| Abstract No.: | C-G3197 |
| Country: | Canada |
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| Title: | EFFECT OF BASOLATERAL AMYGDALA LESIONS ON LEARNING CONDITIONED TASTE AVOIDANCE |
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| Authors/Affiliations: | 1 Selma Hamdani*; 1 Norman M. White ;
1 McGill University, Montreal, QC, Canada
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| Content: | Rats were adapted to drinking in a test cage on daily water deprivation schedules of 3 or 23 hr. They were then presented with a sweet, non-nutritive solution to drink followed immediately by an IP injection of LiCl or physiological saline. On a test trial 48 hr later the rats that received LiCl drank significantly less than the rats that received saline (a CTA) in both deprivation conditions, although total consumption was higher in the 23 hr than in the 3 hr group. During the consumption test USVs in the ranges of 20-22 KHz and 45-50 KHz were recorded. Previous research has associated vocalizations in the lower range with negative affect and those in the higher range with positive affect. Accordingly, a ratio of the number of calls in the high range divided by the total numbers of calls was used to estimate affective state. These ratios were not significantly different in the two deprivation conditions, even though total consumption differed. In both deprivation conditions the USV ratios were significantly lower in the LiCl group than in the saline group, suggesting that reduced consumption in the LiCl groups was accompanied by negative affect. In a second experiment, rats with lesions of the lateral amygdala (including lateral nucleus and the dorsolateral part of basolateral nucleus) failed to show a CTA in the 23 hr deprivation condition; USV ratios recorded during the test remained high, suggesting that the lesions may have blocked conditioned negative affect associated with the sweet solution during the training trial. In the 3 hr condition the lesions had no effect on the CTA and the USV ratios remained significantly depressed. (In a subsequent test these rats failed to acquire conditioned freezing.) This suggests that the decrease in consumption exhibited by these rats was due to a learning process other than amygdala-mediated conditioned aversion. |
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