Saul, R.D., Wiest, M.K., & Brady, A.M.  (2006, October).  Spatial working memory deficits in the neonatal ventral hippocampal lesion rat model of schizophrenia.  Poster session to be presented at the Society for Neuroscience Annual Meeting, Atlanta, GA.

Abstract

Patients with schizophrenia have deficits in spatial working memory, a function dependent on the hippocampus and its target structures.  Post-mortem analyses of schizophrenic brains have shown pyramidal cell disarray in the hippocampus.  We used the neonatal ventral hippocampal lesion (NVHL) rat model of schizophrenia to determine if spatial working memory is disrupted in a radial arm maze task.  In the non-delayed random foraging (NDRF) task, rats were required to forage for sucrose pellets in 4 arms of the 8-arm maze without re-entering any arms.  Rats were also tested for prepulse inhibition (PPI) of the acoustic startle response.  Lesioned and sham-treated rats acquired the NDRF task in the same number of days, and did not differ on any behavioral measures on this task.  However, lesioned rats exhibited a deficit in PPI, indicating impaired sensorimotor gating.  These results suggest that the NVHL model reproduces some of the working memory and sensorimotor gating abnormalities observed in patients with schizophrenia.  However, spatial navigation impairments may be limited to task conditions which place higher demands on working memory.