Testing the spatial- versus object-learning distinction: water-maze performance of male rats exposed to ethanol during the brain growth spurt.
This study investigated the effects of exposure to ethanol during the brain growth spurt on a visual-discrimination (VD) and a place-learning task (PL) using intra-maze cues in the water maze. Artificially reared male Long-Evans rats were exposed to ethanol (ET) in a binge pattern from postnatal days 6-9 (6.5 g kg(-1) x day(-1); BAC approximately 330 mg/dl) or an isocaloric maltose-dextrin solution (gastrostomy control). A third suckled control group was reared by lactating dams. In experiment 1, rats were trained to discriminate horizontal- (H) versus vertical-striped (V) cues, with the positive cue providing escape from water. Groups did not differ with V+, but ET rats made more errors with H+. In experiment 2, the ET group was impaired in learning the spatial location of a submerged platform relative to intra-maze cues. In both tasks, acquisition deficits among ET rats were characterized by impairment emerging at trial 2, with intact reference memory on trial 1, and the ET group reached a comparable level of performance to controls by the end of training. In summary, because impairment was related to task characteristics, a clear distinction between impaired spatial- versus cue-based learning was not supported. However, these findings do support an effect of exposure to ethanol during the brain growth spurt on recent event, but not reference, memory.
Girard
Todd A
TA
Department of Psychology, University of Waterloo, Waterloo, Ont, Canada N2L 3G1. tagirard@uwaterloo.ca
Wainwright
Patricia E
PE
D000818:Animals; D001835:Body Weight / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000254:growth & development*; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003463:Cues; D004192:Discrimination, Psychological / Q000187:drug effects / Q000502:physiology; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology; D011247:Pregnancy; D051381:Rats; D020318:Rats, Long-Evans; D013028:Space Perception / Q000187:drug effects / Q000502:physiology*
D002492:Central Nervous System Depressants; D000431:Ethanol