Bright light was an effective aversive stimulus for Wistar rats in punishment, escape, and avoidance paradigms. Contingent punishment of lever-pressing maintained by concurrent schedules of food delivery shifted presses to an alternate lever, and depressed overall response rates. Periodic non-contingent presentation of the light prompted escape responding (head entry into a hole). Unsignaled avoidance contingencies were not effective, but pre-pulse signaling of light supported avoidance behavior. These results demonstrate a possible alternative to foot-shock, one with greater ecological validity, and one that might avoid some of the physiological effects that accompany electric shock.
KeywordsAvoidance; Escape; Punishment; Burrow; Light Aversion; Rat Electric footshock has served as the prototypical aversive stimulus in experimental preparations using rats [34,30]. Footshock is popular for its reliability, utility at a wide range of current, and the feasibility of titrating shock levels for individual subjects. But electric shock has its downsides: It often induces secondary effects such as long term sleep disruption [41], altered social behavior [27], reduction in locomotion, rearing, and grooming behaviors, as well as an increase in immobility and defecation [45]. Footshock has also received criticism when used to model conditions such as depression or anxiety disorder that are produced by stressors that lack a comparable component of pain [28]. Finally, the nature