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Neonate rats demonstrate high levels of retention for odour preference when a substantially reduced training trial of two minutes is used

Published online by Cambridge University Press:  01 January 2023

RP Ogeil*
Affiliation:
School of Psychology, Psychiatry & Psychological Medicine, Monash University, Clayton, VIC 3800, Australia
TM Edwards
Affiliation:
School of Psychology, Psychiatry & Psychological Medicine, Monash University, Clayton, VIC 3800, Australia Tabor College, 222 Oban Road, PO Box 2223, Ringwood North, VIC 3134, Australia
*
* Contact for correspondence and requests for reprints: Rowan.Ogeil@med.monash.edu.au

Abstract

Neonate rats have played an important and unique role within the memory literature. Specifically, they are relatively naïve to experience, can be trained in an ethologically-valid way, using a single trial, which is not aversive and can demonstrate retention for at least 24 h, post-training. As such, they have provided salient insights into the biological mechanisms underlying the memory trace and brain development. The task of choice for rat pups is one using odour preference requiring the removal of each pup from the nest/dam for a ten-minute training trial. For such young animals this may reasonably lead to undue stress and the potential of subsequent rejection by the dam. Little research has considered whether the training duration could be substantially shortened to provide significant animal welfare benefits while maintaining, if not improving, task efficacy. This issue was addressed in the current paper using six-day old Wistar rats (n = 175) exposed to a single-trial, odour-preference task using either a standard ten-minute training trial or a shorter two-minute training trial. Exposing rat pups to the training odour for two minutes did not compromise the level of discrimination observed at test 24 h later. This finding suggests that significantly shorter training trials can be used without compromising retention levels at test. This not only has obvious welfare benefits, but may reasonably be considered to reduce pups’ stress levels which are known to alter both the strength and timing of the memory trace.

Type
Research Article
Copyright
© 2009 Universities Federation for Animal Welfare

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