negative patients and normal controls. The prolonged effect of cooling continued until the end of recording even though decremental response to RNS had returned to baseline value.ConclusionsCooling of myasthenic muscle may induce two effects. One is relatively short effect on electrical synaptic transmission at the endplate, and another is prolonged effect on E-C coupling in the muscle.SignificanceThe ice-pack test induces a prolonged effect of ameliorating impaired E-C coupling in MG.



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Reduced motor cortical inhibition in migraine: A blinded transcranial magnetic stimulation study

Publication date: December 2017
Source:Clinical Neurophysiology, Volume 128, Issue 12
Author(s): J.P. Neverdahl, P.M. Omland, M. Uglem, M. Engstrøm, T. Sand
ObjectiveTo investigate motor cortical excitability, inhibition, and facilitation with navigated transcranial magnetic stimulation (TMS) in migraine in a blinded cross-sectional study.MethodsResting motor threshold (RMT), cortical silent period (CSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) were compared in 27 interictal migraineurs and 33 controls. 24 female interictal migraineurs and 27 female controls were compared in subgroup analyses. Seven preictal migraineurs were also compared to the interictal group in a hypothesis-generating analysis. Investigators were blinded for diagnosis during recording and analysis of data.ResultsSICI was decreased in interictal migraineurs when compared to healthy controls (p=0.013), CSP was shortened in female interictal migraineurs (p=0.041). ICF was decreased in preictal compared to interictal migraineurs (p=0.023). RMT and ICF were not different between interictal migraineurs and controls.ConclusionCortical inhibition was decreased in migraineurs between attacks, primarily in a female subgroup, indicating an importance of altered cortical inhibition in migraine.SignificancePrevious studies on motor cortical excitability in migraineurs have yielded varying results. This relatively large and blinded study provides support for altered cortical inhibition in migraine. Measuring intracortical facilitation in the period preceding migraine attacks may be of interest for future studies.



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Intermittent theta-burst stimulation induces correlated changes in cortical and corticospinal excitability in healthy older subjects

Publication date: December 2017
Source:Clinical Neurophysiology, Volume 128, Issue 12
Author(s): Tamara Gedankien, Peter J. Fried, Alvaro Pascual-Leone, Mouhsin M. Shafi
ObjectiveWe studied the correlation between motor evoked potentials (MEPs) and early TMS-evoked EEG potentials (TEPs) from single-pulse TMS before and after intermittent Theta Burst Stimulation (iTBS) to the left primary motor cortex (M1) in 17 healthy older participants.MethodsTMS was targeted to the hand region of M1 using a MRI-guided navigated brain stimulation system and a figure-of-eight biphasic coil. MEPs were recorded from the right first dorsal interosseous muscle using surface EMG. TEPs were extracted from a 61-channel EEG recording. Participants received 90 single TMS pulses at 120% of resting motor threshold before and after iTBS.ResultsAcross all participants, the change in N15-P30 TEP and MEP amplitudes were significantly correlated (r=0.69; p<0.01). Average TEP responses did not change significantly after iTBS, whereas MEP amplitudes showed a significant increase.ConclusionsChanges in corticospinal reactivity and cortical reactivity induced by iTBS are related. However, the effect of iTBS on TEPs, unlike MEPs, is not straightforward.SignificanceOur findings help elucidate the relationship between changes in cortical and corticospinal excitability in healthy older individuals. Going forward, TEPs may be used to evaluate the effects of theta-burst stimulation in non-motor brain regions.



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Corticomuscular coherence in the acute and subacute phase after stroke

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Lisbeth Hoejkjaer Larsen, Ivan Chrilles Zibrandtsen, Troels Wienecke, Troels Wesenberg Kjaer, Mark Schram Christensen, Jens Bo Nielsen, Henning Langberg
ObjectiveStroke is one of the leading causes of physical disability due to damage of the motor cortex or the corticospinal tract. In the present study we set out to investigate the role of adaptations in the corticospinal pathway for motor recovery during the subacute phase after stroke.MethodsWe examined 19 patients with clinically diagnosed stroke and 18 controls. The patients had unilateral mild to moderate weakness of the hand. Each patient attended two sessions at approximately 3days (acute) and 38days post stroke (subacute). Task-related changes in the communication between motor cortex and muscles were evaluated from coupling in the frequency domain between EEG and EMG during movement of the paretic hand.ResultsCorticomuscular coherence (CMC) and intermuscular coherence (IMC) were reduced in patients as compared to controls. Paretic hand motor performance improved within 4–6weeks after stroke, but no change was observed in CMC or IMC.ConclusionsCMC and IMC were reduced in patients in the early phase after stroke. However, changes in coherence do not appear to be an efficient marker for early recovery of hand function following stroke.SignificanceThis is the first study to demonstrate sustained reduced coherence in acute and subacute stroke.



