Year: 2006
Type: dissertation
Abstract: Previous research has indicated that the amygdala exerts a modulatory influence on\nmultiple memory systems. Evidence also indicates that emotional state can influence the\nuse of multiple memory systems and that this effect is mediated by the amygdala.\nAnxiogenic drugs administered during acquisition in a task that can be acquired either\nthrough hippocampus-dependent “place” learning or caudate dependent “response”\nlearning, resulted in the predominant use of response learning. It is not known whether\ninducing anxiety at other behavioral time points will also influence the relative use of\nmultiple memory systems. In experiment 1, male Long-Evans rats were trained to swim\nfrom the same start point to an escape platform constantly located in a goal arm. Prior to\nmemory retrieval rats were administered either alpha- two adrenoceptor antagonist RS\n79948-197, peripherally (0.03, 0.01, 0.3 mg/kg) or into the basolateral amygdala (0.1 µg),\nor saline vehicle. Rats treated with RS 79948-197 prior to memory retrieval exhibited\ncaudate-dependent response learning.\nPrevious studies examining the effects of RS 77948-197 on memory were conducted\nwith rats trained in an anxiogenic state and subsequently probed in a drug free state.\nExperiment 2 examined whether state dependency may account for those results.\nAnimals received peripheral (0.1 mg/kg) or intra-amygdala (0.1 µg) administration of RS 79948-197, prior to both acquisition and memory retrieval. Rats treated with RS 79948-\n197 predominantly exhibited response learning.\nFinally, experiments 3 and 4 examined whether the use of response learning\nproduced by RS79948-197 was due to the impairing effect on hippocampus-dependent\nmemory. Rats that were administered peripheral (0.03 mg/kg) or intra-amygdala (0.1 µg)\ninjections of RS 79948-197 displayed impaired acquisition of the single solution place\ntask relative to control animals. This indicates that place learning was impaired.\nOver, all the present findings indicate 1) peripheral and intra-amygdala anxiogenic drug\nadministration results in the use of habit memory at both acquisition and retrieval, 2)\nstate dependency does not play a role in the influence of RS 799948-197 on memory\nsystem use, 3) the use of response learning produced by peripheral and intra-amygdala\ninjections of RS 79948-197 may result from an impairing effect of hippocampusdependent\nmemory.
Author: Audrea E. Elliott
Language: English
Topic: Memory and Neural Mechanisms
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2302961428