Magnetoencephalography using high temperature rf SQUIDs

Zhang, Y.; Tavrin, Y.; Braginski, A. I.; Heiden, C.; Hampson, S.; Pantev, C.; Elbert, Thomas

doi:10.1007/bf01128694

Cited by 34 publications

(16 citation statements)

References 6 publications

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“…VI, the best high-T c SQUID magnetometers have a white noise below 10 fT Hz Ϫ1/2 , but at 1 Hz the noise is about a factor of 3 higher. Thus high-T c magnetometers are not yet quite good enough for clinical MEG, although there have been several demonstrations of neuromagnetic measurements (Zhang, Tavrin et al, 1993;DiIorio et al, 1995;Curio et al, 1996;. On the other hand, the requirements for magnetocardiology (MCG)-measurements of signals from the human heart-are somewhat more relaxed, and as a result most biomagnetic measurements with high-T c SQUIDs have focused on this application.…”

Section: A Biomagnetismmentioning

confidence: 99%

High-transition-temperature superconducting quantum interference devices

et al. 1999

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Section: A Biomagnetismmentioning

confidence: 99%

High-transition-temperature superconducting quantum interference devices

et al. 1999

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“…Two prominent and promising sensor technologies exist, high-critical-temperature (high- T c ) superconducting quantum interference devices (SQUIDs) [10–12] and optically pumped magnetometers (OPMs) [13,14]. High- T c sensors are superconducting at much higher temperatures (<90 K; 77 K is the typical operation temperature with liquid nitrogen cooling) than conventional low- T c sensors (< 9 K; 4 K is the typical operation temperature with liquid helium cooling).…”

Section: Introductionmentioning

confidence: 99%

Similarities and differences between on-scalp and conventional in-helmet magnetoencephalography recordings

et al. 2017

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The development of new magnetic sensor technologies that promise sensitivities approaching that of conventional MEG technology while operating at far lower operating temperatures has catalysed the growing field of on-scalp MEG. The feasibility of on-scalp MEG has been demonstrated via benchmarking of new sensor technologies performing neuromagnetic recordings in close proximity to the head surface against state-of-the-art in-helmet MEG sensor technology. However, earlier work has provided little information about how these two approaches compare, or about the reliability of observed differences. Herein, we present such a comparison, based on recordings of the N20m component of the somatosensory evoked field as elicited by electric median nerve stimulation. As expected from the proximity differences between the on-scalp and in-helmet sensors, the magnitude of the N20m activation as recorded with the on-scalp sensor was higher than that of the in-helmet sensors. The dipole pattern of the on-scalp recordings was also more spatially confined than that of the conventional recordings.Our results furthermore revealed unexpected temporal differences in the peak of the N20m component. An analysis protocol was therefore developed for assessing the reliability of this observed difference. We used this protocol to examine our findings in terms of differences in sensor sensitivity between the two types of MEG recordings. The measurements and subsequent analysis raised attention to the fact that great care has to be taken in measuring the field close to the zero-line crossing of the dipolar field, since it is heavily dependent on the orientation of sensors. Taken together, our findings provide reliable evidence that on-scalp and in-helmet sensors measure neural sources in mostly similar ways.

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“…Their resistively shunted junction (RSJ) characteristics were found to be very similar to those of single grain-boundary junctions [18,21]. On this basis superconducting quantum interference devices (SQUIDs) have been realized which exhibit excellent low noise behavior and high performance, making them suitable for the measurement of biomagnetic signals [22,23]. A systematic investigation of the microstructure of YBa2CuaO7 films deposited across steep steps in (001) LaAIOs substrates was carried out by high-resolution transmission electron microscopy (HREM) by Jia et al [20].…”

Section: Introductionmentioning

confidence: 99%

Structure of grain boundaries in YBa2Cu3O7 thin-film step-edge junctions

Jia

Urban

1994

Interface Sci

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The atomic structure of 90 ~ [100] (or [010]) tilt grain boundaries in YBa2Cu307 thin-film step-edge junctions and, for comparison, in the interface between a-axis and c-axis oriented YBa2Cu307 grains is investigated by means of high-resolution transmission electron microscopy. For (100)(001)-type boundaries two different structures are found. In the first a (001) CuO2 plane of one grain faces a (100) Y-Ba-O plane of the other grain, in the second a (001) BaO plane faces a (100) Cu-O plane. In the former structure an incomplete unit ceil of YBa2Cu307 terminates at the boundary and a smaller strain in the adjacent CuO2 planes is detected in comparison with the latter. It is found that a combination of a partial dislocation with a "124" stacking fault is a way to accommodate the lattice mismatch between c and 3a of YBa2Cu307 in the boundary. For a symmetric (103)(103)-type boundary a displacement of the Cu-atoms of the CuO2 planes is found near the boundary plane. From this a redistribution of the oxygen atoms around the Y-atoms located right in the boundary plane is inferred. The possible effect of the boundary structure on the superconducting properties of YBa2Cu307 films is discussed.

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Magnetoencephalography using high temperature rf SQUIDs

Cited by 34 publications

References 6 publications

High-transition-temperature superconducting quantum interference devices

High-transition-temperature superconducting quantum interference devices

Similarities and differences between on-scalp and conventional in-helmet magnetoencephalography recordings

Structure of grain boundaries in YBa2Cu3O7 thin-film step-edge junctions

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