Using lorazepam to dissociate perceptual and conceptual priming in memory.
Date
2005
Authors
Thompson, Carol Elizabeth.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
To further the understanding of the relationship between perceptual and conceptual memory systems, the effects of lorazepam on perceptual and conceptual priming were examined in two studies. In Experiment One, 53 participants were randomly assigned to one of two drug conditions: 2mg of lorazepam (LZ) or placebo control (PB). After allowing time for lorazepam to reach peak concentration, every participant was tested on one conceptual (word association) and one perceptual (word identification) priming task. Results indicated that the LZ group was impaired (relative to the PB group) on perceptual priming, but not impaired on conceptual priming. In addition to the priming measures, secondary tasks indicated that the LZ group was impaired (relative to the PB group) on working memory (digit-symbol task) and attention (symbol-cancellation task). The LZ group also indicated higher levels of self-reported sedation (using visual analogue scales). Experiment Two replicated and extended those findings with an additional 39 participants randomly assigned to LZ and PB groups. Two conceptual (word association and category-instance generation) and two perceptual (word identification and word-fragment completion) priming tasks were used. A priming effect on the word association task was not replicated for either drug group. The lorazepam-induced impairment on the word identification task was replicated. The category-instance generation task demonstrated priming in both groups, but the level of priming was lower in the LZ group. The word-fragment completion task demonstrated no lorazepam-induced impairment on priming, but overall the lorazepam-treated participants performed at a lower level. Consistent with the existing benzodiazepine literature, lorazepam-treated participants also demonstrated impairments on working memory (the digit-symbol task), attention (the symbol-cancellation task), explicit narrative memory (logical memory task), and explicit episodic memory (free recall); and they indicated greater levels of self-reported sedation (using visual analogue scales). The conclusions from both experiments imply that lorazepam has a greater effect on perceptual than on conceptual priming tasks, implying some dissociation between the systems serving these two functions. However, the results also imply that instead of characterizing tasks dichotically (as either "perceptual priming" or "conceptual priming"), tasks might be better characterized as tapping both memory systems to varying degrees.
Thesis (Ph.D.)--Dalhousie University (Canada), 2005.
Thesis (Ph.D.)--Dalhousie University (Canada), 2005.
Keywords
Psychology, Psychobiology., Health Sciences, Pharmacology., Psychology, Cognitive.