title: Strain differences in a high response-cost daily time-place learning task.
abstract: Previous research has shown that rats, unlike birds, do not readily demonstrate daily time-place learning (TPL). It has been suggested, however, that rats are more successful at these tasks if the response cost (RC) is increased. Widman et al. (2000) found that female Sprague Dawley (SD) rats learned a daily TPL task in which they were required to climb different towers depending on the time of day to find a food reward. Using a similar apparatus, we found that male SD rats learned the task, while male Long Evans rats did not. While all rats quickly learned to restrict the majority of their searching to the two towers that provided food, only the SD rats learned to go to the correct location at the correct time of day. Thus, there appears to be a strain difference in the effectiveness of a high RC task to promote learning. Tests of the timing strategies used revealed individual differences with one rat using a circadian strategy and another using an ordinal strategy. Post criterion decrements in performance did not allow sufficient testing to determine the timing strategies of the remaining rats. Possible interactions between strain, response cost, species typical behaviors and dependent measures are discussed.
authors.affiliation: Department of Psychology, Memorial University of Newfoundland, St. John’s, NL, Canada. cthorpe@mun.ca
authors.forename: Christina M
authors.initials: CM
authors.lastname: Thorpe
authors.forename: Scott H
authors.initials: SH
authors.lastname: Deibel
authors.forename: Jacinta I
authors.initials: JI
authors.lastname: Reddigan
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Fontaine
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004193:Discrimination Learning / Q000502:physiology; D005260:Female; D018782:Maze Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013997:Time Factors