Journal Article

PreJuSER-10821

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png BA3b and BA1 activate in a serial fashion after median nerve stimulation: Direct evidence from combining source analysis of evoked fields and cytoarchitectonic probabilistic maps

Papadelis, C. ; Eickhoff, S. B.FZJ* ; Zilles, K.FZJ* ; Ioannides, A. A.

2011
Academic Press Orlando, Fla.

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Please use a persistent id in citations: doi:10.1016/j.neuroimgage.2010.07.054

Abstract: This study combines source analysis imaging data for early somatosensory processing and the probabilistic cytoarchitectonic maps (PCMs). Human somatosensory evoked fields (SEFs) were recorded by stimulating left and right median nerves. Filtering the recorded responses in different frequency ranges identified the most responsive frequency band. The short-latency averaged SEFs were analyzed using a single equivalent current dipole (ECD) model and magnetic field tomography (MET). The identified foci of activity were superimposed with PCMs. Two major components of opposite polarity were prominent around 21 and 31 ms. A weak component around 25 ms was also identified. For the most responsive frequency band (50-150 Hz) ECD and MFT revealed one focal source at the contralateral Brodmann area 3b (BA3b) at the peak of N20. The component similar to 25 ms was localised in Brodmann area 1 (BA1) in 50-150 Hz. By using ECD, focal generators around 28-30 ms located initially in BA3b and 2 ms later to BA1. MET also revealed two focal sources one in BA3b and one in BA1 for these latencies. Our results provide direct evidence that the earliest cortical response after median nerve stimulation is generated within the contralateral BA3b. BA1 activation few milliseconds later indicates a serial mode of somatosensory processing within cytoarchitectonic SI subdivisions. Analysis of non-invasive magnetoencephalography (MEG) data and the use of PCMs allow unambiguous and quantitative (probabilistic) interpretation of cytoarchitectonic identity of activated areas following median nerve stimulation, even with the simple ECD model, but only when the model fits the data extremely well. (C) 2010 Elsevier Inc. All rights reserved.

Keyword(s): J ; Somatosensory evoked fields (auto) ; Serial processing (auto) ; Median nerve (auto) ; Cytoarchitectonic probabilistic maps (auto)

Note: We thank all the staff of the Laboratory for Human Brain Dynamics (1999-2009) at the Brain Science Institute, RIKEN and especially Mr. Kenji Haruhana for the assistance with the experiment. The experiment and data analysis were performed at RIKEN and the work was continued by the authors at their new posts in Italy and Cyprus. Following the closing of the MEG laboratory at RIKEN in September 2009, the contribution from AAI was supported by Cyprus Research Promotion Foundation grants (upgrade/info/0308/02 and human/sociol/0308/BE). SBE was supported by the Human Brain Project (R01-MH074457-01A1), and SBE and KZ by the Helmholtz Initiative on Systems Biology "The Human Brain Model".

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Contributing Institute(s):

1. Molekulare Organisation des Gehirns (INM-2)

Research Program(s):

1. Funktion und Dysfunktion des Nervensystems (FUEK409) (FUEK409)
2. 89571 - Connectivity and Activity (POF2-89571) (POF2-89571)

Appears in the scientific report 2011

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