NODDI in clinical research

Journal of Neuroscience Methods, Journal Year: 2020, Volume and Issue: 346, P. 108908 - 108908

Published: Aug. 16, 2020

Diffusion MRI (dMRI) has proven to be a useful imaging approach for both clinical diagnosis and research investigating the microstructures of nervous tissues, it helped us better understand neurophysiological mechanisms many diseases. Though diffusion tensor (DTI) long been default tool analyze dMRI data in research, acquisition with stronger weightings beyond DTI regimen is now possible modern scanners, potentially enabling even more detailed characterization tissue microstructures. To take advantage such data, neurite orientation dispersion density (NODDI) proposed as way relate signal features via biophysically inspired modeling. The number reports demonstrating potential utility NODDI rapidly increasing. At same time, pitfalls limitations NODDI, general challenges microstructure modeling, are becoming increasingly recognized by clinicians. modeling evolving field great promise, where people from different scientific backgrounds, physics, medicine, biology, neuroscience, statistics, collaborating build novel tools that contribute improving human healthcare. Here, we review applications discuss future perspectives investigations toward implementation practice.

Language: Английский

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The Kainic Acid Models of Temporal Lobe Epilepsy

eNeuro, Journal Year: 2021, Volume and Issue: 8(2), P. ENEURO.0337 - 20.2021

Published: March 1, 2021

Experimental models of epilepsy are useful to identify potential mechanisms epileptogenesis, seizure genesis, comorbidities, and treatment efficacy. The kainic acid (KA) model is one the most commonly used. Several modes administration KA exist, each producing different effects in a strain-, species-, gender-, age-dependent manner. In this review, we discuss advantages limitations various forms (systemic, intrahippocampal, intranasal), as well histologic, electrophysiological, behavioral outcomes strains species. We attempt personal perspective areas where work needed. diversity their offers researchers rich palette phenotypes, which may be relevant specific traits found patients with temporal lobe epilepsy.

Language: Английский

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Personalised virtual brain models in epilepsy

The Lancet Neurology, Journal Year: 2023, Volume and Issue: 22(5), P. 443 - 454

Published: March 24, 2023

Language: Английский

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Robust chronic convulsive seizures, high frequency oscillations, and human seizure onset patterns in an intrahippocampal kainic acid model in mice

Neurobiology of Disease, Journal Year: 2022, Volume and Issue: 166, P. 105637 - 105637

Published: Jan. 25, 2022

Intrahippocampal kainic acid (IHKA) has been widely implemented to simulate temporal lobe epilepsy (TLE), but evidence of robust seizures is usually limited. To resolve this problem, we slightly modified previous methods and show are common frequent in both male female mice. We employed continuous wideband video-EEG monitoring from 4 recording sites best demonstrate the seizures. found many more convulsive than most studies have reported. Mortality was low. Analysis at 2–4 10–12 wks post-IHKA showed a frequency (2–4 per day on average) duration (typically 20–30 s) each time. Comparison two timepoints that seizure burden became severe approximately 50% animals. almost all could be characterized as either low-voltage fast or hypersynchronous onset seizures, which not reported mouse model important because these types humans. In addition, report high oscillations (>250 Hz) occur, resembling findings IHKA rats TLE patients. Pathology hippocampus site injection similar mesial sclerosis reduced contralaterally. summary, our produce mice with there variable progression. HFOs also, patterns pathology like human TLE. Although used for research, variation outcomes, showing few long-term, especially present an implementation robust, meaning they >10 s associated complex rhythmic activity recorded 2 hippocampal cortical sites. Seizure matched Importantly, low mortality, sexes can used. believe results will advance ability use The also implications understanding HFOs, progression, other topics broad interest research community. Finally, preclinical drug screening increased half after 6 wk interval, suggesting typical period insufficient.

Language: Английский

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Amortized Bayesian inference on generative dynamical network models of epilepsy using deep neural density estimators

Neural Networks, Journal Year: 2023, Volume and Issue: 163, P. 178 - 194

Published: April 1, 2023

Whole-brain modeling of epilepsy combines personalized anatomical data with dynamical models abnormal activities to generate spatio-temporal seizure patterns as observed in brain imaging data. Such a parametric simulator is equipped stochastic generative process, which itself provides the basis for inference and prediction local global dynamics affected by disorders. However, calculation likelihood function at whole-brain scale often intractable. Thus, likelihood-free algorithms are required efficiently estimate parameters pertaining hypothetical areas, ideally including uncertainty. In this study, we introduce simulation-based virtual epileptic patient model (SBI-VEP), enabling us amortize approximate posterior process from low-dimensional representation patterns. The state-of-the-art deep learning conditional density estimation used readily retrieve statistical relationships between observations through sequence invertible transformations. We show that SBI-VEP able distribution linked extent epileptogenic propagation zones sparse intracranial electroencephalography recordings. presented Bayesian methodology can deal non-linear latent parameter degeneracy, paving way fast reliable on disorders neuroimaging modalities.

