Selective neurodegeneration of hippocampus and entorhinal cortex correlates with spatial learning impairments in rats with bilateral ibotenate lesions of ventral subiculum.

Rats with bilateral ibotenic acid lesions of ventral subiculum were tested in an eight-arm radial maze task for spatial learning and memory functions. The performance of the lesioned rats was severely impaired relative to control rats in both acquisition and retention of the spatial task. Following subicular lesions, profound neurodegeneration of the CA1 and CA3 sub sectors of hippocampus and entorhinocortical layers I, II, III, V and VI was observed. These results support the concept that neurons in the ventral subiculum are a part of the neural network along with the above neurons, which could be involved in the processing of spatial information.