Area PFcm is comparable by its location and extent to area Spt, which supports auditory-motor integration for speech (Hickok et al., 2003). Although areas PFcm and pSTG/STS are assigned to different branches in the cluster tree (Fig. 4A), the multidimensional scaling analysis reveals that, out of the inferior parietal areas, the fingerprint of PFcm is the nearest neighbor of the pSTG/STS (Fig. 4B). This relationship could be caused by the fact that area Spt is known to be connected with the language area pSTG (Hickok and Poeppel 2007). The difference between the results of the hierarchical cluster tree and the multidimensional scaling analyses reflects different
perspectives on the similarity criteria used for the analyses of multireceptor fingerprints. Cell Cycle inhibitor Whereas the hierarchical cluster analysis is based on a recursive algorithm which minimizes the total within cluster variance, the multidimensional scaling presents the best 2-dimensional representation of the distances between the fingerprints of the examined areas in a 15-dimensional (15 different receptors representing a fingerprint) space without applying any linkage between areas during the calculation process. Concluding, the tight clustering of the receptor fingerprints of all language-related selleck areas in the left hemisphere is impressive despite their cytoarchitectonical diversity and the fact that
they are topographically widely distributed C1GALT1 throughout the brain from the IFG to the posterior part of the superior temporal gyrus. The multireceptor fingerprint analysis provides the first evidence for a common molecular basis of interaction in the functionally defined sentence comprehension network. Cortical areas distinct by their multireceptor expression and defined by their function in encoding and decoding of words, and syntactically complex, verbal working memory demanding sentences interact in this network. Note, that on the basis of these data we are not claiming any language specificity of molecular fingerprints. We
rather suggest that brain regions which work together in a functional network are characterized by a similarity in their fingerprints, which differ from those of other networks. Interestingly, we found a higher similarity of the receptor fingerprints in the frontal and temporal language regions extracted from the left, language dominant hemisphere, as compared to the right hemisphere. This work was supported by grants of the European FET flagship project “Human Brain Project” (Subproject 2, Strategic Human Brain Data, WP2.1: Multi-level organisation of the human brain, T2.1.1: Distribution of receptors in the human cerebral cortex to K.Z. and K.A.), the Portfolio Theme “Supercomputing and Modeling for the Human Brain” of the Helmholtz Association, Germany (to K.A. and K.Z.), and the Doctoral Program of the Max Planck Institute for Human Cognitive and Brain Sciences (to M.B.-T.).