Sensory responsiveness and avoidance learning in rats.

Analysis of sensory responsiveness and avoidance learning was carried out in three experiments using five rat strains. There were significant differences among the strains in response to electric footshock. Also the strain-specific shock intensity as unconditioned stimulus (US) elicited significantly higher rates of avoidance learning as compared with the rates of avoidance learning under an equal but average level of shock intensity as US. In general, discrete auditory and visual sensory modes as conditioned stimuli (CS) produced almost the same rate of avoidance learning. The proportion of variation in avoidance learning attributable to strains was significant under all six experimental conditions except no-discrete CS and strain-specific US condition.