Submitted on October 19, 2007
Accepted on July 31, 2008
Frequency-specific coupling in the cortico-cerebellar auditory system
Maria A. Pastor1*, Carmen Vidaurre1, Maria A. Fernandez Seara1, Arantxa Villanueva1, and Karl J Friston2
1 Department of Neuroscience, University of Navarra, Center for applied Medical Research, Pamplona, Navarra, Spain
2 Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College of London, London, London, United Kingdom
* To whom correspondence should be addressed. E-mail: mapastor{at}unav.es.
Induced oscillatory activity in the auditory cortex peaks at around 40Hz in humans. Using regional cerebral blood flow (rCBF) and positron emission tomography (PET) we previously confirmed frequency-selective cortical responses to 40Hz tones in auditory primary cortices and concomitant bilateral activation of the cerebellar hemispheres. In this study, using functional magnetic resonance imaging (fMRI) we estimated the influence of 40Hz auditory stimulation on the coupling between auditory cortex and Superior Temporal Sulcus (STS) and Crus II, using a dynamic causal model (DCM) of the interactions between medial geniculate nuclei, auditory STG/STS and the cerebellar Crus II auditory region. Specifically, we tested the hypothesis that 40Hz-selective responses in the cerebellar Crus II auditory region could be explained by frequency-specific enabling of interactions in the auditory cortico-cerebellar-thalamic loop. Our model comparison results suggest that input from auditory STG/STS to cerebellum is enhanced selectively at gamma band frequencies around 40 Hz.
