Interaction of age and shock intensity on acquisition of a discriminated conditioned emotional response.

Abstract

Rats 40, 90, and 354 days old were trained to learn a discriminative CER using US shock of .5 and 1.0 ma. In the second study the difficulty of the discrimination was reduced by changing the characteristics of the CS+ and OS-and setting US shock at .6 ma. Deprivation schedules were adjusted daily to the animals' growth rates. Rate of acquisition was a function of shock intensity and inversely related to problem difficulty and age. Differences between this study and other studies are attributed partly to the procedure of age-corrected body weight used in this study.

Retroactive stimulus interference with conditioned emotional response retention in infant and adult rats: Implications for infantile amnesia.

“…However, the CER acquisition data presented in Experiment 1 speak against this, as do the vast majority of experimental reports from the animal literature. Of 26 reports examined in conjunction with the present work, only 3 (McGaughey & Thompson, 1975;Nagy, Thaller, & Mazzaferri, 1977, Experiment 2;Pare, 1969) reported faster acquisition by younger animals in an aversive situation, and 1 of these (Pare, 1969) defined 40-day-old animals as "young." For appetitively motivated tasks, the imbalance is not quite so severe.…”

Sexual dimorphism in passive avoidance behavior of rats: Relation to body weight, age, shock intensity and retention interval

“…This sexual dimorphism is independent of factors such as body weight, age (at least within the limit of this study) and the intensity of foot shock which was used as aversive stimulus during the single learning trial. Accordingly, weight-and age-dependent differences in reactivity to foot shock [ 16] cannot explain the sexual dimorphism in passive avoidance behavior. Our observations however pointed to the importance of the learningretention test interval.…”

“…Passive avoidance retention of male rats is a function of shock intensity, shock duration and the learning-retention interval [1]. Reactivity to electric foot shock also is related to the sex [3, 8,12,15], body weight and age [16]. Since differences in reactivity to foot shock, which is used as aversive stimulus at the learning, may influence later retention of a passive avoidance response, the present experiments were designed to investigate sexual dimorphism in the retention of a passive avoidance response in relation to body weight, age, shock intensity and learning-retention interval.…”

Classically conditioned cardiac responses in "old" and "young" Fischer 344 rats.

“…Simple eyelid conditioning was also reported to be impaired in humans (Braun & Geiselhart, 1959;Kimble & Pennypacker, 1963), rabbits (Graves & Solomon, 1985;Powell et al, 1981Powell et al, , 1984, and cats (Harrison & Buchwald, 1983). Old rats were also reported to show deficits in a conditioned suppression paradigm, which, of course, also involves a Pavlovian conditioning contingency (Pare, 1969;Solyom & Miller, 1965). However, other experiments suggested that these results may have been due to a decreased sensitivity to the shock UCS in these animals (Pare, 1969).…”