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Editorial Board

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11





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Contents

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11





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4. Prevention of trauma-induced epileptogenesis in mice via manipulation of the network excitability

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): S. Soltani, J. Seigneur, S. Chauvette, I. Timofeev
A large proportion of patients with severe brain damage become epileptic several months to years after the trauma. The mechanisms leading to the development of epilepsy (epileptogenesis) are unknown. We hypothesize that brain damage leads to partial deafferentation and a drop in excitability of the affected area. To compensate, the brain employs a variety of mechanisms to restore this drop of excitability and if not properly controlled, this leads to epilepsy. We performed undercut in the somatosensory area in adult C57/BL6 mice and implanted LFP and EMG electrodes for continuous electrographic recordings for at least two months. We proposed to manipulate (increase or decrease) network activities in order to prevent/enhance epileptogenesis applying DREADD technology. Target cortical regions were injected with AAV-hM3D(Gq) or AAV-hM4D(Gi). Activation of the designed receptor in infected neurons was achieved by clozapine-N-oxide continuously injected via an osmotic pump. Activation of hM3D(Gq) leads to depolarization and increased firing in infected neurons, while the activation of hM4D(Gi) induces a hyperpolarization of neurons. If our hypothesis is true, we expect to obtain epileptogenesis in adult mice without DREADD manipulations, either abolition or strong reduction of epileptogenesis in hM3D(Gq) mice, and increased epileptogenesis symptoms in hM4D(Gi) mice. In the following weeks all adult mice without DREADD manipulations revealed recurrent seizure activities. Mice in which hM4D(Gi) was activated revealed earlier and more severe seizures. Mice with hM3D(Gq) activation did not reveal paroxysmal activities. These results will lead to the development of new preventive treatments of epileptogenesis induced by brain damage.Supported by CIHR and NSERC.



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Electrical impedance myography changes after incomplete cervical spinal cord injury: An examination of hand muscles

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Le Li, Henry Shin, Argyrios Stampas, Xiaoyan Li, Ping Zhou
ObjectiveThis study was to apply the newly developed electrical impedance myography (EIM) technique to examine hand muscles in patients with an incomplete cervical spinal cord injury (SCI).MethodsEIM was performed on the thenar, hypothenar, and first dorsal interosseous (FDI) muscles of SCI (n=16) and age-matched healthy control (n=18) subjects. By sending low intensity and high frequency current through the skin and measuring the consequent voltage, EIM estimates the major impedance parameters, which include resistance (R), reactance (X) and phase angle (θ).ResultsThe SCI group had lower reactance and phase angle (p<0.0001) as compared to the control group in all three muscles, and lower resistance in the thenar muscle (p<0.05). The SCI group also demonstrated a smaller anisotropy in resistance (p<0.0001) and larger anisotropy in phase angle (p<0.05) compared to those from healthy controls.ConclusionThe reduced reactance and phase angle of paralyzed muscles could be due tochanges of membrane integrity and fat infiltration, whereas the change in the anisotropy may reflect the rearrangement of muscle fiber geometry.SignificanceThe EIM provides a quick and convenient tool for examination of muscle alterations after SCI.



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Plasticity induced by non-invasive transcranial brain stimulation: A position paper

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Ying-Zu Huang, Ming-Kue Lu, Andrea Antal, Joseph Classen, Michael Nitsche, Ulf Ziemann, Michael Ridding, Masashi Hamada, Yoshikazu Ugawa, Shapour Jaberzadeh, Antonio Suppa, Walter Paulus, John Rothwell
Several techniques and protocols of non-invasive transcranial brain stimulation (NIBS), including transcranial magnetic and electrical stimuli, have been developed in the past decades. Non-invasive transcranial brain stimulation may modulate cortical excitability outlasting the period of non-invasive transcranial brain stimulation itself from several minutes to more than one hour. Quite a few lines of evidence, including pharmacological, physiological and behavioral studies in humans and animals, suggest that the effects of non-invasive transcranial brain stimulation are produced through effects on synaptic plasticity. However, there is still a need for more direct and conclusive evidence. The fragility and variability of the effects are the major challenges that non-invasive transcranial brain stimulation currently faces. A variety of factors, including biological variation, measurement reproducibility and the neuronal state of the stimulated area, which can be affected by factors such as past and present physical activity, may influence the response to non-invasive transcranial brain stimulation. Work is ongoing to test whether the reliability and consistency of non-invasive transcranial brain stimulation can be improved by controlling or monitoring neuronal state and by optimizing the protocol and timing of stimulation.



