Fig. 1.

Experimental timeline. Mice were assessed on the behavior pattern monitor (BPM) prior to any exposure to either methamphetamine (METH) or doxycycline (DOX)-induced Tat expression to establish a behavioral baseline. When the METH exposure regimen began, mice were treated with a low dose (1 mg/ml) and slowly increased to a higher dose (6 mg/ml). After the first four-day block of injections, injections began with a mid-range dose (3 mg/mL) and ended with the highest dose (6 mg/ml). Mice were treated four days in a row at four different time points (1000, 1200, 1400, 1600 h) separated by a three-day period without injections. The four-day block of injection occurred four separate times and the entire regimen lasted 25 days. Mice were further assessed on the BPM near the end of the METH regimen (day 23) and on Day 32 (2 days after the end of DOX injections and 7 days following METH exposure).