Multiparametrische Analyse der Korrelation perzeptiver und kognitiver neuronaler Signale durch Integration von Magnetoenzephalographie und 3T-funktioneller Kernspintomographie
Final Report Abstract
The relationship between the BOLD-signal as recorded by fMRI to the cortical sourcestrength of oscillatory steady-state activity from human auditory cortex as assessed by MEG was established by recording evoked brain responses to amplitude-modulated tones with modulation frequencies between 10 and 60 Hz, separately in MEG and fMRI. The experimental design in both modalities, MEG and fMRI, was exactly the same. The comparability was controlled in great detail, e.g. the masking influence ofthe scanner noise onto the cortical signal strength was also included into the MEG evaluation. The most valuable and important scientific result was that the source strength determined by MEG positively correlated with the BOLD signal amplitude. With respect to the localization of cortical sources, the fMRI localized the auditory steady-state response at the primary auditory cortex, superior temporal cortex and middle temporal cortex. Additionally, we were able to successfully separate the transient, tone-onset related response, which is overlaid on the continuous periodic ASSR. Thus, fMRI-data revealed that the "sustained field response" was located to the superior temporal cortex.