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After-effects of transcranial alternating current stimulation on evoked delta and theta power

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Miles Wischnewski, Dennis J.L.G. Schutter
ObjectivePhase synchronization is suggested to be among the mechanisms that can explain the effects of transcranial alternating current stimulation (tACS). However, little is known about the effects of tACS on event-related oscillatory activity. Therefore the objective was to investigate frequency-related effects of frontal tACS on event-related oscillatory power.MethodsIn a double blind randomized controlled cross-over design, twenty-four participants received 12min of delta (2.5Hz), theta tACS (5Hz) and sham tACS at an intensity of 1mA peak-to-peak. Event-related delta- and theta-related oscillatory activity was recorded to reward- and punishment-related feedback signals.ResultsDelta tACS decreased feedback-related oscillatory power in the 1.5 and 3.5Hz frequency range. This effect was driven by power changes below the tACS frequency stimulation.ConclusionExogenous field potentials can attenuate event-related oscillatory activity in a rhythm slightly below the stimulation frequency. Our findings suggest an interaction between tACS and event-related rhythmic activity that extends beyond phase synchronization.SignificanceThese findings add novel insights into the mechanisms of tACS after-effects.



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1. Across all the seven seas: Fifty years in neurology, EEG and epilepsies

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Paul Hwang
Since the 1960s, major neuroscience advances have facilitated the development of new antiepilepsy drugs (AEDs) targeting specific neurotransmitter-receptor systems, particularly the GABAergic, the NMDA-receptors and voltage-gated ion channels. In addition to the classical AEDs, carbamazepine and cogeners act at the voltage-gates sodium channels, while ethosuxumide acts at the calcium channel, improving the treatment of partial and generalized seizures. But approximately 30% of partial complex seizures remain refractory to AEDs, leading to novel AEDs: levetiracetam, tiagabine, lacosamide, perampanel and others. The pharmacoresistant epilepsies are typically dyscognitive partial-onset, arising from limbic structures of mesial temporal lobes, better visualised by improved neuroimaging methods eg. MRI and PET. Together with invasive intracranial monitoring in specialized units with long-term recording of multichannelled EEG and videorecording of behaviour, the localization of the seizure-onset zone has allowed targeted excision of the epileptogenic tissue for better outcome.Functional neurosurgical methods include vagal nerve stimulation and deep brain stimulation of selected targets in affected circuits, mapped by new EEG criteria including gamma rhythm, HFOs, ripples and clusters. Novel intervention in refractory epilepsies include the ketogenic diet and variants, neurosteroids, hormones eg. progestins and ACTH. A number of genetic mutations and copy number variants have been linked to epilepsies. It remains to be seen how expanded knowledge of the genetic bases of the epilepsies and epileptic encephalopathies leads to new intervention improving long-term prognosis and quality of life in persons afflicted with this ancient curse of the human condition, 'The Falling Sickness' also known as 'The Sacred Disease' (Hippocrates).In the words of Sir William Osler: 'He who studies medicine without books sails an uncharted sea, but he who studies medicine without patients does not go to sea at all' ('Aequanimitas' by Osler), quoted in Herbert Ho Ping Kong, 'The Art of Medicine: Healing and the Limits of Technology' (ECW Press, 2014 Toronto).



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3. Asymmetric hypsarrythmia: An insight into the pathophysiology of infantile spasms. A retrospective cohort

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): B. Desnous, M. Arbour, H.S. Nguyen, A. Lortie, D. Chartrand, E. Rossignol, P. Diadori, P. Major, L. Carmant, A. Birca
Infantile spasms (IS) is a catastrophic epilepsy where treatment precocity improves outcome. Previous studies demonstrated an association between asymmetric hypsarrhythmia on EEG and ipsilateral hemispheric lesions on MRI, suggesting a possible role of cortical lesions in the initiation of IS. Epileptiform abnormalities appearing during early infancy have also been linked to IS emergence. We hypothesized that focal lateralized EEG abnormalities during the prehyspasrrhythmic period will be associated with asymmetric hypsarrhythmia at IS onset.We recruited a retrospective cohort of 80 infants, 7.4±3.6months old at the onset of hypsarrhythmia and IS, admitted to Sainte-Justine Hospital between 2007 and 2016. Seven infants showed an asymmetric hypsarrhythmia pattern and, as expected, all of them had lateralized lesions on MRI. Of the remaining 73, 42 had abnormal MRI, but only 3 infants had lateralized lesions (100% vs 7.1%, p<0.01). Thirty-four patients had pre-hypsarrhythmic EEG recordings at the age of 4.6±2.6months, 3±2months before IS onset, including four infants with asymmetric hypsarrhythmia. Five infants had no pre-hypsarrhythmic epileptiform abnormalities.Six had focal lateralized, while 23 multifocal abnormalities. The proportion of patients with focal abnormalities was higher in those who developed asymmetric compared to symmetric hypsarrhythmia (50% vs 13.3%, p<0.05).Our data confirm the link between asymmetric hypsarrhythmia and lateralized MRI lesions. Moreover, we show that focal lateralized EEG abnormalities precede asymmetric hypsarrythmia, which supports the involvement of cerebral cortex in the IS genesis. More sensitive EEG biomarkers of high IS risk may help developing preventative treatments that will improve outcomes in IS.



