We used a drug-word (DW) paradigm that has been previously described [14]. Briefly, 40 drug words matched on length, frequency in the English language, and part of speech (noun, adjective, adverb, verb) with 40 household-related (neutral) items were used (Fig. 1); non-English words or slang words that may have not been recognized by the control subjects were not included. These two word types (“Drug” and “Neutral”) were presented via MRI-compatible goggles in a blocked and counterbalanced fashion across subjects. Each of the 2 DW sequences (“drug” or “neutral”) had two 70-seconds long task epochs that included 20 trials. Each trial comprised a 500 ms fixation cross, a 2000 ms word presentation window, a 500 ms response window, and a 500 ms feedback where “O” and “X” were displayed for correct and incorrect trials, respectively. The words were presented using one of four possible colors (yellow, blue, red, green) and the word color order was pseudo randomized. Subjects were instructed to press one of four buttons (yellow, blue, red, green) of the MRI-compatible Lumina LP-400 response pad (Cedrus Corp., San Pedro,
