Efficient neuromagnetic determination of landmarks in the somatosensory cortex.
OBJECTIVE
An efficient procedure for the magnetoencephalographic determination of functional landmarks in the somatosensory cortex has been developed.


METHODS
Digits 2-5 are stimulated in randomized order using balloon diaphragms. The interval between two stimuli is 500 ms. Source locations in area 3b are derived by interpreting the field component with a mean latency of 48 ms in terms of an equivalent current dipole.


RESULTS
The signal-to-noise ratio achieved in a given time for each of the 4 stimulation sites turned out to be only slightly smaller than the one obtained by stimulating a single site with an optimal interstimulus interval (about 1 s).


CONCLUSIONS
Compared to a sequential investigation of the different sites, the proposed procedure allows the reduction of the overall measurement time by a factor of about 2.7.
Mertens
M
M
Institute of Experimental Audiology, University of Münster, Kardinal-von-Galen-Ring 10, D-48129 Münster, Germany.
Lütkenhöner
B
B
D000328:Adult; D001931:Brain Mapping; D004558:Electric Stimulation; D006801:Humans; D008280:Magnetics; D010812:Physical Stimulation; D013003:Somatosensory Cortex / Q000502:physiology*; D013997:Time Factors