Dataset Information

Shared and distinct global signal topography disturbances in subcortical and cortical networks in human epilepsy.

ABSTRACT: Epilepsy is a common brain network disorder associated with disrupted large-scale excitatory and inhibitory neural interactions. Recent resting-state fMRI evidence indicates that global signal (GS) fluctuations that have commonly been ignored are linked to neural activity. However, the mechanisms underlying the altered global pattern of fMRI spontaneous fluctuations in epilepsy remain unclear. Here, we quantified GS topography using beta weights obtained from a multiple regression model in a large group of epilepsy with different subtypes (98 focal temporal epilepsy; 116 generalized epilepsy) and healthy population (n = 151). We revealed that the nonuniformly distributed GS topography across association and sensory areas in healthy controls was significantly shifted in patients. Particularly, such shifts of GS topography disturbances were more widespread and bilaterally distributed in the midbrain, cerebellum, visual cortex, and medial and orbital cortex in generalized epilepsy, whereas in focal temporal epilepsy, these networks spread beyond the temporal areas but mainly remain lateralized. Moreover, we found that these abnormal GS topography patterns were likely to evolve over the course of a longer epilepsy disease. Our study demonstrates that epileptic processes can potentially affect global excitation/inhibition balance and shift the normal GS topological distribution. These progressive topographical GS disturbances in subcortical-cortical networks may underlie pathophysiological mechanisms of global fluctuations in human epilepsy.

SUBMITTER: Li R

PROVIDER: S-EPMC7776006 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Shared and distinct global signal topography disturbances in subcortical and cortical networks in human epilepsy.

Li Rong R Wang Hongyu H Wang Liangcheng L Zhang Leiyao L Zou Ting T Wang Xuyang X Liao Wei W Zhang Zhiqiang Z Lu Guangming G Chen Huafu H

Human brain mapping 20201019 2

Epilepsy is a common brain network disorder associated with disrupted large-scale excitatory and inhibitory neural interactions. Recent resting-state fMRI evidence indicates that global signal (GS) fluctuations that have commonly been ignored are linked to neural activity. However, the mechanisms underlying the altered global pattern of fMRI spontaneous fluctuations in epilepsy remain unclear. Here, we quantified GS topography using beta weights obtained from a multiple regression model in a lar ...[more]

PMID: 33073893

Similar Datasets

Project description:Using a hypothesis-driven approach, subcortical and cortical regions implicated in anxiety disorders in the general population were examined in children with recent-onset epilepsy with versus without anxiety compared to controls. This study reports frequency of anxiety disorders while examining familial, clinical, and demographic variables associated with anxiety in children with epilepsy.Participants included 88 children with epilepsy aged 8-18 years: 25 with a current anxiety disorder and 63 children with epilepsy and no current anxiety disorder. Forty-nine controls without anxiety disorders were included. T1 volumetric magnetic resonance imaging (MRI) scans were collected; subcortical volumes and cortical thickness were computed using the FreeSurfer image analysis suite. Analyses focused on adjusted measures of subcortical volumes and cortical thickness.Relative to controls, larger left amygdala volumes were found in the Epilepsy with Anxiety group compared to the Epilepsy without Anxiety group (p = 0.027). In the hippocampus, there were no significant differences between groups. Examination of cortical thickness demonstrated that the Epilepsy with Anxiety group showed thinning in left medial orbitofrontal (p = 0.001), right lateral orbitofrontal (p = 0.017), and right frontal pole (p = 0.009). There were no differences between groups in age, sex, IQ, age of onset, medications, or duration of epilepsy. There were more family members with a history of anxiety disorders in the Epilepsy with Anxiety group compared to the Epilepsy without Anxiety group (p = 0.005).Anxiety is a common psychiatric comorbidity in children with recent-onset epilepsy with volumetric enlargement of the amygdala and thinner cortex in orbital and other regions of prefrontal cortex, suggesting structural abnormalities in brain regions that are part of the dysfunctional networks reported in individuals with anxiety disorders in the general population. These findings are evident early in the course of epilepsy, are not related to chronicity of seizures, and may be linked to a family history of anxiety and depressive disorders.

