, 2013a, Eickhoff et al., 2008, Palomero-Gallagher BMS-354825 ic50 et al., 2009, Zilles et al., 2002a and Zilles et al., 2004). Autoradiographic labeling of the sections with tritium [3H]-labeled ligands was performed according to standardized protocols (Zilles, Schleicher, et al., 2002; Supplementary Table 1). The experimental procedure included three successional steps:

1) Pre-incubation to rehydrate the tissue and remove endogenous ligands and other substances which potentially bind to the receptors. 2) Main incubation to label the receptors with only the respective tritiated ligands in nM, or with the tritiated ligands in presence of the respective non-labeled competitors in μM. By comparing these two experimental conditions, the specific binding could be calculated: The incubation with only the tritiated ligand denoted the total binding, whereas the incubation with the additional non-labeled competitor showed the non-specific binding. The specific binding was calculated as the difference between total binding and non-specific binding. It was less than 5% in all cases. MLN0128 supplier 3) Final rinsing to stop binding and remove superfluous radioactive ligands. Radioactively labeled

sections were co-exposed with [3H]-plastic scales of known radioactivity against [3H]-sensitive films for 4–18 weeks. The developed films were digitized using a CCD-camera. Gray values of the digitized images were transformed into radioactivity concentrations by a non-linear transformation computed from the gray values of the co-exposed plastic standards of known radioactivity concentrations. These linearized autoradiographs 4��8C were contrast enhanced, and color coded in a spectral color sequence for a better visualization of regional differences. Regions of interest were selected and defined using cyto- and receptor architectonical as well as landmark-based identification as described in the literature (Amunts et al., 2010, Amunts et al., 1999, Brodmann, 1909, Caspers et al., 2013a, Caspers

et al., 2013c, Eickhoff et al., 2007, Friederici et al., 2009, Geyer et al., 1997, Makuuchi et al., 2009, Morosan et al., 2005, Palomero-Gallagher et al., 2009, Scheperjans et al., 2005 and Zilles and Amunts, 2010). Receptor densities were extracted from the regions of interest based on a previously described densitometric analysis (Zilles, Schleicher, et al., 2002). For each of the examined receptor types, profiles oriented vertically to the cortical surface and covering the full cortical width were extracted from the linearized autoradiographs (Zilles, Schleicher, et al., 2002). The area below the profile quantifies the mean areal density in fmol/mg protein. Densities were averaged over three sections and four hemispheres, and provided the mean value for each receptor in each area. These values were registered for each area separately in a polar plot.