Impairment of memory in a delayed non-matching to place task following mamillary body lesions in mice.
This study assessed the effects of a mamillary body (MM) lesion on memory measured in a delayed non-matching to place task performed in an 8-arm radial maze using BALB/c mice as subjects. In this task, the subjects had to recognize (test-phase) a non-visited arm from a previously visited arm (the sample-place) and were required to enter the non-visited arm in order to get reward. In the first experiment, the difficulty of the recognition was increased by interpolating forced visits (1 to 5; i.e. the study-phase) between the sample-place and the test-phase. In the second experiment, the number of interpolated visits which followed the study-phase was kept constant (5) but the sample-place was placed either before and after the interfering visits. Our results showed that MM subjects were dramatically impaired as compared to controls when required to recognize after 5 but not after 1 interpolated visits (first experiment). However, this deficit was observed only when the sample-place preceded but not when it followed the interpolated visits (second experiment). Our data emphasize the importance of the MM in memory and amnesia.
Beracochea
D J
DJ
Laboratoire de Psychophysiologie, UA C.N.R.S. 339, Université de Bordeaux I, Talence, France.
Alaoui-Bouarraqui
F
F
Jaffard
R
R
D000818:Animals; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D004193:Discrimination Learning / Q000502:physiology*; D008297:Male; D008326:Mammillary Bodies / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009949:Orientation / Q000502:physiology*; D012153:Retention, Psychology / Q000502:physiology