Subjects choose between a stimuli-pair at the first stage which leads with fixed probability ( = 0.70) to one of two states at the second stage. Subjects then choose between one of two stimuli-pairs at the second stage which are associated with a shifting probability of reward based on a random Gaussian walk. The reward outcome is shown. Region of interests Top: freesurfer parcellation. Middle and bottom: Regions of interest. The caudate is shown in blue; the putamen is shown in green; the nucleus accumbens (ventral striatum) is shown in yellow. The medial orbitofrontal cortex parcellation shown in the Free Surfer parcellation (top) consisted of both the ventromedial prefrontal cortex and medial orbitofrontal cortex (shown in red at the bottom). For illustration purposes, the Free Surfer reconstruction is shown overlaid on the MNI152 brain (middle and bottom).
展开▼
