[Paleopsych] Oscillatory activity in the magnetoencephalogram during auditory processing and action preparation

[Steve Hovland]

http://www.mp.uni-tuebingen.de/mp/index.php?id=131
Prof. Dr. Jochen Kaiser  <mailto:j.kaiser at med.uni-frankfurt.de>1 Prof. Dr. 
Werner Lutzenberger  <mailto:werner.lutzenberger at med.uni-tuebingen.de>2 
Dipl.-Psych. Susanne Leiberg 
 <mailto:susanne.leiberg at med.uni-tuebingen.de>2, 3
1 Institute of Medical Psychology, University of Frankfurt
2 Institute of Medical Psychology and Behavioral Neurobiology, University 
of Tubingen
3 Graduate School of Neural and Behavioral Sciences, University of Tubingen 
The topography and time course of high frequency oscillatory activity in 
the magnetoencephalogram (MEG) is studied by means of a statistical 
probability mapping (for details see Lutzenberger et al., 2002). Our 
research has two main foci:
Gamma band activity (GBA) during auditory processing
We investigate the role of GBA in bottom-up and top-down driven processing 
of auditory information. Studying working memory for spectral and spatial 
features of auditory stimuli we have found gamma band activity over the 
putative auditory ventral and dorsal processing streams and over prefrontal 
areas. These results suggest that the maintenance of auditory information 
in working memory relies on the synchronisation of the firing activity in 
neural networks belonging to the putative auditory processing streams and 
prefrontal, supposedly executive regions. In upcoming studies we want to 
gain further information about the role of GBA in top-down processes like 
working memory and selective attention. We also want to study the alleged 
relationship between the BOLD signal in fMRI and GBA in MEG using the same 
experiments and the same subjects. The topographical convergence between 
our GBA findings in auditory working memory studies and the BOLD findings 
in fMRI studies using similar paradigms supports the results of recent 
studies which point to an existing relationship between gamma oscillations 
and changes in blood oxygen level as measured with fMRI.