Activity, startle magnitude, and prolonged food and water deprivation: Two further failures to duplicate

Abstract

Studies from one laboratory have shown deprivation-induced attenuation of startle response magnitudes, but another laboratory has reported failures to show any relationship between these variables. In an attempt to locate possible procedural contributions to this discrepancy in outcomes, our Experiment 1 involved 20 massed startle-stimulus presentations (30-sec ISI) to rats that had gone either 43 h or 1 h since eating (80% body weights equated for groups). Experiment 2 entailed spaced presentations (four trials per five bidaily sessions, 20-min ISI) to rats that had gone either 43 h or 1 h since drinking (80% weights also equated). Activity prior to, during, and after startle presentations also was recorded. Although group startle magnitudes differed on some trial blocks of both experiments, these differences were not systematically related to either of the deprivation conditions. Mean activity level was sensitive to startle-stimulus presentations, and showed systematic trial-block rates of decline for periods prior to, during, and following startle presentations that were identical for all groups.