Effective connectivity of human lateral occipital complex (LOC) during visuo-haptic object perception

van den Bosch, J. F., Yalachkov, Y., Doehrmann, O., Kaiser, J., and Naumer, M. J.
Institut für Medizinische Psychologie, Goethe Universität Frankfurt

In the human brain, visuo-haptic (VH) object perception involves a distributed network of functionally connected cortical as well as subcortical regions. In order to investigate directed influences between these regions we applied Granger causality mapping (GCM) to an fMRI data set acquired during visual, haptic, and visuo-haptic object perception. Wooden 3D objects were presented either unimodally (V; H) or bimodally (VH). Effects of VH integration (M<V<VH>H>M) were found in a network of brain regions including left LOC, bilateral IPS, and the lateral cerebellum, bilaterally. These regions were used as so-called seed regions for subsequent GCM. Preliminary results showed that LOC activation is predicted more reliably during unimodal haptic as compared to unimodal visual stimulation. During bimodal VH stimulation, however, LOC activation is predicted best by several cortical as well as subcortical regions. Based on additional analyses we will report comprehensive results for all seed regions used.