Stavisky RC, Ayers MR, Anthony MS, Hopkins WD, Andrews M, Kaplan JR. Assessment of cognitive performance in reproductively intact and ovariectomized monkeys. Am J Primatol. 1999;49(1):103.

Several lines of evidence suggest that cognition is affected by the actions of estrogen on ERb in the brain. However, to test this hypothesis in monkeys, traditional methods (e.g.WGTA) often require isolated animals and food or water deprivation, which may induce stress and negatively influence cognition; furthermore, such an approach is time and labor intensive, and only permits the testing of a few individuals. In this study we investigated the utility of the Language Research Center computerized cognitive testing to assess the effect of endocrine status (Ovariectomized vs. Intact) on transfer of learning ability in cynomolgus monkeys. Microchip identification permitted the simultaneous training of multiple animals in their homepen. Testing was conducted on individual animals in their pens (with penmates removed) for two-hour daily bouts. All animals (n = 5) completed the training tasks, and a subset of animals tested (n = 4) accomplished the test (Transfer Index) after three weeks. The initial results were sufficient to establish the animal numbers necessary for statistical analyses. Data (ovx = 42.09 %, intact = 44.82 %, pooled sd = 3.4) indicated that to determine a 10% difference between endocrine states with 80% power, a = 0.0 5, 10 animals per group are necessary. These results suggest that evaluation of the influence of estrogen on cognitive performance requires relatively small numbers of animals and can be accomplished without deprivation or undue stress.