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Biomedical subjects

A Amsel

Publications and source records attributed to A Amsel.

At least 55 records · Page 3Linked to original sources
PubMed1980

Recall (versus recognition) of taste and immunization against aversive taste anticipations based on illness.

Two experiments show that, after taste-aversion conditioning, rats can use external retrieval cues to recall or anticipate the aversive taste solution and avoid its location without making contact with the flavor. They also show that the rat's avoidance of a conditioned aversive taste and its consumption of the aversive flavored solution can be attenuated by giving it prior runway training in which taste reward is given inconsistently on a partial reinforcement schedule.

Animals↗
PubMed1980

Retention under changed-reward conditions of persistence learned by infant rats.

Two experiments were performed to determine whether or not persistence acquired under reinforcement conditions of infancy can be retained and transferred to adult reinforcing conditions. In Experiment I 2 groups of rats 14-15 days of age were trained in a runway under a partial (PRF) or continuous (CRF) schedule of milk-suckling reinforcement. A 3rd group was trained under continuous nonreinforcement (NRF) conditions. The PRF and CRF groups acquired the approach response about equally, and the NRF showed a very small increase in speed. In immediate extinction, the PRF group was more resistant to extinction than its CRS counterpart. For the NRF group "extinction" produced a continuation of the low-level "acquisition" performance. Experiment II showed that persistence acquired at 14-15 days with milk-suckling reinforcement can be sustained through a 2-week retention period including a phase of CRF food-pellet reward.

Aging↗
PubMed1980

Learned persistence at 11-12 days but not at 10-11 days in infant rats.

In 2 experiments using milk-suckling from an anesthetized dam as the reinforcer, evidence is presented that the transitional age in rat pups for learning of persistence as a result of appetitive partial reinforcement is between 11 and 12 days of age. In Experiment I, pups 12-13 days of age showed the partial reinforcement extinction effect (PREE) whereas 10-11-day olds did not. In Experiment II, pups trained at 11-12 days and tested at Day 13 did show a PREE at Day 13 but those trained at 10-11 days did not.

Aging↗
PubMed1980

Aversion learning in 5-day-old rats: taste-toxicosis and texture-shock associations.

Five-day-old rats that received a single pairing of a novel saccharin flavor with lithium treatment learned to suppress ingestion of saccharin on subsequent occasions (Experiment 1). This flavor aversion learning was inversely related to the interval between the novel flavor experience and drug administraton, wit h significant aversions being learned with intervals of 0 and 30 min but not with intervals of 60 and 90 min (experiment 2). The conditioning was observed when hypertonic lithium served as the unconditioned stimulus but did not occur with isotonic lithium or hypertonic saline injections (Experiment 3). These results indicate that flavor aversion learning in infant rats is a result of the joint action of two factors--pure drug effects and the somatic pain and irritation produced by the tonicity of the injected agent. The taste aversion learning was specific to the drug-paired flavor, and evidence was presented suggesting that 5-day-old rats display a natural hesitancy to consume novel edibles (neophobia) (Experiment 4). Experiment 5 demonstrated that 5-day-old rats selectively associate tactile stimuli with shock but not with the gastrointestinal consequences of lithium. Implications of the mechanisms involved in flavor aversion learning in infant rats are discussed as they relate to adaptation and food selection in adult animals.

Animals↗
PubMed1978

Ingestional aversion learning in preweanling rats.

Ingestional aversions were conditioned in 12- and 15-day-old rats by infusing a .5% solution of saccharin into the oral cavity and following this oral infusion by the injection of lithium chloride. At both ages, subjects for which the saccharin exposure was followed by lithium injection within 2-3 min drank less when the saccharin solution was again presented by oral infusion 12 hr later; such suppressions of intake were not observed in subjects that previously received the saccharin and lithium in an unpaired fashion (Experiments 1 and 3). Ingestional aversions were also learned by 12-day-olds when a 30-min interval was introduced between saccharin exposure and lithium toxicosis but not when toxicosis was delayed by 120 min (Experiment 2). In contrast, 15-day-olds learned aversions with both the 30- and 120-min-delay intervals (Experiment 3). Despite the absence of long-delay learning in 12 day olds, ingestional aversions conditioned at 12 days of age were retained for 2 wk (Experiment 4). These results provide further evidence of the associative abilities of neonatal rats and illustrate a developmental aspect of long-delay learning.

Age Factors↗
PubMed1977

Ultrasound emission in infant rats as an indicant of arousal during appetitive learning and extinction.

Infant rats rewarded for crawling by being allowed to suckle on the dry nipple of an anesthetized dam showed a decreasing rate of ultrasound production during acquisition and an increasing rate during extinction. These results suggest that infant rats can be stressed and are aroused as a result of successive nonrewards just as adult rats are. In addition, these results do not support the hypothesis that infant rats lack inhibitory mechanisms related to poorly developed neural centers.

Animals↗
PubMed1976

Ontogeny of persistence: immediate and long-term persistence in rats varying in training age between 17 and 65 days.

In Experiment 1, six age groups of rats were trained to run an alley for either partial (PRF) or continuous reinforcement (CRF). Training was during a 2-day period starting at six different ages, and extinction was initiated about 12 hr later. There was a clear partial reinforcement extinction effect (PREE) at all ages and, particularly after PRF training, an inverse relationship between resistance to extinction and age. In Experiment 2, retention and durability of persistence as well as immediate persistence were tested following acquisition at three different ages. The immediate extinction tests confirmed the results of Experiment 1. In the delayed extinction tests, greater resistance to extinction following PRF than following CRF was found in all age groups after both the retention and durability manipulations. In neither test was there an effect of age in original acquisition on the magnitude of adult persistence. These experiments confirm earlier findings of remarkable persistence in rats trained and tested at weanling age, show that the persistence is even greater in pre-weanlings, and show that it is retained into young adulthood.

Age Factors↗