Título: | Choice of Magnetometers and Gradiometers after Signal Space Separation |
Autores: | Garcés, Pilar ; López-Sanz, David ; Maestú Unturbe, Fernando ; Pereda, Ernesto |
Tipo de documento: | texto impreso |
Editorial: | MDPI, 2017 |
Dimensiones: | application/pdf |
Nota general: |
cc_by info:eu-repo/semantics/openAccess |
Idiomas: | |
Palabras clave: | Estado = Publicado , Materia = Ciencias Biomédicas: Psicología: Psicología experimental , Tipo = Artículo |
Resumen: |
Background: Modern Elekta Neuromag MEG devices include 102 sensor triplets containing one magnetometer and two planar gradiometers. The first processing step is often a signal space separation (SSS), which provides a powerful noise reduction. A question commonly raised by researchers and reviewers relates to which data should be employed in analyses: (1) magnetometers only, (2) gradiometers only, (3) magnetometers and gradiometers together. The MEG community is currently divided with regard to the proper answer. Methods: First, we provide theoretical evidence that both gradiometers and magnetometers result from the backprojection of the same SSS components. Then, we compare resting state and task-related sensor and source estimations from magnetometers and gradiometers in real MEG recordings before and after SSS. Results: SSS introduced a strong increase in the similarity between source time series derived from magnetometers and gradiometers (r2 = 0.3–0.8 before SSS and r2 > 0.80 after SSS). After SSS, resting state power spectrum and functional connectivity, as well as visual evoked responses, derived from both magnetometers and gradiometers were highly similar (Intraclass Correlation Coefficient > 0.8, r 2 > 0.8). Conclusions: After SSS, magnetometer and gradiometer data are estimated from a single set of SSS components (usually ? 80). Equivalent results can be obtained with both sensor types in typical MEG experiments. |
En línea: | https://eprints.ucm.es/id/eprint/62235/1/sensors-17-02926.pdf |
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