Abstract
This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects.
Original language | English (US) |
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Pages (from-to) | 11037-11041 |
Number of pages | 5 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 88 |
Issue number | 24 |
DOIs | |
State | Published - 1991 |
Externally published | Yes |
Keywords
- Alzheimer disease
- Auditory activity
- Cognition
- Magnetic resonance imaging
ASJC Scopus subject areas
- General