Choice behavior of fornix-damaged rats in radial maze error-free situations and subsequent learning.
Fornix-damaged, sham-operated, and control rats were placed in a radial eight-arm maze for fixed series of runs with either a 0% or a 100% reinforcement schedule in order to study their choice behavior independently from any learning problem. Subsequently, the ability to learn the radial maze task was examined as a function of the exploratory patterns developed in each error-free situation. The results showed that the continuous absence or presence of food in the radial maze induced two distinct models of exploration in sham-operated and control rats: choice alternation in the absence of food and perseveration in the presence of food. Conversely, this dichotomy did not occur in fornix-damaged rats that run approximately the same number of paths in both error-free situations, but made fewer different path choices in the 0% reinforcement condition and more different path choices in the 100% reinforcement condition than controls. When submitted to the radial maze task, a positive transfer was observed in all groups from the error-free situation in which the rats run more different paths: from the 0% reinforcement situation for controls and from the 100% reinforcement situation for the lesioned rats. These data indicate that damaging the septo-hippocampal pathway modifies spontaneous choice behavior through a different response to specific reinforcement programs but does not prevent the memorization and the transfer of information from error-free to learning situations.
Ammassari-Teule
M
M
Istituto di Psicobiologia e Psicofarmacologia, Rome, Italy.
Maho
C
C
D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology*; D001931:Brain Mapping; D004193:Discrimination Learning / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule; D012153:Retention, Psychology / Q000502:physiology