Abnormal cortical brain integration of somatosensory afferents in ALS

Publication date: Available online 24 December 2017
Source:Clinical Neurophysiology
Author(s): Sina Sangari, Alain Giron, Guillaume Marrelec, Pierre-François Pradat, Véronique Marchand-Pauvert
ObjectivesInfraclinical sensory alterations have been reported at early stages of amyotrophic lateral sclerosis (ALS). While previous studies mainly focused on early somatosensory evoked potentials (SEPs), late SEPs, which reflect on cortical pathways involved in cognitive-motor functions, are relatively underinvestigated. Early and late SEPs were compared to assess their alterations in ALS.MethodsMedian and ulnar nerves were electrically stimulated at the wrist, at 9 times the perceptual threshold, in 21 ALS patients without clinical evidence of sensory deficits, and 21 age- and gender-matched controls. SEPs were recorded at the Erb point using surface electrodes and using a needle inserted in the scalp, in front of the primary somatosensory area (with reference electrode on the ear lobe).ResultsCompared to controls, ALS patients showed comparable peripheral (N9) and early cortical component (N20, P25, N30) reductions, while the late cortical components (N60, P100) were more depressed than the early ones.ConclusionsThe peripheral sensory alteration likely contributed to late SEP depression to a lesser extent than that of early SEPs.SignificanceLate SEPs may provide new insights on abnormal cortical excitability affecting brain areas involved in cognitive-motor functions.



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Nuclear accident consequence assessment in Hong Kong using JRODOS

Publication date: March 2018
Source:Journal of Environmental Radioactivity, Volume 183
Author(s): W.H. Leung, W.M. Ma, Philip K.Y. Chan
The JRODOS (Java-based Real-time Online DecisiOn Support) is a decision support system for off-site emergency management for releases of radioactive material into the environment. This paper documents the application of JRODOS by the Hong Kong Observatory in accident consequence assessment and emergency preparedness studies. For operational considerations, the most computational efficient dispersion model in JRODOS, ATSTEP, is adopted. Verification studies for JRODOS's ATSTEP model have been conducted. Comparison with tracer experiment results showed that under neutral atmospheric conditions and distances up to 50 km, the JRODOS simulation outputs were in general of the same order of magnitude with the tracer data. To further evaluate the capability of JRODOS in short-range simulation, a case study on the Fukushima nuclear power plant accident was also carried out. JRODOS was able to produce realistic simulation results which were comparable to the actual airborne monitoring data of the Cs-137 ground deposition from the Fukushima accident.Furthermore, the results of a comprehensive study to assess the potential consequences of accidents at a nearby nuclear power station are presented. Simulation using the French S3 source term for the Guangdong Nuclear Power Station at Daya Bay showed that the projected effective doses within Hong Kong remain far below the IAEA generic criteria of projected dose for urgent protective actions in sheltering/evacuation, while the projected equivalent dose in thyroid may meet the IAEA generic criteria for use of thyroid blocking agent at some areas in the northeastern part of Hong Kong, at distances of up to about 40 km from Daya Bay depending on the prevailing weather conditions in different seasons.



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ERP components associated with an indirect emotional stop signal task in healthy and depressed participants

Publication date: Available online 24 December 2017
Source:International Journal of Psychophysiology
Author(s): D.A. Camfield, T.K. Burton, F.M. De Blasio, R.J. Barry, R.J. Croft
Recent research has provided evidence to suggest that emotional stimuli may interfere with response inhibition, due to automatic capture of attention. Whilst previous studies have provided data regarding changes to event-related potentials (ERPs) in emotional Go/NoGo tasks, few studies to-date have utilized an emotional stop signal task (SST). Thirty-five participants were included in the study; 21 healthy controls and 14 depressed. An indirect emotional SST was employed, which consisted of the presentation of neutral, negative or positive visual images. The primary two-choice reaction time task required responding to frame colour (red or blue), whilst in 33% of trials an auditory stop signal was presented, with stop signal delay adjusted according to an adaptive tracking procedure. ERPs associated with both the primary visual task and the auditory SST were analysed using temporal principle components analysis (tPCA). In the primary task, reaction times were found to be slower for negative compared to neutral images. Stop signal reaction time (SSRT) was not found to be affected by image category or depression status. However, the NoGo-N2 component was found to be reduced for positive images, whilst the NoGo-P3 component was reduced for both positive and negative images in comparison to neutral images in the stop signal task. This effect was found to be enhanced for the depressed participants, indicating that inhibitory processing in the presence of positive stimuli may be inhibited to a greater extent in depressed individuals than in healthy controls. These findings provide further evidence for the ability of emotional valence and major depressive disorder to influence inhibitory processing.



