المؤلفون: Besne, Guillermo M., Evans, Nathan, Panagiotopoulou, Mariella, Smith, Billy, Chowdhury, Fahmida A, Diehl, Beate, Duncan, John S, McEvoy, Andrew W, Miserocchi, Anna, de Tisi, Jane, Walker, Mathew, Taylor, Peter N., Thornton, Chris, Wang, Yujiang

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: Anti-seizure medications (ASMs) are the primary treatment for epilepsy, yet medication tapering effects have not been investigated in a dose, region, and time-dependent manner, despite their potential impact on research and clinical practice. We examined over 3000 hours of intracranial EEG recordings in 32 subjects during long-term monitoring, of which 22 underwent concurrent ASM tapering. We estimated ASM plasma levels based on known pharmaco-kinetics of all the major ASM types. We found an overall decrease in the power of delta band activity around the period of maximum medication withdrawal in most (80%) subjects, independent of their epilepsy type or medication combination. The degree of withdrawal correlated positively with the magnitude of delta power decrease. This dose-dependent effect was strongly seen across all recorded cortical regions during daytime; but not in sub-cortical regions, or during night time. We found no evidence of differential effect in seizure onset, spiking, or pathological brain regions. The finding of decreased delta band power during ASM tapering agrees with previous literature. Our observed dose-dependent effect indicates that monitoring ASM levels in cortical regions may be feasible for applications such as medication reminder systems, or closed-loop ASM delivery systems. ASMs are also used in other neurological and psychiatric conditions, making our findings relevant to a general neuroscience and neurology audience.

الوصول الحر: http://arxiv.org/abs/2405.01385Test

المؤلفون: Woodhouse, Heather, Hall, Gerard, Simpson, Callum, Kozma, Csaba, Turner, Frances, Schroeder, Gabrielle M., Diehl, Beate, Duncan, John S., Mo, Jiajie, Zhang, Kai, Chari, Aswin, Tisdall, Martin, Moeller, Friederike, Petkov, Chris, Howard, Matthew A., Ibrahim, George M., Donner, Elizabeth, Warsi, Nebras M., Ahmed, Raheel, Taylor, Peter N., Wang, Yujiang

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: Background: Understanding healthy human brain function is crucial to identify and map pathological tissue within it. Whilst previous studies have mapped intracranial EEG (icEEG) from non-epileptogenic brain regions, these maps do not consider the effects of age and sex. Further, most existing work on icEEG has often suffered from a small sample size due to this modality's invasive nature. Here, we substantially increase the subject sample size compared to existing literature, to create a multi-centre, normative map of brain activity which additionally considers the effects of age, sex and recording site. Methods: Using interictal icEEG recordings from n = 513 subjects originating from 15 centres, we constructed a normative map of non-pathological brain activity by regressing age and sex on relative band power in five frequency bands, whilst accounting for the site effect. Results: Recording site significantly impacted normative icEEG maps in all frequency bands, and age was a more influential predictor of band power than sex. The age effect varied by frequency band, but no spatial patterns were observed at the region-specific level. Certainty about regression coefficients was also frequency band specific and moderately impacted by sample size. Conclusion: The concept of a normative map is well-established in neuroscience research and particularly relevant to the icEEG modality, which does not allow healthy control baselines. Our key results regarding the site and age effect guide future work utilising normative maps in icEEG.

الوصول الحر: http://arxiv.org/abs/2404.17952Test

المؤلفون: Janiukstyte, Vytene, Kozma, Csaba, Owen, Thomas W., Chaudhury, Umair J, Diehl, Beate, Lemieux, Louis, Duncan, John S, Rugg-Gunn, Fergus, de Tisi, Jane, Wang, Yujiang, Taylor, Peter N.

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: EEG slowing is reported in various neurological disorders including Alzheimer's, Parkinson's and Epilepsy. Here, we investigate alpha rhythm slowing in individuals with refractory temporal lobe epilepsy (TLE), compared to healthy controls, using scalp electroencephalography (EEG) and magnetoencephalography (MEG). We retrospectively analysed data from 17,(46) healthy controls and 22,(24) individuals with TLE who underwent scalp EEG and (MEG) recordings as part of presurgical evaluation. Resting-state, eyes-closed recordings were source reconstructed using the standardized low-resolution brain electrographic tomography (sLORETA) method. We extracted low (slow) 6-9 Hz and high (fast) 10-11 Hz alpha relative band power and calculated the alpha power ratio by dividing low (slow) alpha by high (fast) alpha. This ratio was computed for all brain regions in all individuals. Alpha oscillations were slower in individuals with TLE than controls (p<0.05). This effect was present in both the ipsilateral and contralateral hemispheres, and across widespread brain regions. Alpha slowing in TLE was found in both EEG and MEG recordings. We interpret greater low (slow)-alpha as greater deviation from health.

الوصول الحر: http://arxiv.org/abs/2404.10869Test

المؤلفون: Gascoigne, Sarah J., Evans, Nathan, Hall, Gerard, Kozma, Csaba, Panagiotopoulou, Mariella, Schroeder, Gabrielle M., Simpson, Callum, Thornton, Christopher, Turner, Frances, Woodhouse, Heather, Blickwedel, Jess, Chowdhury, Fahmida, Diehl, Beate, Duncan, John S., Faulder, Ryan, Thomas, Rhys H., Wilson, Kevin, Taylor, Peter N., Wang, Yujiang

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: Delineation of seizure onset regions from EEG is important for effective surgical workup. However, it is unknown if their complete resection is required for seizure freedom, or in other words, if post-surgical seizure recurrence is due to incomplete removal of the seizure onset regions. Retrospective analysis of icEEG recordings from 63 subjects (735 seizures) identified seizure onset regions through visual inspection and algorithmic delineation. We analysed resection of onset regions and correlated this with post-surgical seizure control. Most subjects had over half of onset regions resected (70.7% and 60.5% of subjects for visual and algorithmic methods, respectively). In investigating spatial extent of onset or resection, and presence of diffuse onsets, we found no substantial evidence of association with post-surgical seizure control (all AUC<0.7, p>0.05). Seizure onset regions tends to be at least partially resected, however a less complete resection is not associated with worse post-surgical outcome. We conclude that seizure recurrence after epilepsy surgery is not necessarily a result of failing to completely resect the seizure onset zone, as defined by icEEG. Other network mechanisms must be involved, which are not limited to seizure onset regions alone.

الوصول الحر: http://arxiv.org/abs/2311.14434Test

المؤلفون: Panagiotopoulou, Mariella, Thornton, Christopher, Chowdhury, Fahmida A, Diehl, Beate, Duncan, John S, Gascoigne, Sarah J, McEvoy, Andrew W, Miserocchi, Anna, Smith, Billy C, de Tisi, Jane, Taylor, Peter N, Wang, Yujiang

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: Chronobiological rhythms, such as the circadian rhythm, have long been linked to neurological disorders, but it is currently unknown how pathological processes affect the expression of biological rhythms in the brain. Here, we use the unique opportunity of long-term, continuous intracranially recorded EEG from 38 patients (totalling 6338 hours) to delineate circadian and ultradian rhythms in different brain regions. We show that functional circadian and ultradian rhythms are diminished in pathological tissue, independent of regional variations. We further demonstrate that these diminished rhythms are persistent in time, regardless of load or occurrence of pathological events. These findings provide the first evidence that brain pathology is functionally associated with persistently diminished chronobiological rhythms in vivo in humans, independent of regional variations or pathological events. Future work interacting with, and restoring, these modulatory chronobiological rhythms may allow for novel therapies.

الوصول الحر: http://arxiv.org/abs/2309.07271Test

المؤلفون: Owen, Thomas W., Janiukstyte, Vytene, Hall, Gerard R., Chowdhury, Fahmida A., Diehl, Beate, McEvoy, Andrew, Miserocchi, Anna, de Tisi, Jane, Duncan, John S., Rugg-Gunn, Fergus, Wang, Yujiang, Taylor, Peter N.

