RT Journal Article
SR Electronic
T1 Generators and connectivity of the early auditory evoked gamma band response
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 014514
DO 10.1101/014514
A1 Nenad Polomac
A1 Gregor Leicht
A1 Guido Nolte
A1 Christina Andreou
A1 Till R. Schneider
A1 Saskia Steinmann
A1 Andreas K. Engel
A1 Christoph Mulert
YR 2015
UL http://biorxiv.org/content/early/2015/01/28/014514.abstract
AB Background: High frequency oscillations in the gamma range are known to be involved in early stages of auditory information processing in terms of synchronization of brain regions, e.g., in cognitive functions. It has been shown using EEG source localisation, as well as simultaneously recorded EEG-fMRI, that the auditory evoked gamma-band response (aeGBR) is modulated by attention. In addition to auditory cortex activity a dorsal anterior cingulate cortex (dACC) generator could be involved. In the present study we investigated aeGBR magnetic fields using magnetoencephalography (MEG). We aimed to localize the aeGBR sources and its connectivity features in relation to mental effort.Methods: We investigated the aeGBR magnetic fields in 13 healthy participants using a 275-channel CTF-MEG system. The experimental paradigms were two auditory choice reaction tasks with different difficulties and demands for mental effort. We performed source localization with eLORETA and calculated the aeGBR lagged phase synchronization between bilateral auditory cortices and frontal midline structures.Results: The eLORETA analysis revealed sources of the aeGBR within bilateral auditory cortices and in frontal midline structures of the brain including the dACC. Compared to the control condition the dACC source activity was found to be significantly stronger during the performance of the cognitively demanding task. Moreover, this task involved a significantly stronger functional connectivity between auditory cortices and dACC.Conclusion: In accordance with previous EEG and EEG-fMRI investigations, our study confirms an aeGBR generator in the dACC by means of MEG and suggests its involvement in the effortful processing of auditory stimuli.