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Cortisol awakening response and emotion at extreme altitudes on Mount Kangchenjunga

Publication date: Available online 24 December 2017
Source:International Journal of Psychophysiology
Author(s): Raúl Aguilar, Carlos Martínez, José R. Alvero-Cruz
The cortisol awakening response (CAR) was examined over a 45days stay at extreme altitudes (above of about 5500m) on Mount Kangchenjunga. The CAR refers to a peak cortisol response during the waking period that is superimposed to the diurnal rhythmicity in cortisol secretion, whose function has been proposed to be the anticipation of demands of the upcoming day (the CAR anticipation hypothesis). According to this hypothesis, we distinguished between resting days on which the expedition team engaged in routine activities in the base camp, and ascent days on which it planned to climb up a very demanding track. We were also interested in examining the association of testosterone with emotional anticipation, given the role of this steroid hormone in reward-related processes in challenge situations. Results showed that the climber group had a bigger CAR on ascent days, relative to the Sherpa group at the same altitude and the non-climber group at sea level. Several methodological issues, however, made it difficult to interpret these group differences in terms of the CAR anticipation hypothesis (e.g. a seemingly influential covariate was awakening time). Although based on tentative results, correlational and regression analyses controlling for awakening time coherently showed that the CAR was associated with anticipation of a hard day and feelings of fear, and testosterone was associated with feelings of energy and positive affect. Whether or not the anticipation of a hard day played a key role in regulation of the CAR, the observation of an intact CAR in the climber group under hypobaric hypoxia conditions would require in-depth reflection from the perspective of human adaptive evolution.



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Exertional Tolerance Assessments after Mild Traumatic Brain Injury: A Systematic Review

Publication date: Available online 23 December 2017
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Catherine Quatman-Yates, Anna Bailes, Sara Constand, Mary Claire Sroka, Katharine Nissen, Brad Kurowski, Jason Hugentobler
ObjectiveThe objective of this study was to review the literature to identify and summarize strategies for evaluating responses to physical exertion after mild traumatic brain injury (mTBI) for clinical and research purposes.Data sourcesPubMed and EBSCOHost through December 31, 2016.Study SelectionTwo independent reviewers selected studies based on the following criteria: 1) inclusion of participants with mTBI/concussion, 2) use of a measurement of physiological or psychosomatic response to exertion, 3) a repeatable description of the exertion protocol was provided, 4) a sample of at least 10 participants with a mean age between 8-65 years, and 5) the article was in English. The search process yielded 2,685 articles, of which 14 studies met the eligibility requirements.Data ExtractionA quality assessment using a checklist was conducted for each study by two independent study team members and verified by a third team member. Data were extracted by a one team member and verified by a second team member.Data SynthesisA qualitative synthesis of the studies revealed that most protocols employed a treadmill or cycle ergometer as the exercise modality. Protocol methods varied across studies including differences in initial intensity determination, progression parameters, and exertion duration. Common outcome measures were self-reported symptoms, heart rate, and blood pressure.Summary/conclusionsThe strongest evidence indicates that exertional assessments can provide important insight about mTBI recovery and should be administered using symptoms as a guide. Additional studies are needed to verify an optimal modes and protocols for post-mTBI exertional assessments.



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Arabidopsis ENOR3 regulates RNAi-mediated antiviral defense

Publication date: Available online 24 December 2017
Source:Journal of Genetics and Genomics
Author(s): Hua Gao, Mai Yang, Haitao Yang, Yue Qin, Biyun Zhu, Gang Xu, Chengyuan Xie, Dewei Wu, Xiaolin Zhang, Wanxiang Li, Jianbin Yan, Susheng Song, Tiancong Qi, Shou-Wei Ding, Daoxin Xie
Viruses can infect host plants to cause severe diseases and substantial agricultural loss, while plants have evolved RNA interference (RNAi) strategy to defend against viral infection. Despite enormous efforts, only a few host proteins in RNAi pathway were shown to mediate antiviral defense, including RNA-dependent RNA polymerase 1 (RDR1), RDR6, DICER-LIKE 2 (DCL2) and DCL4. In this study, we carried out a genetic screen for antiviral factors of RNAi pathway in Arabidopsis rdr6 background via inoculation with a 2b-deficient Cucumber Mosaic Virus (CMV-Δ2b). We identified a mutant susceptible to CMV-Δ2b, referred to as enhancer of rdr6 (enor) 3-1 rdr6, and found that ENOR3 encodes a functionally unknown protein with high homology to the mammalian Non Imprinted in Prader-Willi/Angelman (NIPA) magnesium transporters. ENOR3 inhibits accumulation of CMV-Δ2b and acts additively with RDR1, RDR6, DCL2 and DCL4 in antiviral defense. These results uncover that ENOR3 is a key component in antiviral RNAi pathway, and provide new insights into antiviral immunity.



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