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: Intracranial EEG (iEEG) is the gold standard technique for epileptogenic zone (EZ) localisation, but requires a hypothesis of which tissue is epileptogenic, guided by qualitative analysis of seizure semiology and other imaging modalities such as magnetoencephalography (MEG). We hypothesised that if quantifiable MEG band power abnormalities were sampled by iEEG, then patients' post-resection seizure outcome were better. Thirty-two individuals with neocortical epilepsy underwent MEG and iEEG recordings as part of pre-surgical evaluation. Interictal MEG band power abnormalities were derived using 70 healthy controls as a normative baseline. MEG abnormality maps were compared to electrode implantation, with the spatial overlap of iEEG electrodes and MEG abnormalities recorded. Finally, we assessed if the implantation of electrodes in abnormal tissue, and resection of the strongest abnormalities determined by MEG and iEEG explained surgical outcome. Intracranial electrodes were implanted in brain tissue with the most abnormal MEG findings in individuals that were seizure-free post-resection (T=3.9, p=0.003). The overlap between MEG abnormalities and iEEG electrodes distinguished outcome groups moderately well (AUC=0.68). In isolation, the resection of the strongest MEG and iEEG abnormalities separated surgical outcome groups well (AUC=0.71, AUC=0.74 respectively). A model incorporating all three features separated outcome groups best (AUC=0.80). Intracranial EEG is a key tool to delineate the EZ and help render patients seizure-free after resection. We showed that data-driven abnormalities derived from interictal MEG recordings have clinical value and may help guide electrode placement in individuals with neocortical epilepsy. Finally, our predictive model of post-operative seizure-freedom, which leverages both MEG and iEEG recordings, may aid patient counselling of expected outcome.
Comment: 22 pages, 6 figures

الوصول الحر: http://arxiv.org/abs/2304.05199Test

المؤلفون: Janiukstyte, Vytene, Owen, Thomas W, Chaudhary, Umair J, Diehl, Beate, Lemieux, Louis, Duncan, John S, de Tisi, Jane, Wang, Yujiang, Taylor, Peter N

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: A normative electrographic activity map could be a powerful resource to understand normal brain function and identify abnormal activity. Here, we present a normative brain map using scalp EEG in terms of relative band power. In this exploratory study we investigate its temporal stability, its similarity to other imaging modalities, and explore a potential clinical application. We constructed scalp EEG normative maps of brain dynamics from 17 healthy controls using source-localised resting-state scalp recordings. We then correlated these maps with those acquired from MEG and intracranial EEG to investigate their similarity. Lastly, we use the normative maps to lateralise abnormal regions in epilepsy. Spatial patterns of band powers were broadly consistent with previous literature and stable across recordings. Scalp EEG normative maps were most similar to other modalities in the alpha band, and relatively similar across most bands. Towards a clinical application in epilepsy, we found abnormal temporal regions ipsilateral to the epileptogenic hemisphere. Scalp EEG relative band power normative maps are spatially stable across time, in keeping with MEG and intracranial EEG results. Normative mapping is feasible and may be potentially clinically useful in epilepsy. Future studies with larger sample sizes and high-density EEG are now required for validation.
Comment: 4 figures

الوصول الحر: http://arxiv.org/abs/2304.03204Test

المؤلفون: Horsley, Jonathan J, Thomas, Rhys H, Chowdhury, Fahmida A, Diehl, Beate, McEvoy, Andrew W, Miserocchi, Anna, de Tisi, Jane, Vos, Sjoerd B, Walker, Matthew C, Winston, Gavin P, Duncan, John S, Wang, Yujiang, Taylor, Peter N

