Mapping Interictal activity in epilepsy using a hidden Markov model: A magnetoencephalography study

Abstract: Epilepsy is a highly heterogeneous neurological disorder with variable etiology, manifestation, and response to treatment. It is imperative that new models of epileptiform brain activity account for this variability, to identify individual needs and allow clinicians to curate personalized care. Here, we use a hidden Markov model (HMM) to create a unique statistical model of interictal brain activity for 10 pediatric patients. We use magnetoencephalography (MEG) data acquired as part of standard clinical care for patients at the Children's Hospital of Philadelphia. These data are routinely analyzed using excess kurtosis mapping (EKM); however, as cases become more complex (extreme multifocal and/or polymorphic activity), they become harder to interpret with EKM. We assessed the performance of the HMM against EKM for three patient groups, with increasingly complicated presentation. The difference in localization of epileptogenic foci for the two methods was 7 ± 2 mm (mean ± SD over all 10 patients); and 94% ± 13% of EKM temporal markers were matched by an HMM state visit. The HMM localizes epileptogenic areas (in agreement with EKM) and provides additional information about the relationship between those areas. A key advantage over current methods is that the HMM is a data‐driven model, so the output is tuned to each individual. Finally, the model output is intuitive, allowing a user (clinician) to review the result and manually select the HMM epileptiform state, offering multiple advantages over previous methods and allowing for broader implementation of MEG epileptiform analysis in surgical decision‐making for patients with intractable epilepsy

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

Interictal activity is an important contributor to abnormal intrinsic network connectivity in paediatric focal epilepsy

Patients with focal epilepsy have been shown to have reduced functional connectivity in intrinsic connectivity networks (ICNs), which has been related to neurocognitive development and outcome. However, the relationship between interictal epileptiform discharges (IEDs) and changes in ICNs remains unclear, with evidence both for and against their influence. EEG-fMRI data was obtained in 27 children with focal epilepsy (mixed localisation and aetiologies) and 17 controls. A natural stimulus task (cartoon blocks verses blocks where the subject was told "please wait") was used to enhance the connectivity within networks corresponding to ICNs while reducing potential confounds of vigilance and motion. Our primary hypothesis was that the functional connectivity within visual and attention networks would be reduced in patients with epilepsy. We further hypothesized that controlling for the effects of IEDs would increase the connectivity in the patient group. The key findings were: (1) Patients with mixed epileptic foci showed a common connectivity reduction in lateral visual and attentional networks compared with controls. (2) Having controlled for the effects of IEDs there were no connectivity differences between patients and controls. (3) A comparison within patients revealed reduced connectivity between the attentional network and basal ganglia associated with interictal epileptiform discharges. We also found that the task activations were reduced in epilepsy patients but that this was unrelated to IED occurrence. Unexpectedly, connectivity changes in ICNs were strongly associated with the transient effects of interictal epileptiform discharges. Interictal epileptiform discharges were shown to have a pervasive transient influence on the brain's functional organisation

Simultaneous whole-head electrophysiological recordings using EEG and OPM-MEG

Electroencephalography (EEG) and magnetoencephalography (MEG) non-invasively measure human brain electrophysiology. They differ in nature; MEG offers better performance whilst EEG (a wearable platform) is more practical. They are also complementary, with studies showing that concurrent MEG/EEG provides advantages over either modality alone, and consequently clinical guidelines for MEG in epilepsy recommend simultaneous acquisition of MEG and EEG. In recent years, new instrumentation— the optically pumped magnetometer (OPM)— has had a significant impact on MEG, offering improved performance, lifespan compliance, and wearable MEG systems. Nevertheless, the ability to carry out simultaneous EEG/OPM-MEG remains critical. Here, we investigated whether simultaneous, wearable, whole-head EEG and OPM-MEG measurably degrades signal quality in either modality. We employed two tasks: a motor task known to modulate beta oscillations, and an eyes-open/closed task known to modulate alpha oscillations. In both, we characterised the performance of EEG alone, OPM-MEG alone, and concurrent EEG/OPM-MEG. Results show that the SNR of the beta response was similar, regardless of whether modalities were used individually or concurrently. Likewise, our alpha band recordings demonstrated that signal contrast was stable, regardless of the concurrent recording. We also demonstrate significant advantages of OPM-MEG; specifically, the OPM-MEG signal is less correlated across channels and less susceptible to interference from non-brain sources. Our results suggest that there are no barriers to simultaneous wearable EEG/OPM-MEG, and consequently this technique is ripe for neuroscientific and clinical adoption. This will be important in the clinic where simultaneous EEG and OPM-MEG recordings will facilitate better interpretation of OPM-MEG data in patients

History of the Book in Canada. Volume III : 1918-1980

"The History of the Book in Canada is one of this country's great scholarly achievements, with three volumes spanning topics from Aboriginal communication systems established prior to European contact to the arrival of multinational publishing companies. Each volume observes developments in the realms of writing, publishing, dissemination, and reading, illustrating the process of a fledgling nation coming into its own. The third and final volume follows book history and print culture from the end of the First World War to 1980, discussing the influences on them of the twentieth century, including the country's growing demographic complexity and the rise of multiculturalism." -- Front flap of jacket

Histoire du livre et de l’imprimé au Canada, Volume III

Au Canada, le XXe siècle inaugure une époque faste en matière de culture du livre et de l’imprimé. Après la Première Guerre mondiale, l’émergence de maisons d’édition indépendantes, d’associations d’auteurs, la création de prix littéraires et scientifiques et de subventions à la production, notamment au Québec, sont autant de signes de la vitalité du livre dans la transmission et la promotion d’une culture nationale, désormais projetée dans la durée et conçue comme un héritage essentiel. C’est ainsi que l’on peut voir se développer une culture du livre distincte de l’imprimerie et de la presse, où les éditeurs deviennent progressivement des architectes de la culture canadienne. Ce troisième volume de l’Histoire du livre et de l’imprimé au Canada couvre la période de 1918 à 1980, durant laquelle des transformations cruciales ont eu lieu. Ainsi, les deux grands groupes linguistiques du pays s’enrichissent de structures éditoriales distinctes, et grâce aux périodiques, les populations autochtones et les communautés ethniques et religieuses s’approprient les outils de la communication écrite pour exprimer leurs valeurs, affirmer leur appartenance sociale et créer des liens de solidarité. La Deuxième Guerre mondiale crée une demande nationale accrue pour le livre canadien qui se déploie alors sur la scène internationale. Au même moment, le cinéma, la radio et la télévision, phénomènes nouveaux, favorisent la pénétration d’une production de masse en provenance des États-Unis. L’affirmation d’une identité canadienne s’accentue encore dans les années 1960 au moment où les littératures canadienne et québécoise connaissent une période d’effervescence sans précédent. Enfin, après plus d’un siècle de luttes et de revendications, d’actions individu­elles et collectives, les gouvernements mettent en place des structures de soutien à la création littéraire et au livre qui en assureront l’essor au cours des années 1980

Behavioral responses of terrestrial mammals to COVID-19 lockdowns (code)

COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable, with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns, 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12%, and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide

Behavioral responses of terrestrial mammals to COVID-19 lockdowns

COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable, with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns, 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12%, and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide