Fornix-fimbria section and working memory deficits in rats: stimulus complexity and stimulus size.
Rats were trained on delayed matching-to-sample (DMS) with goalboxes containing complex objects as stimuli. On reaching the preoperative learning criterion, the rats were allocated to conventional fornix-lesioned or control groups. In a series of postoperative DMS experiments, different kinds of stimuli were used, ranging from complex object boxes to large, simple black or white goalboxes, with 3 transitional types in between. Lesions impaired choice accuracy whenever the rats were tested with large, simple goalboxes, but not with smaller boxes of otherwise identical construction. A brief, final experiment showed no amelioration of the lesion-induced impairment when complex objects were added to large, simple goalboxes. The results are discussed in terms of spatial and nonspatial accounts of hippocampal function.
Cassaday
H J
HJ
Department of Experimental Psychology, University of Oxford, England.
Rawlins
J N
JN
D000818:Animals; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D004193:Discrimination Learning / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology; D051381:Rats; D012153:Retention, Psychology / Q000502:physiology; D012858:Size Perception / Q000502:physiology*