neutral masking face of the same poser for 170 milliseconds. Trials were separated by a 1 second interstimulus interval. Blocks 1, 3 and 5 consisted of neutral targets and neutral masks while blocks 2 and 4 were comprised of emotional targets and neutral masks. No commingling of emotional stimuli type occurred within a scanning epoch- only one emotional target type per scan was presented. Stimuli were presented this way to facilitate contrast analyses between the emotional masked stimuli and the neutral condition of neutral targets followed by neutral masks. The paradigms were presented using Psyscope 1.2.5 software generated from a Macintosh G5 computer and were rear projected onto a screen placed behind the top of the bore, visible through the mirror on the head coil. Immediately upon completion of the functional scan, subjects were presented with a post-test that included all facial expression stimuli and were asked to indicate for each expression whether it had been seen during the study. Subjects were also asked to describe what they had seen of the presented faces, and all reported the faces seen as having neutral expressions.
