Research Report Extensive spatial training does not negate age differences in response latency Pria M.D. Nippak a, ⁎ , C. Ikeda-Douglas b , Norton W. Milgram a a Institute of Medical Science, Division of Life Sciences, University of Toronto, 1265 Military Trail, Scarborough, ON, Canada M1C 1A4 b Department of Pharmacology, Division of Life Sciences, University of Toronto, 1 King's College Circle, ON, Canada M5S 1A8 ARTICLE INFO ABSTRACT Article history: Accepted 2 November 2005 Available online 7 February 2006 Previously, Nippak et al. [Nippak, P.M.D., Chan, A.D.F., Campbell, Z., Muggenburg, B., Head, E., Ikeda-Douglas, C., Murphy, H., Cotman, C.W., Milgram, N.W., 2003. Response latency in the canine: mental ability or mental strategy? Behav. Neurosci. 117 (5), 1066–1075] reported that young dogs respond significantly slower than aged dogs during the acquisition of a three-component delayed non-match to position (3-DNMP) task. Thus, we examined how age influences response latency (RL) when animals are trained extensively on the 3-DNMP task. Animals were separated into two groups based on their task sophistication. The first group comprised young (N = 5) and aged (N = 10) dogs that received extensive spatial training on a two-component delayed non-match to position task (2-DNMP) before 3-DNMP testing, while the second group of young (N = 8) and aged (N = 11) animals received extensive training on a variety of other non-spatial cognitive tasks between each 3-DNMP test period. RL age differences were absent following extensive 3-DNMP testing; however, other age-dependent performance differences emerged: all young animals learned the task and displayed RL slowing and superior response accuracy (RA) on the center-incorrect (CI) subtest, while several aged animals failed to learn the task and displayed no RL or RA subtest variations even when they acquired the task. Toates's [Toates, F., 1998. The interaction of cognitive and stimulus–response processes in the control of behaviour, Neurosci. Biobehav. Rev. 22 (1), 59– 83] theory of RL and mental strategy was proposed to explain these age differences in response strategies: the fast-responding aged animals utilized stimulus–response strategies, while the slow-responding young animals adopted cognitive strategies, a specific requirement for solving the CI subtest. © 2005 Elsevier B.V. All rights reserved. Keywords: Spatial learning and memory Delayed non-match to sample task Stimulus–response strategy Cognitive strategy Canine 1. Introduction Both learning and memory can benefit from task experience (Bors and Forrin, 1995; Burwell and Gallagher, 1989; Burwell et al., 1992; Gallagher et al., 1993, 1994; House and Zeaman, 1961; Jenson, 1982; Salthouse, 1991). Repeat testing and extended within-session training have been shown to improve task acquisition and enhance learning in novel environments (Baltes et al., 1988a,b; Hofland et al., 1981; Rogers and Fisk, 1991; Salthouse, 1991) across multiple behavioral measures (Bachevelier, 1993; Salthouse, 1991). Furthermore, repeated practice and/or extended test expo- sure can reduce or eliminate age-associated variation in learning and memory (Baltes et al., 1988a,b; Dulaney and BRAIN RESEARCH 1070 (2006) 171 – 188 ⁎ Corresponding author. Fax: +1 416 724 7684. E-mail address: pria.nippak@utoronto.ca (P.M.D. Nippak). 0006-8993/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2005.11.026 available at www.sciencedirect.com www.elsevier.com/locate/brainres