Language: Английский

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Degeneracy in epilepsy: multiple routes to hyperexcitable brain circuits and their repair

Communications Biology, Journal Year: 2023, Volume and Issue: 6(1)

Published: May 3, 2023

Abstract Due to its complex and multifaceted nature, developing effective treatments for epilepsy is still a major challenge. To deal with this complexity we introduce the concept of degeneracy field research: ability disparate elements cause an analogous function or malfunction. Here, review examples epilepsy-related at multiple levels brain organisation, ranging from cellular network systems level. Based on these insights, outline new multiscale population modelling approaches disentangle web interactions underlying design personalised multitarget therapies.

Language: Английский

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The critical dynamics of hippocampal seizures

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Aug. 13, 2024

Abstract Epilepsy is defined by the abrupt emergence of harmful seizures, but nature these regime shifts remains enigmatic. From perspective dynamical systems theory, such critical transitions occur upon inconspicuous perturbations in highly interconnected and can be modeled as mathematical bifurcations between alternative regimes. The predictability represents a major challenge, theory predicts appearance subtle signatures on verge instability. Whether measured before impending seizures uncertain. Here, we verified that predictions applied to onset hippocampal providing concordant results from silico modeling, optogenetics experiments male mice intracranial EEG recordings human patients with epilepsy. Leveraging pharmacological control over neural excitability, showed boundary physiological excitability inferred passively recorded or actively probed circuits. Of importance for design future neurotechnologies, active probing surpassed passive recording decode underlying levels notably when assessed network propagating responses. Our findings provide promising approach predicting preventing based sound understanding their dynamics.

Language: Английский

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Normative brain mapping of interictal intracranial EEG to localize epileptogenic tissue

Brain, Journal Year: 2021, Volume and Issue: 145(3), P. 939 - 949

Published: Oct. 7, 2021

Abstract The identification of abnormal electrographic activity is important in a wide range neurological disorders, including epilepsy for localizing epileptogenic tissue. However, this may be challenging during non-seizure (interictal) periods, especially if abnormalities are subtle compared to the repertoire possible healthy brain dynamics. Here, we investigate such interictal become more salient by quantitatively accounting dynamics location-specific manner. To end, constructed normative map dynamics, terms relative band power, from intracranial recordings 234 participants (21 598 electrode contacts). We then 62 patients with identify regions. proposed that most regions were spared surgery, would likely experience continued seizures postoperatively. first confirmed spatial variations power across consistent reported literature. Second, when variations, surgery than those resected only persistent postoperative (t = −3.6, P 0.0003), confirming our hypothesis. Third, found effect discriminated patient outcomes (area under curve 0.75 0.0003). Normative mapping well-established practice neuroscientific research. Our study suggests approach feasible detect EEG, and potential clinical value pathological tissue epilepsy. Finally, make publicly available facilitate future investigations beyond.

Language: Английский

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Loss of neuronal heterogeneity in epileptogenic human tissue impairs network resilience to sudden changes in synchrony

Cell Reports, Journal Year: 2022, Volume and Issue: 39(8), P. 110863 - 110863

Published: May 1, 2022

A myriad of pathological changes associated with epilepsy can be recast as decreases in cell and circuit heterogeneity. We thus propose recontextualizing epileptogenesis a process where reduction cellular heterogeneity, part, renders neural circuits less resilient to seizure. By comparing patch clamp recordings from human layer 5 (L5) cortical pyramidal neurons epileptogenic non-epileptogenic tissue, we demonstrate significantly decreased biophysical heterogeneity seizure-generating areas. Implemented computationally, this model prone sudden transitions into synchronous states increased firing activity, paralleling ictogenesis. This computational work also explains the surprising finding excitability population-activation functions tissue. Finally, mathematical analyses reveal bifurcation structure arising only low seizure-like dynamics. Taken together, provides experimental, computational, support for theory that ictogenic dynamics accompany

Language: Английский

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A unified physiological framework of transitions between seizures, sustained ictal activity and depolarization block at the single neuron level

Journal of Computational Neuroscience, Journal Year: 2022, Volume and Issue: 50(1), P. 33 - 49

Published: Jan. 15, 2022

Abstract The majority of seizures recorded in humans and experimental animal models can be described by a generic phenomenological mathematical model, the Epileptor. In this seizure-like events (SLEs) are driven slow variable occur via saddle node (SN) homoclinic bifurcations at seizure onset offset, respectively. Here we investigated SLEs single cell level using biophysically relevant neuron model including slow/fast system four equations. two equations for subsystem describe ion concentration variations fast delineate electrophysiological activities neuron. Using extracellular K + as variable, report that with SN/homoclinic readily when reaches critical value. patients models, also evolve into sustained ictal activity (SIA) depolarization block (DB), which parts dynamic repertoire Increasing to values found during status epilepticus DB, show SIA DB level. Thus, seizures, SIA, have been first identified network events, exist unified framework biophysical exhibit similar dynamics observed Author Summary: Epilepsy is neurological disorder characterized occurrence seizures. Seizures both macroscopic microscopic scales recordings. Experimental works allowed establishment detailed taxonomy models. We distinguish main types Phenomenological (generic) few parameters variables permit dynamical studies often capturing conditions. But they abstract parameters, making biological interpretation difficult. Biophysical on other hand, use large number due complexity systems represent. Because multiplicity solutions, it difficult extract general rules. present work, integrate approaches reduce sufficiently low-dimensional equations, thus maintaining advantages model. propose, level, different pathological block, activity.

Language: Английский

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