| Abstract: | In Experiment 1 of this report, we examined the neuropharmacological nature of short-term working memory of rats trained to retrieve food from all arms of a 12-arm radial maze. Delay intervals of varying length were placed between Choices 6 and 7. Lanthanum (LaCl?) and glutamate (GLU) injected bilaterally into the hippocampus effectively impaired retention over short delay intervals, which suggests a possible role for calcium and/or potassium and for glutamate in working memory. However, another equally likely explanation for the amnesic effects of LaCl? and GLU is that these drugs impaired reference memory. To test more directly the hypothesis that LaCl?, GLU, or ANI might differentially affect working and reference memory, we tested the effects of these drugs on performance of rats trained to retrieve food from only 8 arms of the 12-arm maze in Experiment 2. The remaining 4 arms were never baited, in order to test reference memory function. We predicted that rats would make errors only in baited arms (i.e., errors of working memory). Instead, results of Experiment 2 showed that LaCl?, GLU, or ANI injection produced errors in unbaited arms even before a 120-min delay. If rats were injected with LaCl? or GLU, baited-arm errors were observed only after the delay period. No impairment of performance on baited arms were observed after injection of ANI. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
