Imaging Protocols
During the behavioral paradigm, 64 T2-weighted images depicting
contrasts in blood-oxygen-level-dependent (BOLD) responses
were acquired by using a Siemens 1.5-T VISION Plus
system at 18 axial 6-mm slices (gap=0.6 mm) parallel to the intercommissural
line (TE=40 msec, TR=3 seconds, matrix=128×128).
Data for skin conductance arousal responses were acquired simultaneously
by using a customized electrodermal skin conductance
system (14), which did not require postacquisition data filtering.
Silver-silver chloride electrodes with 0.05 M sodium
chloride gel were placed on the distal phalanges of digits II and III