The electrical activity of brain, heart and skeletal muscles generates magnetic fields but these are recordable only macroscopically, such as in magnetoencephalography, which is used to map neuronal activity at the brain scale. At the local scale, magnetic fields recordings are still pending because of the lack of tools that can come in contact with living tissues. Here we present bio-compatible sensors based on Giant Magneto-Resistance (GMR) spin electronics. We show on a mouse muscle in vitro, using electrophysiology and computational modeling, that this technology permits simultaneous local recordings of the magnetic fields from action potentials. The sensitivity of this type of sensor is almost size independent, allowing the miniaturization and shaping required for in vivo/vitro magnetophysiology. GMR-based technology can constitute the magnetic counterpart of microelectrodes in electrophysiology, and might represent a new fundamental tool to investigate the local sources of neuronal magnetic activity.
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http://dx.doi.org/10.1038/srep39330 | DOI Listing |
Phys Rev Lett
December 2024
Laboratoire De Physique de l'École Normale Supérieure, ENS, PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75005 Paris, France.
Electric quadrupole traps are a leading technology for suspending charged objects ranging in size from single protons to atomic and molecular ions, and even to nano- and micron-sized bodies. If the levitated objects' charge distribution contains multipoles, the time-dependent trapping fields can significantly impact its rotational motion. Here, we experimentally observe the transition from librational motion to a regime where a microparticle rotates in sync with the trap drive.
View Article and Find Full Text PDFSci Adv
January 2025
Institute of Molecular Physical Science, ETH Zurich, 8093 Zurich, Switzerland.
Dynamic nuclear polarization (DNP) and emerging quantum technologies rely on the spin transfer in electron-nuclear hybrid quantum systems. Spin transfers might be suppressed by larger couplings, e.g.
View Article and Find Full Text PDFJ Vis
January 2025
Department of Psychology, University of Washington, Seattle, WA, USA.
The population receptive field (pRF) method, which measures the region in visual space that elicits a blood-oxygen-level-dependent (BOLD) signal in a voxel in retinotopic cortex, is a powerful tool for investigating the functional organization of human visual cortex with fMRI (Dumoulin & Wandell, 2008). However, recent work has shown that pRF estimates for early retinotopic visual areas can be biased and unreliable, especially for voxels representing the fovea. Here, we show that a log-bar stimulus that is logarithmically warped along the eccentricity dimension produces more reliable estimates of pRF size and location than the traditional moving bar stimulus.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Illinois Institute of Technology, Chicago, IL, USA.
Background: Intracranial atherosclerosis is a common age-related neuropathology that has been linked to cognitive decline and dementia and often mixed with Alzheimer's and other neuropathologies. But the association of atherosclerosis with brain morphometric abnormalities has not been explored. This work combined Deformation-based morphometry on ex-vivo MRI with detailed neuropathological examination in a large number of community-based older adults to investigate the association.
View Article and Find Full Text PDFNanoscale
January 2025
Wenzhou Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China.
As advanced materials, chiral nanomaterials have recently gained vast attention due to their special geometry-based physical and chemical properties. The fast development of the related science and technology means that various devices involving polarization-based information encryption, photoelectronic and spintronic devices, 3D displays, biomedical sensors and measurement, photonic engineering, electronic engineering, solar devices, , been explored extensively. These fields are at their beginning, and much effort needs to be made, including improving the optical, electronic, and magnetic properties of advanced chiral nanomaterials, precisely designing materials, and developing more efficient construction methods.
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