Magnetoencephalographic Signals and Their Registration
High resolution magnetoencephalography can play an important role in the extension and the deepening of the electroencephalographic method if a sufficient suppression of outer perturbation signals, especially at low frequencies, can be realized during the investigations of slow activity changes of the brain.
As an alternative solution for the shielded chamber, a SQUID (superconducting quantum interference device) gradiometer is put forward. This device was developed for making accurate measurements in an unshielded “near-bed” environment. The excellent performance of a five-channel device equipped with a balanceable second-order gradiometer and high-sensitivity SQUIDs will be demonstrated on the basis of magnetocardiographic measurements and preliminary magnetoencephalographic results.
KeywordsAlpha Wave Squid System Slow Potential Change Awake Rabbit Ground Magnetic Field
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- Albrecht G, Burghoff M, Gießler F, Haberkorn W, Nowak H (1989): High resolution magnetocardiography, source localization and multichannel magnetography. In: Advances in Biomagnetism, Williamson SJ, Hoke M, Stroink G, Kotani M, eds. New York: PlenumGoogle Scholar
- Berthe! K-H, Albrecht G, Kirsch G, Nowak H, Vodel W, Zach H-G (1986): Application of dc-SQUIDs for biomagnetic measurement. In: Proceedings of Fourth Czechoslovak Symposium on Weak Superconductivity, Smolenice/CSFR (Slovak Academy of Sciences, ed.)Google Scholar
- Deecke L (1990): Slow activity changes of the brain during motor and cognitive tasks. (in press)Google Scholar
- Emmerich E, Kirsch G, Richter F (1991): Visual evoked signals of the awake rabbit. (in press)Google Scholar
- Hoffmann K-P, Both R, Jans M, Kirsch G, Mühlau G, Nowak H (1991): Magnetic field of cerebral cortex measurements in an unshielded environment. (in press)Google Scholar
- Kelhä V, Peltonen R, Rantala B (1979): Construction of a magnetically shielded room. Proc. Annual Conf. Finnish Phys. Soc., Jyvàskylà, Finland, February 2–3, 1979Google Scholar
- Nowak H, Albrecht G, Berthe! K-H (1988a): Anwendung supraleitender Sensoren für biomagnetische Messungen. (mst 31 ) 8: 351–355Google Scholar
- Nowak H, Albrecht G, Berthel K-H, Burghoff M, Haberkorn W, Zach H-G (1988b): Biomagnetic measurements in an unshielded environment. In: Advances in Biomedical Measurements, Carson ER, ed. New York: Plenum PressGoogle Scholar
- Vodel W, Mäkiniemi K (1992): An ultra low noise SQUID system for biomagnetic research. To be published in: J Physics E: Scientific Instruments Google Scholar