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Neural network topology in ADHD; evidence for maturational delay and default-mode network alterations

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): T.W.P. Janssen, A. Hillebrand, A. Gouw, K. Geladé, R. Van Mourik, A. Maras, J. Oosterlaan
ObjectiveAttention-deficit/hyperactivity disorder (ADHD) has been associated with widespread brain abnormalities in white and grey matter, affecting not only local, but global functional networks as well. In this study, we explored these functional networks using source-reconstructed electroencephalography in ADHD and typically developing (TD) children. We expected evidence for maturational delay, with underlying abnormalities in the default mode network.MethodsElectroencephalograms were recorded in ADHD (n=42) and TD (n=43) during rest, and functional connectivity (phase lag index) and graph (minimum spanning tree) parameters were derived. Dependent variables were global and local network metrics in theta, alpha and beta bands.ResultsWe found evidence for a more centralized functional network in ADHD compared to TD children, with decreased diameter in the alpha band (ηp²=0.06) and increased leaf fraction (ηp²=0.11 and 0.08) in the alpha and beta bands, with underlying abnormalities in hub regions of the brain, including default mode network.ConclusionsThe finding of a more centralized network is in line with maturational delay models of ADHD and should be replicated in longitudinal designs.SignificanceThis study contributes to the literature by combining high temporal and spatial resolution to construct EEG network topology, and associates maturational-delay and default-mode interference hypotheses of ADHD.



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5. Epilepsy and EEG activity in early-onset Alzheimer’s disease

Publication date: November 2017
Source:Clinical Neurophysiology, Volume 128, Issue 11
Author(s): Ángela Milán-Tomás, Paul Hwang
ObjectiveThe aim of this review was to evaluate and summarize the current literature regarding the incidence and features of epileptic seizures in early onset Alzheimer's disease (AD) as well as its epileptiform characteristics as described by electroencephalography (EEG).BackgroundThe incidence of epilepsy in AD is higher than in the general population, although the true prevalence of seizures has remained unclear due to methodological problems detecting these events in a cognitively impaired population.Design/MethodsA literature search using Medline with PubMed and EMBASE was carried out identifying papers published focusing on EEG and epilepsy in early-onset Alzheimer's disease (EOAD). A total of 767 abstracts were obtained, 55 full publications were screened and references were checked for additional material where appropriate.ResultsOnly 20 studies included EEG data regarding epilepsy in Alzheimer's disease of which 11 were animal models. AD due to amyloid precursor protein (APP) mutations has been described as one of the most common early-onset AD forms presenting with epileptic seizures. Neurodegeneration of the hippocampal region causing aberrant excitatory neuronal activity is the most accepted hypothesis for the occurrence of epilepsy in AD.ConclusionsThere is a need for better methodological studies addressing the role of EEG in the diagnosis and characterization of seizures in AD. Subclinical epileptiform activity may lead to a faster decline in cognition and they occur more often during sleep stages, therefore a prolonged sleep EEG can be an effective diagnostic tool for detecting this activity.



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Neuronal expression patterns of the PlexinA family during zebrafish development

Publication date: Available online 28 October 2017
Source:Gene Expression Patterns
Author(s): Sarah E. Emerson, Sarah E. Light, Alicia M. Ebert
Plexins (Plxns) and Semaphorins (Semas) are key signaling molecules that regulate many aspects of development. Plxns are a family of transmembrane protein receptors that are activated upon extracellular binding by Semas. Activated Plxns trigger intracellular signaling cascades, which regulate a range of developmental processes, including axon guidance, neuronal positioning and vasculogenesis. Semas are a large family of both transmembrane and secreted signaling molecules, and show subtype specific binding to different Plxn family members. Each Plxn can play different roles in development, and so tightly regulated temporal and spatial expression of receptor subtypes is critical to ensure appropriate signaling. Here we elucidate the expression profiles of the plxnA family, plxnA1a, A1b, A2, A3 and A4 at 18, 24, 36, 48, 60 and 72 h post fertilization in the developing zebrafish. We show that PlxnA family members are expressed in neuronal tissues during zebrafish development, but exhibit key differences in expression within these tissues. We also highlight that plxnA1 has two genes in zebrafish, A1a and A1b, which show divergences in expression patterns during early development.



