Resumo

RIBES INESTA, Emilio; ARENAS, Sergio  e  MAYORAL, Alfredo. Relationship between different local densities of water and local densities of responses on the overall frequency of responding in a signaled temporal Schedule. Acta comport. [online]. 2012, vol.20, n.2, pp.127-141. ISSN 0188-8145.

An experiment was conducted with eight male albino Wistar rats. It was compared the effect of delivering water in the twenty initial or final cycles or when distributed every third cycle of a temporally defined schedule upon the total number of responses per session. Water delivery was contingent to the first response during the t^D period of each 60 s cycle and, in addition to that, if the rats did not respond, water was dispensed at the end on the first or final 20 cycles in two of the experimental, or in every third cycle in other three phases. t^D and t^Δ periods were signaled by different exteroceptive stimuli. Rats were distributed in two groups, exposed to the same experimental conditions, except for the fact that rats in one group had a retractable lever that was withdrawn during t^D after the first response, in those selected cycles in which non contingent water delivery was also scheduled. Results of the experiment showed similar response frequencies in both periods of the T cycle, a larger number of responses in the group with normal, non-retractable lever, and a high percentage of obtained contingent-water deliveries, suggesting that overall frequency of responses was a function of overall frequency of water deliveries, irrespectively of its allocation during the session.

Palavras-chave : local density of water; local density of responses; temporal schedules; retractable lever; percentage of obtained water deliveries.

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