ADHD Research Today is a free monthly online journal that collates and summarizes the latest research about ADHD, including details on attention-deficit hyperactivity disorder, drugs, treatment, symptoms.

Spontaneously hypertensive, Wistar-Kyoto and Sprague-Dawley rats differ in performance on a win-shift task in the water radial arm maze.

Clements KM, Wainwright PE

Department of Psychology, University of Waterloo, Waterloo, Ont., Canada N2L 3G1. kmfrisa@uwaterloo.ca

The spontaneously hypertensive rat (SHR) is a commonly used animal model of attention deficit hyperactivity disorder. Previous literature is inconclusive with respect to the exact nature of memory impairments in this strain. The objective of this study was to assess spatial memory as measured by performance of male SHR, Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats on a win-shift version of the water radial arm maze. On this task, all strains made more errors on Trial 4 when the mnemonic demand was highest, and showed a similar response when the delay was increased from 60s to 2h on Week 3. Both SHR and WKY rats made more reference memory errors than SD, however, SHR showed minimal improvement over weeks. The increase in errors may be due to a greater inclination of SHR and WKY to use a chaining strategy of entering consecutive arms than SD. Furthermore, the number of incomplete arm entries into reference memory arms decreased over weeks in WKY and SD, but increased in SHR, suggesting increased impulsivity of SHR at the later stages of testing. Although based on number of errors, the data indicate that SHR may have memory deficits, the data relating to arm entries suggest that the minimal improvement in SHR over weeks may have been due to greater impulsivity in the later weeks, rather than defective memory. Thus, these findings are consistent with SHR having impairments with selection of appropriate behavioural responses in a goal-directed task.

Published 23 January 2006 in Behav Brain Res, 167(2): 295-304.
Full-text of this article is available online (may require subscription).

© 2004-2008 ADHD Research Today. All Rights Reserved.