Recently neurotoxic lesions of limbic structures in rodents have been introduced as models of schizophrenia. Especially the dysfunction of the hippocampus may be enroled in the key deficits seen in schizophrenic patients. As the main effects of the disease develop after puberty time dependent deficits after neurotoxic lesions of the hippocampus were investigated in this experiment.
Two experimental groups of animals were compared, one receiving an early bilateral hippocampal damage by kainic acid injections into the ventral hippocampus one week after birth (PD7), while the other group received neurotoxic lesions two months after birth (PD60). Control animals reveived vehicle injections into the ventral hippocampus one week or two months after birth. Spatial memory of the animals was tested in a Morris water-maze. Additionally exploratory behavior and locomotor activity were tested in a test- battery 3, 4 and 5 months after birth.
Lesioned animals showed significant deficits to find the hidden platform in the Morris maze in comparison with controls. Spatial memory deficts did not differ significantly between PD7 and PD60 animals. Subjects with early hippocampal lesions (PD7) showed a more extensive exploratory behavior in a novel environment compared to PD60 animals and controls.
The results correspond to earlier reports describing an increased motor activity in a novel environment after neurotoxic lesions of the hippocampus. The postpubertal development of the deficits corresponds to the late onset of key symptoms in schizophrenia.
Poster in der Gruppe Physiologische Psychologie, Mittwoch, 31. März 1999, 17:00-19:00, Foyer 2. Stock
