Abstract.
Using adult Long-Evans male rats, this experiment compared spontaneous (assessed 15 days and 4.5 months after surgery) and amphetamine-induced (assessed from 4.5 months after surgery onwards; 1 mg/kg, i.p., ten injections, 48 h apart) locomotor activity following N-methyl-d-aspartate lesions of the entorhinal cortex, electrolytic lesions of the fimbria-fornix, or ibotenate lesions of the hippocampus. Sham-operated rats were used as controls. Hippocampal and fimbria-fornix lesions, but not entorhinal-cortex lesions induced diurnal and nocturnal hyperactivity, which was attenuated over time, but only in rats with fimbria-fornix lesions. Amphetamine-induced hyperlocomotion was assessed in a familiar environment. Lesions of the entorhinal cortex potentiated the locomotor effects of amphetamine, but not lesions of the hippocampus or interruption of the axons in the fimbria-fornix pathway. Sensitization appeared to be decreased by fimbria-fornix lesions and to be prevented by hippocampal lesions. Rats with entorhinal-cortex lesions behaved as if they had already been sensitized by the lesion. These results clearly show that lesions of the fimbria-fornix, the hippocampus, and of the entorhinal cortex have different effects on spontaneous and amphetamine-induced hyperactivity, as they also have on learning and memory tasks.
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Coutureau, E., Galani, R., Jarrard, L. et al. Selective lesions of the entorhinal cortex, the hippocampus, or the fimbria-fornix in rats: a comparison of effects on spontaneous and amphetamine-induced locomotion. Exp Brain Res 131, 381–392 (2000). https://doi.org/10.1007/s002219900301
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DOI: https://doi.org/10.1007/s002219900301