A5028809526- Functional Brain Connectivity Studies
- Atomic and Subatomic Physics Research
- Advanced MRI Techniques and Applications
- EEG and Brain-Computer Interfaces
- Non-Invasive Vital Sign Monitoring
- Neural dynamics and brain function
- Muscle activation and electromyography studies
- Electrical and Bioimpedance Tomography
- Epilepsy research and treatment
- Magnetic and transport properties of perovskites and related materials
- Magnetic Field Sensors Techniques
- Acoustic Wave Resonator Technologies
- Quantum optics and atomic interactions
- Gaze Tracking and Assistive Technology
- Cerebral Venous Sinus Thrombosis
- Advanced X-ray and CT Imaging
- Hearing Loss and Rehabilitation
- Motor Control and Adaptation
- Context-Aware Activity Recognition Systems
- Glaucoma and retinal disorders
- Brain Tumor Detection and Classification
- Heart Rate Variability and Autonomic Control
- Medical Imaging Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Radiomics and Machine Learning in Medical Imaging
University College London
2019-2025
Universitätsklinik Balgrist
2024-2025
University of Zurich
2024-2025
Institute for Biomedical Engineering
2024-2025
ETH Zurich
2024-2025
National Hospital for Neurology and Neurosurgery
2019-2025
Wellcome Centre for Human Neuroimaging
2019-2024
University College Lahore
2023
Statistical Parametric Mapping (SPM) is an integrated set of methods for testing hypotheses about the brain's structure and function, using data from imaging devices. These are implemented in open source software package, SPM, which has been continuous development more than 30 years by international community developers. This paper reports release SPM 25.01, a major new version that incorporates novel analysis methods, optimisations existing as well improved practices science development.
To allow wearable magnetoencephalography (MEG) recordings to be made on unconstrained subjects the spatially inhomogeneous remnant magnetic field inside magnetically shielded room (MSR) must nulled. Previously, a large bi-planar coil system which produces uniform fields and gradients was used for this purpose. Its construction presented significant challenge, six distinct coils were wound two 1.6 × m2 planes. Here, we exploit shared symmetries produce simultaneously optimised generate...
Traditional magnetoencephalographic (MEG) brain imaging scanners consist of a rigid sensor array surrounding the head; this means that they are maximally sensitive to superficial structures. New technology based on optical pumping we can now consider more flexible and creative placement. Here explored magnetic fields generated by model human hippocampus not only across scalp but also at roof mouth. We found simulated hippocampal sources gave rise dipolar field patterns with one surface...
Here we propose that much of the magnetic interference observed when using optically pumped magnetometers for MEG experiments can be modeled as a spatially homogeneous field. We show this approximation reduces sensor level variance and substantially improves statistical power. This model does not require knowledge underlying neuroanatomy nor positions. It only needs information about orientation. Due to model's low rank there is little risk removing substantial neural signal. However,...
Optically pumped magnetometer-based magnetoencephalography (OP-MEG) can be used to measure neuromagnetic fields while participants move in a magnetically shielded room. Head movements previous OP-MEG studies have been up 20 cm translation and ∼30° rotation sitting position. While this represents step-change over stationary MEG systems, naturalistic head movement is likely exceed these limits, particularly when are standing up. In proof-of-concept study, we sought push the limits of even...
Magnetically shielded rooms (MSRs) use multiple layers of materials such as MuMetal to screen external magnetic fields that would otherwise interfere with high precision field measurements magnetoencephalography (MEG). Optically pumped magnetometers (OPMs) have enabled the development wearable MEG systems which potential provide a motion tolerant functional brain imaging system spatiotemporal resolution. Despite significant promise, OPMs impose stringent shielding requirements, operating...
One of the primary technical challenges facing magnetoencephalography (MEG) is that magnitude neuromagnetic fields several orders lower than interfering signals. Recently, a new type sensor has been developed - optically pumped magnetometer (OPM). These sensors can be placed directly on scalp and move with head during participant movement, making them wearable. This opens up range exciting experimental clinical opportunities for OPM-based MEG experiments, including paediatric studies,...
Abstract We demonstrate the first use of Optically Pumped Magnetoencephalography (OP‐MEG) in an epilepsy patient with unrestricted head movement. Current clinical MEG uses a traditional SQUID system, where sensors are cryogenically cooled and housed helmet which patient’s is fixed. Here, we different type sensor (OPM), operates at room temperature can be placed directly on scalp, permitting free performed OP‐MEG recording refractory focal epilepsy. OP‐MEG‐identified analogous interictal...
In this study we explore the interference rejection and spatial sampling properties of multi-axis Optically Pumped Magnetometer (OPM) data. We use both vector spherical harmonics eigenspectra to quantify how well an array can separate neuronal signal from environmental while adequately entire cortex. found that triaxial OPMs have superb noise allowing for very high orders (L=6) be accounted minimally affecting neural space (2dB attenuation a 60-sensor system). show at least 11th order (143...
Most neuroimaging techniques require the participant to remain still for reliable recordings be made. Optically pumped magnetometer (OPM) based magnetoencephalography (OP-MEG) however, is a technique which can used measure neural signals during large movement (approximately 1 m) within magnetically shielded room (MSR) (Boto et al., 2018; Seymour 2021). Nevertheless, environmental magnetic fields vary both spatially and temporally OPMs only operate limited field range, constrains movement....
