Abstract
The recent technological developments in PET, SPECT and NMR allow for detailed images of the anatomical structures or metabolical activity of the human brain. Given these non-invasive imaging facilities, one may wonder whether there remains a future for mapping the electromagnetic fields produced by the brain. Their spatial (3-D) resolution for localizing activity is comparable to e.g. NMR; in temporal resolution they will, however, remain superior to the above mentioned imaging techniques. Only recording of the electromagnetic fields enables to study the function of the brain with a time resolution comparable to the processing speed of the brain, i.e. of the order of 10 to 100 ms. I will illustrate in this review by means of the visual pattern onset response that such a time resolution is needed to discriminate between the various sources of activity within the human brain. In man these fields can be recorded by either measuring the gradient of the magnetic flux near the scalp surface or by metal macro-electrodes attached to the scalp. Examples of such recordings to left half field checkerboard onset stimulation are given in Fig. 1, which is taken from the Ph.D.-study of Stok (1986). The visual evoked potentials (VEPs) and the magnetic fields (MEFs) were recorded from the same subject to answer the question whether MEFs can be used to validate or extend results based on VEPs.
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Spekreijse, H. (1991). Localization of the Electromagnetic Sources of the Pattern Onset Response in Man. In: Valberg, A., Lee, B.B. (eds) From Pigments to Perception. NATO ASI Series, vol 203. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-3718-2_26
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DOI: https://doi.org/10.1007/978-1-4615-3718-2_26
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