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Tanner–Whitehouse Skeletal Ages in Male Youth Soccer Players: TW2 or TW3?

Abstract

Background

The Tanner–Whitehouse radius-ulna-short bone protocol (TW2 RUS) for the assessment of skeletal age (SA) is widely used to estimate the biological (skeletal) maturity status of children and adolescents. The scale for converting TW RUS ratings to an SA has been revised (TW3 RUS) and has implications for studies of youth athletes in age-group sports.

Objectives

The aim of this study was to compare TW2 and TW3 RUS SAs in an international sample of male youth soccer players and to compare distributions of players by maturity status defined by each SA protocol.

Methods

SA assessments with the TW RUS method were collated for 1831 male soccer players aged 11–17 years from eight countries. RUS scores were converted to TW2 and TW3 SAs using the appropriate tables. SAs were related to chronological age (CA) in individual athletes and compared by CA groups. The difference of SA minus CA with TW2 SA and with TW3 SA was used to classify players as late, average, or early maturing with each method. Concordance of maturity classifications was evaluated with Cohen's Kappa coefficients.

Results

For the same RUS score, TW3 SAs were systematically and substantially reduced compared with TW2 SAs; mean differences by CA group ranged from − 0.97 to − 1.16 years. Kappa coefficients indicated at best fair concordance of TW2 and TW3 maturity classifications. Across the age range, 42% of players classified as average with TW2 SA were classified as late with TW3 SA, and 64% of players classified as early with TW2 SA were classified as average with TW3 SA.

Conclusion

TW3 SAs were systematically lower than corresponding TW2 SAs in male youth soccer players. The differences between scales have major implications for the classification of players by maturity status, which is central to some talent development programs.

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Talent Identification in Sport: A Systematic Review

Abstract

Background

Talent identification (TID) programs are an integral part of the selection process for elite-level athletes. While many sport organizations utilize TID programs, there does not seem to be a clear set of variables that consistently predict future success.

Objective

This review aims to synthesize longitudinal and retrospective studies examining differences between performance variables in highly skilled and less-skilled athletes in elite-level sport.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to identify relevant studies (N = 20).

Results

There was a clear overrepresentation of studies that (1) examined physical profiles of athletes (60%); (2) focused on male samples (65%); (3) examined athletes between the ages of 10 and 20 years (60%); and (4) were published between the years 2010 and 2015 (65%). On closer examination, there was a high degree of variability in the factors that were found to discriminate between skilled and less-skilled individuals.

Conclusion

Findings from this review highlight how little is known about TID in elite sport and emphasize the need for greater diversity in TID research.

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Acknowledgment to Reviewers

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Rapidly growing hepatocellular carcinoma after direct-acting antiviral treatment of chronic hepatitis C

Abstract

We report on a 62-year-old man with chronic hepatitis C who developed rapidly growing hepatocellular carcinoma (HCC) after achieving sustained virological response at post-treatment week 24 (SVR 24) by direct-acting antiviral (DAA) treatment. In 2008, he failed interferon therapy at 56 years of age. He received daclatasvir plus asunaprevir for 24 weeks after confirmation of no liver tumor by abdominal ultrasonography. He had no advanced liver fibrosis. Three months after initiation of DAA treatment, a liver tumor measuring 6 mm in diameter was detected by ultrasonography and confirmed with magnetic resonance imaging. After achieving SVR 24, the tumor increased in size to 16 mm. Two months later, a tumor biopsy was performed, and histology revealed moderately to poorly differentiated HCC. The patient's alpha-fetoprotein (AFP) level was within the normal range, but the Lens culinaris agglutinin-reactive fraction of AFP level was elevated. The diameter of the tumor increased to 32 mm at 2 months after diagnosis. Lymph node metastasis in porta hepatis was found by positron emission tomography at 4 months after diagnosis. The patient received hepatic arterial infusion chemotherapy and radiation therapy, but died later. Careful monitoring is required during and after DAA treatment because HCC can grow fast even in patients with normal AFP and no advanced liver fibrosis.

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