Plots of the normalized mean BOLD signal for each subject in the disgust > neutral contrast against CAG repeat length repeat length (left) and probability of disease onset in 5 years (right). Black circles represent subjects with pre-manifest Huntington's disease and white diamonds represent controls. Controls are plotted against a CAG repeat length repeat length of 18 based on a previous study showing a mean CAG repeat length repeat length of 18 in 360 controls (Snell et al., 1993), and a probability of manifest disease onset within 5 years of 0. PDO = probability of disease onset within 5 years.