Abstract:

Music perception and cognition involves multi-modal processing within a wide range of neural networks working in concert. Rhythmic brain activities, or neural oscillations, are thought to play an important role in such long-range communication. How a re related networks established and dynamically reconfigured in order to adapt to the ever changing auditory environment? Oscillations in the 40-Hz range (gamma band) in thalamocortical connections are proposed as a key mechanism. A common problem to delineate the behavior of 40-Hz oscillatory activity, however, is the small effect size and unknown time, courses when using noninvasive megnetoencephalography (MEG) recording. To overcome this problem, auditory stimulation with sounds containing a strong 40-Hz rhythm can be used to drive neural networks into a state of high synchrony. These areas are successfully identified by beamforming techniques, which transform MEG signals to voxel-based source images. Phase lags between primary auditory cortices and thalamus and auditory association areas suggest the information flow across the regions. Moreover, changes in the sound stimulus were observed as temporal changes of synchrony reflecting dynamic reconfiguration of neural networks. The relevance of these observations for detecting changes in sound localization will be demonstrated.