Table 2.

Overview of study characteristics and outcome data that were extracted

Study categories	Extracted study characteristics
Animal characteristics and housing conditions	Species, strain, sex, body weight, age, group- or single-housing, time of testing relative to dark–light cycle
Experimental conditions
General	Brand of test chambers, calibration of the test box, background noise intensity, acclimation procedure
Acquisition training	Foot shock intensity, shock duration, cue-light duration, the timing of the shock relative to cue presentation, number of cue-shock pairings, mean interval between pairings, number of conditioning sessions per day
Test session	The time between training and test, characteristics of context, acclimatization, and habituation, number of cued and non-cued trials per session, trial order, startling noise intensity, startling noise duration, the interval between stimuli, cue-light duration, the timing of startling noise relative to cue light presentation, duration of data sampling, number of tests per week
Pharmacological intervention	Drug name, mode of action, dose (mg/kg), route of administration, injection-test interval
Outcome measures	Group mean and disperion for baseline startle (i.e., startle responses to non-cued trials), fear-potentiated startle (i.e., startle responses to cued trials), percent fear potentiation, absolute difference between the startle responses to cued and non-cued trials (i.e., difference score). Number of animals in the intervention and control groups, and study design (within or between-subjects design)
Reporting of key study quality indicators	Reporting of randomization at any level (yes/no), reporting of allocation based on baseline characteristics (yes/no), reporting of blinding at any level (yes/no), and reporting of a sample size calculation (yes/no)