Stress-induced disturbances in Morris water-maze performance: interstrain variability.
Marked differences were observed across strains of mice (i.e., DBA/2J, C57BL/6J, BALB/cByJ and CD-1 mice) in acquisition, performance and reversal of a place learning response in a Morris water-maze. While DBA/2J, C57BL/6J and CD-1 mice typically learned the response readily, only 20% of BALB/cByJ mice acquired the response. Commensurate with the effects of hippocampal disturbances, the performance deficits in BALB/cByJ mice were not evident when the position of the platform in the water-maze was cued. Exposure to uncontrollable foot shock did not affect the acquisition or performance of this response in the former three strains, but provoked a modest disruption of reversal performance in DBA/2J mice and markedly impaired reversal performance in BALB/cByJ mice. It seemed, however, that the response strategies adopted in these strains could be distinguished from one another. In the reversal paradigm BALB/cByJ mice initially persisted in returning to the original training quadrant rather than to the new goal quadrant. Following 2 days of training the perseveration was no longer apparent and animals seemed to adopt a random search strategy. In contrast, DBA/2J mice, which exhibited a smaller stress-induced disturbance, did not display a perseverative response style. These data suggest that inescapable shock does not disturb response-outcome associations, but may result from the induction of a perseverative response style. However, it appears that the mechanisms responsible for an interference of performance may not be uniform across strains.(ABSTRACT TRUNCATED AT 250 WORDS)
Francis
D D
DD
Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Verdun, Québec, Canada.
Zaharia
M D
MD
Shanks
N
N
Anisman
H
H
D000818:Animals; D001143:Arousal / Q000235:genetics* / Q000502:physiology; D001245:Association Learning / Q000502:physiology; D003463:Cues; D004193:Discrimination Learning / Q000502:physiology; D004597:Electroshock; D004924:Escape Reaction / Q000502:physiology*; D005239:Fear / Q000502:physiology; D005838:Genotype; D005938:Glucocorticoids / Q000502:physiology; D006380:Helplessness, Learned; D006624:Hippocampus / Q000502:physiology; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D012193:Reversal Learning / Q000502:physiology; D013045:Species Specificity
D005938:Glucocorticoids