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.
Department of Psychology, University of Waterloo, Waterloo, Ont, Canada N2L 3G1. tagirard@uwaterloo.ca
Todd A
TA
Girard
Patricia E
PE
Wainwright
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