Purpose: To explore if background infraslow activity (ISA) can be retrieved from archived magnetoencephalographic (MEG) recordings and its potential clinical relevance.
Methods: Archived recordings of 15 patients with epilepsy and 10 normal subjects were evaluated for MEG/EEG delta (0.5-3 Hz) and ISA (0.01-0.1 Hz). The data were obtained on a Neuromag/Elekta system with 204 planar gradiometers and 102 magnetometer sensors and also 60 EEG channels. To remove artifacts, all MEG files were temporal signal space separation filtered. The data were then analyzed with the BESA Research software.
Results: Infraslow activity was present in all files for MEG and EEG. Good concordance between EEG and MEG ISA was seen with delta for laterality and with clinical features. Delta frequencies were always less than 2 Hz. During sleep, an inverse relationship between delta and ISA occurred. With increasing depth of sleep, delta activity increased while ISA decreased and vice versa. Intermittent higher amplitude transients, arising from background, were also seen but their nature is at present unknown. Clinically relevant ictal onset baseline shifts were likewise observed.
Conclusion: Infraslow activity is a normal segment of the cerebral electromagnetic frequency spectrum. It follows physiologic rules and can be related to areas of pathology. This is in accord with previously published EEG observations and further studies of this segment of the electromagnetic frequency spectrum for its origin and changes in health and disease are indicated.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1097/WNP.0000000000000246 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Rapid dynamics of electrophysiological connectome states are heritable.
Netw Neurosci
December 2024
Department of Psychology, University of Illinois Urbana-Champaign, Champaign, IL, USA.
Time-varying changes in whole-brain connectivity patterns, or connectome state dynamics, are a prominent feature of brain activity with broad functional implications. While infraslow (<0.1 Hz) connectome dynamics have been extensively studied with fMRI, rapid dynamics highly relevant for cognition are poorly understood.
View Article and Find Full Text PDFInfraslow noradrenergic locus coeruleus activity fluctuations are gatekeepers of the NREM-REM sleep cycle.
Nat Neurosci
November 2024
Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
The noradrenergic locus coeruleus (LC) regulates arousal levels during wakefulness, but its role in sleep remains unclear. Here, we show in mice that fluctuating LC neuronal activity partitions non-rapid-eye-movement sleep (NREMS) into two brain-autonomic states that govern the NREMS-REMS cycle over ~50-s periods; high LC activity induces a subcortical-autonomic arousal state that facilitates cortical microarousals, whereas low LC activity is required for NREMS-to-REMS transitions. This functional alternation regulates the duration of the NREMS-REMS cycle by setting permissive windows for REMS entries during undisturbed sleep while limiting these entries to maximally one per ~50-s period during REMS restriction.
View Article and Find Full Text PDFThe intrinsic propagation directionality of fMRI infra-slow activity during visual tasks.
Neuroscience
January 2025
Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea. Electronic address:
The temporal order of propagation in the blood-oxygen-level-dependent (BOLD) infra-slow activity (ISA, 0.01-0.1 Hz) of functional magnetic resonance imaging (fMRI) can indicate the functional organization of the brain.
View Article and Find Full Text PDFSleep deprivation leads to non-adaptive alterations in sleep microarchitecture and amyloid-β accumulation in a murine Alzheimer model.
Cell Rep
November 2024
Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA. Electronic address:
Article Synopsis
- Impaired sleep is common with aging and is linked to the onset of Alzheimer's disease; researchers studied the effects of sleep deprivation on both healthy mice and a mouse model of Alzheimer's.
- After sleep deprivation, both groups showed increased EEG slow-wave activity, but only healthy mice exhibited enhanced norepinephrine oscillations typical of good sleep.
- The Alzheimer’s model mice didn't show this enhancement 24 hours post-deprivation, along with a buildup of amyloid-β protein, suggesting that their disrupted sleep patterns may increase the risk of developing Alzheimer's.
Sex differences in the human brain related to visual motion perception.
Biol Sex Differ
November 2024
Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310029, China.
Article Synopsis
- - Previous research indicates that males can perceive visual motion direction more quickly than females, prompting an investigation into whether the middle temporal visual complex (MT+) is responsible for these differences in perception duration.
- - Using ultra-high field MRI, the study involved 95 participants to assess sex-related variations in brain structure and activity in the MT+ region, revealing that males have larger gray matter volume and enhanced spontaneous activity in the left MT+.
- - The results highlight significant sex differences in brain structure and function, specifically in the MT+ area, which are associated with motion perception abilities, suggesting that these neural characteristics may contribute to the different temporal thresholds for motion discrimination between genders.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!