6 (3.6) years old, 15.2 (4.8) cigarettes/day, and 4.2 (1.3) FTND score. For comparison, we also examined responding in those unable to http://www.selleckchem.com/products/lapatinib.html quit during the first day of both medication conditions (n = 5). Of those unable to quit (five women), three were Caucasian and two Blacks, and mean characteristics were 39.0 (5.6) years old, 14.8 (4.6) cigarettes/day, and 6.0 (1.6) FTND score. Reinforcement Task Reinforcement was determined by number of responses on a modified operant computer program called ��Applepicker�� (AP; Norman & Jongerius 1985), used in many prior studies (e.g. Epstein, Bulik, Perkins, Caggiula, & Rodefer, 1991; Perkins, Epstein, Grobe, & Fonte, 1994). The available reinforcer was 30 s of the participant��s preferred music, provided by the participant in an electronic format (e.g.
CD) during screening. The AP task required using arrows on a keypad to move a cursor around a ��field�� of ��trees�� on a monitor, looking for ��apples.�� Pressing a button on the keypad constituted a response, and finding an apple signaled that 30 s of music (i.e. one reinforcer) had been earned. The number of responses required to find an apple was on a progressive ratio (PR) schedule, incrementing by 50% (i.e. PR50%), starting with 10 responses for the first reinforcer. When a reinforcer was earned, an apple symbol briefly appeared as feedback, and the music played immediately for 30 s. Upon earning a reinforcer, subjects could continue responding on the AP task without interruption, to extend the time of music.
They were free to stop responding at any point and read available magazines while waiting for the end of the 15-min task period (see Perkins et al., 2009). Procedures Ability to abstain from smoking for 24hr, defined as 0 cigarettes and confirmed by CO < 5 ppm (Javors, Hatch, & Lamb, 2005), was a dependent measure in the primary study, which assessed days quit during week-long use of bupropion versus placebo, administered double-blind (see similar procedures in Perkins et al., 2010). Testing occurred on three occasions: after smoking ad libitum during the baseline week prior to receiving any medication, and on the first day of each of 2 week-long quit attempts on bupropion or on placebo, with the order of medication conditions counter-balanced. Each quit attempt was preceded by a week of dose run up.
Upon arrival to each session, participants provided expired-air CO and completed the Questionnaire on Smoking Urges-brief measure of craving (Cox, Tiffany, & Christen, 2001) and the Minnesota Nicotine Withdrawal Scale measure of withdrawal (Hughes & Hatsukami, 2007). They then engaged in the AP task for music reinforcement in a quiet room with no one else present. During the prequit baseline, all subjects ad lib smoked in the lab immediately prior to the AP task to equate time since last cigarette. These three AP task sessions were separated by at least 10 days, with all participants resuming Brefeldin_A smoking (if quit) after each medication condition.