Development of post S and post non S DRL performance and its retention following septal lesions in rats

Absence of temporal discrimination following septal lesions

“…In contrast to the earlier reports of Ellen et aI (1964) and MacDougall et al (1969). only the normal animals in the present study showed evidence of temporal discrimination, as measured by the IRTs/OP statistic (Fig.…”

“…Two findings in the present study differ from previously reported results (Ellen et al, 1964;MacDougall et al, 1969). First, septal animals failed to acquire a temporal discrimination.…”

“…Previous studies (Ellen, Wilson, & Powell, 1964;MacDougall, VanHoesen, & Mitchell, 1969) have shown that, when interresponse times (IRTs) of septal animals barpressing on a DRL (differential reinforcement of low rates) schedule are converted to IRTs/opportunity (Anger, 1956), response probability increases as a function of the delay since the preceding response. The IRTs/OP is defined as the number of times an animal made a given delay divided by the number of occasions the animal actually delayed that long or longer, and is an unbiased estimate of response probability for equal IRT categories.…”

Behavioral perseveration: lesions of the septal nuclear complex and ventromedial hypothalamic nucleus

“…On the other hand, Ellen, Wilson, and Powell (1964) reported that septal rats were impaired in DRL response acquisition when food reinforcement was used, a finding supported by the data of Burkett andBunnell (1966), andMacOougall, Van Hoesen, and. A detailed analysis of septal behavior during DRL acquisition (MacDougall, Van Hoesen, and Mitchell, 1969) suggested that septal lesions disrupt the behavioral sequence that usually develops to fill the interval between responses.…”