Figure 2. Greater Translocator Protein (TSPO) Distribution Volume (VT) in Orbitofrontal Cortex Is Correlated With Distress Associated With Preventing Compulsive Behaviors.
Greater TSPO VT was significantly correlated with greater distress associated with preventing compulsive behaviors as reported on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). The single-nucleotide polymorphism rs6971 of the TSPO gene influences binding of second-generation TSPO positron emission tomography radioligands, including fluorine F 18–labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide. For the purposes of the display, corrected TSPO VT values for genotype are shown. For this, a linear model of TSPO VT = b0+b1*genotype was applied and b1 = 4.158 in the obsessive-compulsive disorder data set. Because the effect of genotype corresponded to a b1 value of 4.158, mixed-affinity binding (MAB) TSPO VT values were raised by 4.158 to visually correct them to high-affinity binding (HAB) TSPO VT values. Note, for this data set, this approach provided visually similar TSPO VT value corrections as are found with the other approach of multiplying TSPO VT from MAB cases by 1.4. For this polymorphism, high-affinity homozygotes are denoted as HAB and heterozygotes are denoted as MAB.