Four experiments manipulated the context in which taste-aversion conditioning occurred when the reinforcer was devalued after instrumental learning. In all experiments, rats learned to lever press in an operant conditioning chamber and then had an aversion to the food-pellet reinforcer conditioned by pairing it with lithium chloride (LiCl) in either that context or a different context. Lever pressing was then tested in extinction to assess its status as a goal-directed action. In Experiment 1, aversion conditioning in the operant conditioning chamber suppressed lever-pressing during the test, but aversion conditioning in the home cage did not. Exposure to the averted pellet in the operant conditioning chamber after conditioning in the home cage did not change this effect (Experiment 2). The same pattern was observed when the different context was a second operant-style chamber (counterbalanced), exposure to the contexts was controlled, and pellets were presented in them in the same manner (Experiment 3). The greater effect of aversion conditioning in the instrumental context was not merely due to potentiated contextual conditioning (Experiment 4). Importantly, consumption tests revealed that the aversion conditioned in the different context had transferred to the test context. Thus, when reinforcer devaluation occurred in a different context, the rats lever pressed in extinction for a reinforcer they would otherwise reject. The results suggest that animals encode contextual information about the reinforcer during instrumental learning and suggest caution in making inferences about action versus habit learning when the reinforcer is devalued in a different context.

Extinguished responding will renew when the conditioned stimulus occurs outside the extinction context. Although studies of conditioned freezing have consistently demonstrated a role for the hippocampus in renewal, several studies have demonstrated intact renewal of conditioned suppression despite damage to the hippocampus (Frohardt, Guarraci, & Bouton, 2000; Todd, Jiang, DeAngeli, & Bucci, 2017; Wilson, Brooks, & Bouton, 1995). Because these prior studies have examined renewal when testing occurred in the original conditioning context (“Context A”), the present conditioned suppression experiments examined the role of the hippocampus when testing occurred in a context not associated with prior conditioning (“Context C”). In Experiments 1 and 2, conditioning occurred in Context A, and extinction in Context B. Renewal of conditioned suppression was observed when the extinguished conditioned stimulus (CS) was tested in Context C. However, renewal was attenuated in rats with lesions of the dorsal hippocampus (DH). Summation testing failed to detect conditioned inhibition in the extinction context, suggesting instead that the context acquired negative occasion-setting properties. Attenuated renewal was not due to an inability of DH lesioned rats to discriminate contexts (Experiment 3). These experiments thus demonstrate a role for the DH in renewal of conditioned suppression when testing occurs in a neutral context.

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There are numerous reports regarding the antimicrobial effects of herbal extracts on bacteria and fungi. We have prepared water extracts of Wild Leek (A. ampeloprasum var. porrum), Kurrat (A. ampeloprasum var. kurrat) and Elephant Garlic (A. ampeloprasum var. ampeloprasum) by rotary vacuum distillation. As a result, the extraction was carried out in 40 ℃ thus omitting any risk of loss of anti-bacterial activity due to high temperatures reported in prior similar studies [1]. The five bacteria Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus were tested against the extracts. While some extent of inhibition was observed when the bacteria were cultured in presence of the leek and kurrat extracts, elephant garlic was determined to possess an extreme inhibitory quality against all the aforementioned bacteria, completely inhibiting the growth of the bacteria after 24 hrs of culture in exposure to the extract. We propose that elephant garlic extract could be an effective alternative to chemical antibiotic treatments and disinfectants in hospital and other settings in which infections are common.

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