Focal Cerebral Ischemia Model by Endovascular Suture Occlusion of the Middle Cerebral Artery in the Rat

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable clinical state; in the development of animal models of focal ischemia, however, achieving reproducibility of experimentally induced infarct volume is essential. The rat is a widely used animal model for stroke due to its relatively low animal husbandry costs and to the similarity of its cranial circulation to that of humans2,3. In humans, the middle cerebral artery (MCA) is most commonly affected in stroke syndromes and multiple methods of MCA occlusion (MCAO) have been described to mimic this clinical syndrome in animal models. Because recanalization commonly occurs following an acute stroke in the human, reperfusion after a period of occlusion has been included in many of these models. In this video, we demonstrate the transient endovascular suture MCAO model in the spontaneously hypertensive rat (SHR). A filament with a silicon tip coating is placed intraluminally at the MCA origin for 60 minutes, followed by reperfusion. Note that the optimal occlusion period may vary in other rat strains, such as Wistar or Sprague-Dawley. Several behavioral indicators of stroke in the rat are shown. Focal ischemia is confirmed using T2-weighted magnetic resonance images and by staining brain sections with 2,3,5-triphenyltetrazolium chloride (TTC) 24 hours after MCAO

Possible role of SCN4A skeletal muscle mutation in apnoea during seizure

SCN4A gene mutations cause a number of neuromuscular phenotypes including myotonia. A subset of infants with myotonia‐causing mutations experience severe life‐threatening episodic laryngospasm with apnea. We have recently identified similar SCN4A mutations in association with sudden infant death syndrome. Laryngospasm has also been proposed as a contributory mechanism to some cases of sudden unexpected death in epilepsy (SUDEP). We report an infant with EEG‐confirmed seizures and recurrent apneas. Whole‐exome sequencing identified a known pathogenic mutation in the SCN4A gene that has been reported in several unrelated families with myotonic disorder. We propose that the SCN4A mutation contributed to the apneas in our case, irrespective of the underlying cause of the epilepsy. We suggest this supports the notion that laryngospasm may contribute to some cases of SUDEP, and implicates a possible shared mechanism between a proportion of sudden infant deaths and sudden unexpected deaths in epilepsy

Close binary stars in the solar-age Galactic open cluster M67

We present multi-colour time-series CCD photometry of the solar-age galactic open cluster M67 (NGC 2682). About 3600 frames spread over 28 nights were obtained with the 1.5 m Russian-Turkish and 1.2 m Mercator telescopes. High-precision observations of the close binary stars AH Cnc, EV Cnc, ES Cnc, the $\delta$ Scuti type systems EX Cnc and EW Cnc, and some long-period variables belonging to M67 are presented. Three full multi-colour light curves of the overcontact binary AH Cnc were obtained during three observing seasons. Likewise we gathered three light curves of EV Cnc, an EB-type binary, and two light curves of ES Cnc, a blue straggler binary. Parts of the light change of long-term variables S1024, S1040, S1045, S1063, S1242, and S1264 are obtained. Period variation analysis of AH Cnc, EV Cnc, and ES Cnc were done using all times of mid-eclipse available in the literature and those obtained in this study. In addition, we analyzed multi-colour light curves of the close binaries and also determined new frequencies for the $\delta$ Scuti systems. The physical parameters of the close binary stars were determined with simultaneous solutions of multi-colour light and radial velocity curves. Finally we determined the distance of M67 as 857(33) pc via binary star parameters, which is consistent with an independent method from earlier studies.Comment: 12 pages, 9 Figures, 13 Table

Overlapping frontoparietal networks for tactile and visual parametric working memory representations

Previous working memory (WM) research based on non-human primate electrophysiology and human EEG has shown that frontal brain regions maintain frequencies of flutter stimulation across different sensory modalities by means of a supramodal parametric WM code. These findings imply that frontal regions encode the memorized frequencies in a sensory-unspecific, quantitative format. Here, we explored which brain regions maintain information about frequencies provided by different sensory modalities at the level of activity pattern across fMRI voxel populations. Moreover, we sought evidence for a supramodal multivariate WM representation. Participants maintained the same set of frequencies of tactile vibration and visual flicker for a 6 s WM delay in a frequency discrimination task. A support vector regression model for multivariate pattern analysis was applied. We observed that sensory cortices were only selective for memoranda of their corresponding modalities, while frontoparietal regions exhibited distinguishable activity patterns to memorized frequencies regardless of sensory modality. A common multivariate code was not evident in our data. Collectively, we show that mnemonic representations for stimulus frequencies are maintained throughout the cortical hierarchy, in line with the suggested transformation of information across different representational formats. Although evidence for a supramodal multivariate code is absent, our findings underpin the generalized role of the frontoparietal cortex for maintaining quantitative information across sensory modalities