In recent years the study of resting state brain networks (RSNs) has become an important area neuroimaging. The majority studies have used functional magnetic resonance imaging (fMRI) to measure temporal correlation between blood-oxygenation-level–dependent (BOLD) signals from different areas. However, BOLD is indirect related hemodynamics, and electrophysiological basis connectivity spatially separate network nodes cannot be comprehensively assessed using this technique. paper we describe a...

To provide an effective substrate for cognitive processes, functional brain networks should be able to reorganize and coordinate on a sub-second temporal scale. We used magnetoencephalography recordings of spontaneous activity characterize whole-brain connectivity dynamics at high resolution. Using novel approach that identifies the points in time which unique patterns recur, we reveal transient (100-200 ms) states with spatial topographies similar those well-known resting state networks. By...

Functional connectivity (FC) between brain regions is thought to be central the way in which processes information. Abnormal implicated a number of diseases. The ability study FC therefore key goal for neuroimaging. (fc) MRI has become popular tool make measurements but technique limited by its indirect nature. A multimodal approach an attractive means investigate electrodynamic mechanisms underlying hemodynamic connectivity. In this paper, we resting state using fcMRI and...

Ambiguities in the source reconstruction of magnetoencephalographic (MEG) measurements can cause spurious correlations between estimated time-courses. In this paper, we propose a symmetric orthogonalisation method to correct for these artificial set multiple regions interest (ROIs). This process enables straightforward application network modelling methods, including partial correlation or multivariate autoregressive modelling, infer connectomes, functional networks, from corrected ROIs....

Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded healthy human participants with magnetoencephalography after intravenous infusion of psilocybin—prodrug nonselective serotonin 2A receptor agonist classic psychedelic psilocin. Psilocybin reduced spontaneous cortical power from 1 to 50 Hz posterior association cortices, 8 100 frontal cortices. Large...

MEG offers dynamic and spectral resolution for resting-state connectivity which is unavailable in fMRI. However, there are a wide range of available network estimation methods MEG, little the way existing guidance on ones to employ. In this technical note, we investigate extent many popular measures stationary suitable use localising magnetic sources with scalar beamformer. We as empirical criteria that individual subjects should be repeatable, group-level shows good reproducibility. Using...

Advances in the field of quantum sensing mean that magnetic sensors, operating at room temperature, are now able to achieve sensitivity similar cryogenically cooled devices (SQUIDs). This means temperature magnetoencephalography (MEG), with a greatly increased flexibility sensor placement can be considered. Further, these new sensors placed directly on scalp surface giving, theoretically, large increase magnitude measured signal. Here, we present recordings made using single optically-pumped...

A number of recent studies have begun to show the promise magnetoencephalography (MEG) as a means non-invasively measure functional connectivity within distributed networks in human brain. However, problems with methodology still remain — biggest these being how deal non-independence voxels source space, often termed signal leakage. In this paper we demonstrate method by which non-zero lag cortico-cortical interactions between power envelopes neural oscillatory processes can be reliably...

Frequency-specific oscillations and phase-coupling of neuronal populations are essential mechanisms for the coordination activity between brain areas during cognitive tasks. Therefore, ongoing ascribed to different functional networks should also be able reorganise coordinate via similar mechanisms. We develop a novel method identifying large-scale phase-coupled network dynamics show that resting in magnetoencephalography well characterised by visits short-lived transient states, with...

When combined with source modeling, magneto- (MEG) and electroencephalography (EEG) can be used to study long-range interactions among cortical processes non-invasively. Estimation of such inter-areal connectivity is nevertheless hindered by instantaneous field spread volume conduction, which artificially introduce linear correlations impair separability in current estimates. To overcome the inflating effects mixing inherent standard interaction measures, alternative phase-...

Magnetoencephalography (MEG) is a powerful technique for functional neuroimaging, offering non-invasive window on brain electrophysiology. MEG systems have traditionally been based cryogenic sensors which detect the small extracranial magnetic fields generated by synchronised current in neuronal assemblies, however, such fundamental limitations. In recent years, non-cryogenic quantum-enabled sensors, called optically-pumped magnetometers (OPMs), combination with novel techniques accurate...

Recent years have shown the critical importance of inter-regional neural network connectivity in supporting healthy brain function. Such is measurable using neuroimaging techniques such as MEG, however richness electrophysiological signal makes gaining a complete picture challenging. Specifically, can be calculated statistical interdependencies between oscillations within large range different frequency bands. Further, computed This pan-spectral hierarchy likely helps to mediate simultaneous...

Small, commercially-available Optically Pumped Magnetometers (OPMs) can be used to construct a wearable Magnetoencephalography (MEG) system that allows large head movements made during recording. The small dynamic range of these sensors however means movement in the residual static magnetic field found inside typical Magnetically Shielded Rooms (MSRs) saturate sensor outputs, rendering data unusable. This problem ameliorated by using set electromagnetic coils attenuate spatially-varying...

Magnetoencephalography (MEG) is a sophisticated tool which yields rich information on the spatial, spectral and temporal signatures of human brain function. Despite unique potential, MEG limited by low signal-to-noise ratio (SNR) caused both inherently small magnetic fields generated brain, scalp-to-sensor distance. The latter in current systems due to requirement for pickup coils be cryogenically cooled. Recent work suggests that optically-pumped magnetometers (OPMs) might viable...

Optically-pumped magnetometers (OPMs) are an established alternative to superconducting sensors for magnetoencephalography (MEG), offering significant advantages including flexibility accommodate any head size, uniform coverage, free movement during scanning, better data quality and lower cost. However, OPM sensor technology remains under development; there is regarding design it not yet clear which variant will prove most effective MEG. Most OPM-MEG implementations have either used...

The optically pumped magnetometer (OPM) is a viable means to detect magnetic fields generated by human brain activity. Compared conventional detectors (superconducting quantum interference devices) OPMs are small, lightweight, flexible, and operate without cryogenics. This has led step change in instrumentation for magnetoencephalography (MEG), enabling "wearable" scanner platform, adaptable fit any head size, able acquire data whilst subjects move, offering improved quality. Although many...

We present both a scientific overview and conceptual positions concerning the challenges assets of electrophysiological measurements in search for nature functions human connectome. discuss how field has been inspired by findings approaches from functional magnetic resonance imaging (fMRI) informed small number significant multimodal empirical studies, which show that canonical networks are commonplace fMRI fact rooted processes. This review is also an opportunity to produce brief,...

Optically-pumped magnetometers (OPMs) offer the potential for a step change in magnetoencephalography (MEG) enabling wearable systems that provide improved data quality, accommodate any subject group, allow capture during movement and potentially reduce cost. However, OPM-MEG is nascent technology and, to realise its potential, it must be shown facilitate key neuroscientific measurements, such as characterisation of brain networks. Networks, connectivities underlie them, have become core...

Background Magnetoencephalography (MEG) is an established method used to detect and localize focal interictal epileptiform discharges (IEDs). Current MEG systems house hundreds of cryogenic sensors in a rigid, one-size-fits-all helmet, which results several limitations, particularly children. Purpose To determine if on-scalp based on optically pumped magnetometers (OPMs) alleviates the main limitations MEG. Materials Methods In this prospective single-center study conducted tertiary...

Optically pumped magnetometers (OPMs) are an emerging lightweight and compact sensor that can measure magnetic fields generated by the human brain. OPMs enable construction of wearable magnetoencephalography (MEG) systems, which offer advantages over conventional instrumentation. However, when trying to signals at low frequency, higher levels inherent noise, interference movement artefact introduce a significant challenge. Accurate characterisation frequency brain is important for...