Timed active avoidance learning in lurcher mutant mice.
Lurcher mutant mice (+/Lc) which exhibit a massive loss of neurons in the cerebellar cortex and in the inferior olivary nuclei were subjected to an active avoidance learning task; the animals' avoidance response must occur within a small time window after a short or a long delay. The control mice needed a mean of 8.3 sessions of 10 trials (short delay group) and of 11.8 sessions (long delay group) and showed good retention after a 24 h interval. When subjected to the same number of sessions, the +/Lc mice were unable to learn the timing task. However, a subgroup of lurcher mutants was able to learn after a high number of sessions (25.4 sessions as a mean). There was no intergroup difference in the standard version of one-way active avoidance. These results indicate that the cerebellar cortex is involved in time processing during active avoidance. The cerebellum may be part of a loop including the cerebral cortex known to be involved in time perception. An alternative explanation is that the cerebellar mutant animals had persevering tendencies acquired during performance of the one-way avoidance task.
Monfort
V
V
Université de Rouen, Faculté des Sciences, Laboratoire de Neurobiologie de l'Apprentissage, Mont-Saint-Aignan, France.
Chapillon
P
P
Mellier
D
D
Lalonde
R
R
Caston
J
J
D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D002525:Cerebellar Cortex / Q000033:anatomy & histology / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D008297:Male; D008568:Memory / Q000502:physiology; D051379:Mice; D008818:Mice, Neurologic Mutants; D009154:Mutation; D010056:Overlearning / Q000502:physiology; D013998:Time Perception / Q000502:physiology*