Fast backward singular value decomposition (SVD) algorithm for magnetocardiographic signal reconstruction from pulsed atomic magnetometer data

Bai, Mingzhu; Huang, Yuxiang; Zhang, Guiying; Zheng, Wenqiang; Lin, Qiang; Hu, Zhenghui

doi:10.1364/oe.27.029534

Cited by 5 publications

(2 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To test/support our hypothesis, we conducted tPBM and sham experiments concurrently with 64-channel EEG recordings before, during, and after the tPBM/sham stimulation on 44 healthy human participants ( Wang et al, 2016 , 2017 ). After implementing the gSVD approach ( Harner, 1990 ; Bai et al, 2019 ), we were able to recognize or characterize 11 most-weighted, two-dimensional (2D) principal components (PCs) from the gSVD outputs and considered them as dominant EEG brain networks based on minimal temporal correlations among any of them. By performing eLORETA ( Jatoi et al, 2014 ; Imperatori et al, 2015 ; Ikeda et al, 2019 ) on these 2D topographies of gSVD-derived brain networks, we further achieved three-dimensional (3D) cortical source locations for each network.…”

Section: Introductionmentioning

confidence: 99%

Combination of Group Singular Value Decomposition and eLORETA Identifies Human EEG Networks and Responses to Transcranial Photobiomodulation

Wang

Wanniarachchi

et al. 2022

Front. Hum. Neurosci.

View full text Add to dashboard Cite

Transcranial Photobiomodulation (tPBM) has demonstrated its ability to alter electrophysiological activity in the human brain. However, it is unclear how tPBM modulates brain electroencephalogram (EEG) networks and is related to human cognition. In this study, we recorded 64-channel EEG from 44 healthy humans before, during, and after 8-min, right-forehead, 1,064-nm tPBM or sham stimulation with an irradiance of 257 mW/cm2. In data processing, a novel methodology by combining group singular value decomposition (gSVD) with the exact low-resolution brain electromagnetic tomography (eLORETA) was implemented and performed on the 64-channel noise-free EEG time series. The gSVD+eLORETA algorithm produced 11 gSVD-derived principal components (PCs) projected in the 2D sensor and 3D source domain/space. These 11 PCs took more than 70% weight of the entire EEG signals and were justified as 11 EEG brain networks. Finally, baseline-normalized power changes of each EEG brain network in each EEG frequency band (delta, theta, alpha, beta and gamma) were quantified during the first 4-min, second 4-min, and post tPBM/sham periods, followed by comparisons of frequency-specific power changes between tPBM and sham conditions. Our results showed that tPBM-induced increases in alpha powers occurred at default mode network, executive control network, frontal parietal network and lateral visual network. Moreover, the ability to decompose EEG signals into individual, independent brain networks facilitated to better visualize significant decreases in gamma power by tPBM. Many similarities were found between the cortical locations of SVD-revealed EEG networks and fMRI-identified resting-state networks. This consistency may shed light on mechanistic associations between tPBM-modulated brain networks and improved cognition outcomes.

show abstract

Section: Introductionmentioning

confidence: 99%

Combination of Group Singular Value Decomposition and eLORETA Identifies Human EEG Networks and Responses to Transcranial Photobiomodulation

Wang

Wanniarachchi

et al. 2022

Front. Hum. Neurosci.

View full text Add to dashboard Cite

show abstract

“…Taking into account the 5 cm separation between the two cells, the gradiometer sensitivity is better than 18 fT/cm/√Hz. Combined with the bandwidth of over 100 Hz, the intrinsic gradiometer can be used for many applications such as nondestructive evaluation [19], unexplode ordnance (UXO) detection [20] and magnetocardiography (MCG) in an unshielded environment [21,22,23,24]. Here we demonstrate the MCG application in an office environment.…”

mentioning

confidence: 98%

Portable intrinsic gradiometer for ultra-sensitive detection of magnetic gradient in unshielded environment

Zhang¹,

Mhaskar²,

Smith³

et al. 2020

Applied Physics Letters

View full text Add to dashboard Cite

We demonstrate a portable intrinsic scalar magnetic gradiometer composed of miniaturized cesium vapor cells and verticalcavity surface-emitting lasers (VCSELs). Two cells, with an inner dimension of 5 mm x 5 mm x 5 mm and separated by 5 cm, are driven by one VCSEL and the resulting Larmor precessions are probed by a second VCSEL through optical rotation. The off-resonant linearly polarized probe light interrogates two cells at the same time and directly reads out the amplitude difference between magnetic fields at two cell locations. The intrinsic gradiometer scheme has the advantage of avoiding added noise from combining two scalar magnetometers. We achieve better than 18 fT/cm/√Hz sensitivity in the gradient measurement. Ultra-sensitive short-baseline magnetic gradiometers can potentially play an important role in many practical applications, such as nondestructive evaluation and unexplode ordnance (UXO) detection. Another application of the gradiometer is for magnetocardiography (MCG) in an unshielded environment. Real-time MCG signals can be extracted from the raw gradiometer readings. The intrinsic gradiometer greatly simplifies the MCG setup and may lead to ubiquitous MCG measurement in the future.Over the last two decades, many breakthroughs have been achieved in atomic magnetometer research. For example, the discovery of the spin-exchange relaxation-free (SERF) phenomenon at high atomic density and low magnetic field leads to a great improvement in the magnetometer noise performance [1]. Sensitivities comparable with [2] or even outperforming [3] those of superconducting quantum interference devices (SQUIDs) have been reported with SERF magnetometers. Another example is the successful fabrication of atomic magnetometers using the technique of Micro-Electro-Mechanical Systems (MEMS) [4,5,6,7,8]. MEMS techniques enable chip-scale devices, significantly reducing size and power-consumption of atomic magnetometers. Chip-scale magnetometers can have sizes approaching 10 mm 3 and dissipate less than 200 mW. Despite all these advances, applications of atomic magnetometers are still limited. Highly sensitive SERF magnetometers require a magnetically shielded environment while chip-scale total-field magnetometers have subpar noise performances [5], although a scalar magnetometer with a sensitivity of 100 fT/√Hz has been demonstrated using a MEMS-based cesium vapor cell [9]. With bigger cells, scalar magnetometers can reach sensitivities of sub-10 fT/√Hz [10] or even sub-fT/√Hz [11]. In practical applications in an unshielded environment, the output noise of scalar magnetometers is often dominated by the background field fluctuation, instead of their fundamental sensitivities. To overcome this problem, a common solution is to set up a gradiometer system using two or more magnetometers [12,13,14]. By taking the reading difference between adjacent magnetometers, this conventional gradiometer configuration suppresses the common field fluctuations at the cost of worsening the fundamental sensitivity by at least a factor...

show abstract

Portable Magnetometry for Detection of Biomagnetism in Ambient Environments

et al. 2020

View full text Add to dashboard Cite

Fast backward singular value decomposition (SVD) algorithm for magnetocardiographic signal reconstruction from pulsed atomic magnetometer data

Cited by 5 publications

References 23 publications

Combination of Group Singular Value Decomposition and eLORETA Identifies Human EEG Networks and Responses to Transcranial Photobiomodulation

Combination of Group Singular Value Decomposition and eLORETA Identifies Human EEG Networks and Responses to Transcranial Photobiomodulation

Portable intrinsic gradiometer for ultra-sensitive detection of magnetic gradient in unshielded environment

Portable Magnetometry for Detection of Biomagnetism in Ambient Environments

Contact Info

Product

Resources

About