Turchi JN, Saunders RC, Mishkin M (2002) Effects of cholinergic deafferentation of rhinal cortex on visual recognition in monkeys. Neuroscience 2002 Abstracts 82.5. Society for Neuroscience, Orlando, FL.
Summary: Excitotoxic lesions of the rhinal (perirhinal/entorhinal) cortices yield substantial deficits in visual recognition (Baxter and Murray, 2001; Malkova et al., 2001). To evaluate the mnemonic role of cholinergic inputs to this region, we compared the visual recognition performance of untreated monkeys with that of monkeys given rhinal cortex infusions of the selective cholinergic immunotoxin ME20.4-SAP. This toxin binds to the p75 receptor, borne by corticopetal cholinergic neurons of the basal forebrain, and is retrogradely transported to the cell body where it permanently destroys ribosomal function. Both groups were first trained to criterion in the rule for delayed nonmatching-to-sample (DNMS) with trial-unique stimuli at a 10-s delay in a Wisconsin General Testing Apparatus. This was followed by treatment and recovery for the experimental group (n=3) and an equivalent rest period for the control group (n=4), after which both groups were retrained on the DNMS rule and then given a memory performance test with increasing delays (30, 60, and 120 s) and list lengths (3, 5, 10, and 20 stimuli). The experimental group relearned the DNMS rule without significant impairment but then demonstrated robust deficits when tested with increasing delays (a mean of 83% vs 95% for controls) and list lengths (67% vs 86% for controls). The findings complement results obtained in a study of muscarinic receptor blockade in the perirhinal cortex (Tang et al., 1997) and indicate that cholinergic integrity of the rhinal cortex is critical for visual recognition memory.
Related Products: ME20.4-SAP (Cat. #IT-15)