Project description:Abstract Epilepsy in infancy links to a significant risk of neurodevelopmental delay, calling for a better understanding of its underlying mechanisms. Here, we studied cortical activity networks in infants with early-onset epilepsy to identify network properties that could pre-empt infants’ neurodevelopmental course. We studied high-density (64 channel) electroencephalogram during non-rapid eye movement (N2) sleep in n = 49 infants at 1 year of age after being diagnosed with epilepsy during their first year of life. We computed frequency-specific networks in the cortical source space for two intrinsic brain modes: amplitude–amplitude and phase–phase correlations. Cortical activity networks of all frequency bands and connectivity modes were compared between the syndrome groups as well as between the three categories of neurocognitive development. The group differences were studied at three spatial levels: global, regional, and individual connections. Cortical mechanisms related to infant epilepsy were further compared with physiological networks using an automatic spindle detection algorithm. Our results show that global connectivity does not significantly differ between epilepsy syndromes; however, it co-varies with neurocognitive development. The largest network differences were observed at the lowest (<1 Hz) and mid-range (10–15 Hz) frequency bands. An algorithmic removal of sleep spindles from the data partially reduced the mid-range frequency network’s strength. The centrocentral and frontocentral networks at the spindle frequencies were found to be strongest in infants with a persistent age-typical neurocognitive performance, while their low-frequency (< 1 Hz) networks were weaker for both amplitude-amplitude [P = 0.008, effect size = 0.61] and phase–phase correlations (P = 0.02, effect size = 0.54) at low (< 1 Hz). However, subjects with persistent mild neurocognitive delay from 1 to 2 years of age had higher amplitude–amplitude (P = 0.02, effect size = 0.73) and phase–phase (P = 0.06, effect size = 0.59) at low frequencies than those that deteriorated from mild to severely delayed from 1 to 2 years of age. Our findings suggest that cortical activity networks reflect the underlying clinical course of infants’ epilepsy, and measures of spectrally and spatially resolved networks might become useful in better understanding infantile epilepsy as a network disease. Auno et al. report that cortical activity networks examined from the scalp electroencephalogram provide a sensitive measure of brain function. Infants with epilepsy exhibited specific network changes that link to the severity of both current and upcoming neurological outcomes. They may be used for guiding early interventions in infants with epilepsy. Graphical Abstract Graphical abstract

Project description:Generalized tonic-clonic seizures are among the most dramatic physiological events in the nervous system. The brain regions involved during partial seizures with secondary generalization have not been thoroughly investigated in humans. We used single photon emission computed tomography (SPECT) to image cerebral blood flow (CBF) changes in 59 secondarily generalized seizures from 53 patients. Images were analysed using statistical parametric mapping to detect cortical and subcortical regions most commonly affected in three different time periods: (i) during the partial seizure phase prior to generalization; (ii) during the generalization period; and (iii) post-ictally. We found that in the pre-generalization period, there were focal CBF increases in the temporal lobe on group analysis, reflecting the most common region of partial seizure onset. During generalization, individual patients had focal CBF increases in variable regions of the cerebral cortex. Group analysis during generalization revealed that the most consistent increase occurred in the superior medial cerebellum, thalamus and basal ganglia. Post-ictally, there was a marked progressive CBF increase in the cerebellum which spread to involve the bilateral lateral cerebellar hemispheres, as well as CBF increases in the midbrain and basal ganglia. CBF decreases were seen in the fronto-parietal association cortex, precuneus and cingulate gyrus during and following seizures, similar to the 'default mode' regions reported previously to show decreased activity in seizures and in normal behavioural tasks. Analysis of patient behaviour during and following seizures showed impaired consciousness at the time of SPECT tracer injections. Correlation analysis across patients demonstrated that cerebellar CBF increases were related to increases in the upper brainstem and thalamus, and to decreases in the fronto-parietal association cortex. These results reveal a network of cortical and subcortical structures that are most consistently involved in secondarily generalized tonic-clonic seizures. Abnormal increased activity in subcortical structures (cerebellum, basal ganglia, brainstem and thalamus), along with decreased activity in the association cortex may be crucial for motor manifestations and for impaired consciousness in tonic-clonic seizures. Understanding the networks involved in generalized tonic-clonic seizures can provide insights into mechanisms of behavioural changes, and may elucidate targets for improved therapies.

Dataset Information

Shared and distinct global signal topography disturbances in subcortical and cortical networks in human epilepsy.

Publications

Shared and distinct global signal topography disturbances in subcortical and cortical networks in human epilepsy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets