Skip to main content
. 2019 Oct 25;10:768. doi: 10.3389/fpsyt.2019.00768

Figure 4.

Figure 4

Mixed-cue fear-conditioning test. (A) Overview of the test procedure. On the first day (fear conditioning), animals received three sessions of 30 s of an auditory cue, of which the last 2 s was paired with 0.7 mA foot shock. On day 2, the extinction learning, the auditory cue was presented during 15 trials of 30 s without the shock. Animals were injected with either MPH or vehicle 20 min before this task. On the third day, the extinction test, the auditory cue was presented during 15 trials of 30 s each. (B) The time spent freezing on the extinction learning day decreased with the methylphenidate (MPH) dose. (C) The number of beam breaks is presented during the habituation phases (CS−) of the fear conditioning (FC) and extinction learning (EL) and during the presentation of the auditory cue (CS+) during EL. (D) The number of beam breaks of the habituation phases is compared between all three testing days. (E) The graph represents the cumulative number of beam breaks on the extinction learning day and (F) extinction test day. Abbreviations: FC, fear conditioning; EL, extinction learning, i.p., intraperitoneal; CS−, conditioned stimulus absent; CS+, conditioned stimulus present; VEH, vehicle; MPH3, 3 mg/kg i.p. MPH; MPH10, 10 mg/kg i.p. MPH. N = 12 per group, #p < 0.010; *p < 0.05; **p < 0.01; ***p < 0.001.