Abstract Multipole expansions have been used extensively in the Magnetoencephalography (MEG) literature for mitigating environmental interference and modelling brain signal. However, their application to Optically Pumped Magnetometer (OPM) data is challenging due wide variety of existing OPM sensor array designs. We therefore explore how such multipole models can be adapted provide stable signal across systems. Firstly, we demonstrate prolate spheroidal (rather than spherical) harmonics a...
Optically pumped magnetometers (OPMs) have made moving, wearable magnetoencephalography (MEG) possible. The OPMs typically used for MEG require a low background magnetic field to operate, which is achieved using both passive and active shielding. However, the never truly zero Tesla, so at each of changes as participant moves. This leads position orientation dependent in measurements, manifest frequency artefacts data.
Abstract Voluntary human movement relies on interactions between the spinal cord, brain, and sensory afferents. The integrative function of cord has proven particularly difficult to study directly non-invasively in humans due challenges measuring activity. Investigations sensorimotor integration often rely cortico-muscular coupling, which can capture brain muscle, but cannot reveal how mediates this communication. Here, we introduce a system for direct, non-invasive imaging concurrent...
Non-invasive spatiotemporal imaging of brain activity during large-scale, whole body movement is a significant methodological challenge for the field neuroscience. Here, we present dataset recorded using new modality, optically-pumped magnetoencephalography (OP-MEG), to record human stepping. Participants (n=3) performed visually guided stepping task requiring precise foot placement while dual-axis and triaxial OP-MEG leg muscle (electromyography, EMG) were recorded. The also includes...
Abstract Neuroimaging studies have typically relied on rigorously controlled experimental paradigms to probe cognition, in which movement is restricted, primitive, an afterthought or merely used indicate a subject’s choice. Whilst powerful, these do not often resemble how we behave everyday life, so new generation of ecologically valid experiments are being developed. Magnetoencephalography (MEG) measures neural activity by sensing extracranial magnetic fields. It has recently been...
ABSTRACT When working with sensor‐level data recorded using on‐scalp neuroimaging methods such as electroencephalography (EEG), it is common practice to use two‐dimensional (2D) representations of sensor positions aid interpretation. Positioning sensors relative anatomy, in the classic 10–20 system EEG electrode placement, enables 2D topographies that are familiar many researchers and clinicians. However, when another increasingly popular method, optically pumped magnetometer–based...
Abstract Several new technologies have emerged promising Magnetoencephalography (MEG) systems in which the sensors can be placed close to scalp. One such technology, Optically Pumped MEG (OP-MEG) allows for a scalp mounted system that provides measurements within millimetres of surface. A question arises developing on-scalp is: how many are necessary achieve adequate performance/spatial discrimination? There factors consider answering this as signal noise ratio (SNR), locations and depths...
Abstract Background Optically pumped magnetometers (OPMs) have made moving, wearable magnetoencephalography (MEG) possible. The OPMs typically used for MEG require a low background magnetic field to operate, which is achieved using both passive and active shielding. However, the never truly zero Tesla, so at each of changes as participant moves. This leads position orientation dependent in measurements, manifest frequency artefacts data. Objective We modelled spatial variation model predict...
When planning for epilepsy surgery, multiple potential sites resection may be identified through anatomical imaging. Magnetoencephalography (MEG) using optically pumped sensors (OP-MEG) is a non-invasive functional neuroimaging technique which could used to help identify the epileptogenic zone from these candidate regions. Here we test utility of a-priori information imaging differentiating lesion with OP-MEG. We investigate number scenarios: whether use rigid or flexible sensor arrays,...
Non-invasive imaging of the human spinal cord is a vital tool for understanding mechanisms underlying its functions in both healthy and pathological conditions. However, non-invasive presents significant methodological challenge because difficult to access with conventional neurophysiological approaches, due proximity other organs muscles, as well physiological movements caused by respiration, heartbeats, cerebrospinal fluid (CSF) flow. Here, we discuss present state future directions...
Neuroimaging studies have typically relied on rigorously controlled experimental paradigms to probe cognition, in which movement is restricted, primitive, an afterthought or merely used indicate a subject's choice. Whilst powerful, these do not often resemble how we behave everyday life, so new generation of ecologically valid experiments are being developed. Magnetoencephalography (MEG) measures neural activity by sensing extracranial magnetic fields. It has recently been transformed from...
Abstract Beamforming is one of the most commonly used source reconstruction methods for magneto- and electroencephalography (M/EEG). One underlying assumption, however, that distant sources are uncorrelated here we tested whether this an appropriate model human hippocampal data. We revised Empirical Bayesian Beamfomer (EBB) to accommodate specific a-priori correlated models. showed in simulation could use evidence (as approximated by Free Energy) distinguish between different scenarios....
Abstract Several new technologies have recently emerged promising MEG systems in which the sensors can be placed close to scalp. One such technology, Optically Pumped Magnetometry (OP-MEG) allows for a scalp mounted flexible system that provides field measurements within mm of surface. A question arises developing on-scalp systems, as OP-MEG scanners, is: how many are necessary achieve adequate performance/spatial discrimination? There factors consider answering this signal noise ratio...
Optically pumped magnetometers have opened many possibilities for the study of human brain function using wearable moveable technology. In order to fully exploit this capability, a stable low-field environment at sensors is required. One way achieve predict (and compensate for) changes in ambient magnetic field as subject moves through room. The ultimate aim account dynamically changing noise environments by updating model based on measurements from moving sensor array. We begin...