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: When investigating suitability for surgery, people with drug-refractory focal epilepsy may have intracranial EEG (iEEG) electrodes implanted to localise seizure onset. Diffusion-weighted magnetic resonance imaging (dMRI) may be acquired to identify key white matter tracts for surgical avoidance. Here, we investigate whether structural connectivity abnormalities, inferred from dMRI, may be used in conjunction with functional iEEG abnormalities to aid localisation and resection of the epileptogenic zone (EZ), and improve surgical outcomes in epilepsy. We retrospectively investigated data from 43 patients with epilepsy who had surgery following iEEG. Twenty five patients (58%) were free from disabling seizures (ILAE 1 or 2) at one year. For all patients, T1-weighted and diffusion-weighted MRIs were acquired prior to iEEG implantation. Interictal iEEG functional, and dMRI structural connectivity abnormalities were quantified by comparison to a normative map and healthy controls respectively. First, we explored whether the resection of maximal (dMRI and iEEG) abnormalities related to improved surgical outcomes. Second, we investigated whether the modalities provided complementary information for improved prediction of surgical outcome. Third, we suggest how dMRI abnormalities may be useful to inform the placement of iEEG electrodes as part of the pre-surgical evaluation using a patient case study. Seizure freedom was 15 times more likely in those patients with resection of maximal dMRI and iEEG abnormalities (p=0.008). Both modalities were separately able to distinguish patient outcome groups and when combined, a decision tree correctly separated 36 out of 43 (84%) patients based on surgical outcome. Structural dMRI could be used in pre-surgical evaluations, particularly when localisation of the EZ is uncertain, to inform personalised iEEG implantation and resection.
Comment: 5 figures

الوصول الحر: http://arxiv.org/abs/2304.03192Test

المؤلفون: Wang, Yujiang, Schroeder, Gabrielle M, Horsley, Jonathan J, Panagiotopoulou, Mariella, Chowdhury, Fahmida A, Diehl, Beate, Duncan, John S, McEvoy, Andrew W, Miserocchi, Anna, de Tisi, Jane, Taylor, Peter N

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: Objective: Identifying abnormalities in interictal intracranial EEG, by comparing patient data to a normative map, has shown promise for the localisation of epileptogenic tissue and prediction of outcome. The approach typically uses short interictal segments of around one minute. However, the temporal stability of findings has not been established. Methods: Here, we generated a normative map of iEEG in non-pathological brain tissue from 249 patients. We computed regional band power abnormalities in a separate cohort of 39 patients for the duration of their monitoring period (0.92-8.62 days of iEEG data, mean 4.58 days per patient, over 4,800 hours recording). To assess the localising value of band power abnormality, we computed DRS - a measure of how different the surgically resected and spared tissue were in terms of band power abnormalities - over time. Results: In each patient, band power abnormality was relatively consistent over time. The median DRS of the entire recording period separated seizure free (ILAE = 1) and not seizure free (ILAE > 1) patients well (AUC = 0.69). This effect was similar interictally (AUC = 0.69) and peri-ictally (AUC = 0.71). Significance: Our results suggest that band power abnormality DRS, as a predictor of outcomes from epilepsy surgery, is a relatively robust metric over time. These findings add further support for abnormality mapping of neurophysiology data during presurgical evaluation.

الوصول الحر: http://arxiv.org/abs/2302.05734Test

المؤلفون: Elmalem, Michael S., Moody, Hanna, Ruffle, James K., de Schotten, Michel Thiebaut, Haggard, Patrick, Diehl, Beate, Nachev, Parashkev, Jha, Ashwani

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition

الوصف: The distributed nature of the neural substrate, and the difficulty of establishing necessity from correlative data, combine to render the mapping of brain function a far harder task than it seems. Methods capable of combining connective anatomical information with focal disruption of function are needed to disambiguate local from global neural dependence, and critical from merely coincidental activity. Here we present a comprehensive framework for focal and connective spatial inference based on sparse disruptive data, and demonstrate its application in the context of transient direct electrical stimulation of the human medial frontal wall during the pre-surgical evaluation of patients with focal epilepsy. Our framework formalizes voxel-wise mass-univariate inference on sparsely sampled data within the statistical parametric mapping framework, encompassing the analysis of distributed maps defined by any criterion of connectivity. Applied to the medial frontal wall, this transient dysconnectome approach reveals marked discrepancies between local and distributed associations of major categories of motor and sensory behaviour, revealing differentiation by remote connectivity to which purely local analysis is blind. Our framework enables disruptive mapping of the human brain based on sparsely sampled data with minimal spatial assumptions, good statistical efficiency, flexible model formulation, and explicit comparison of local and distributed effects.

الوصول الحر: http://arxiv.org/abs/2211.00393Test