Knowledge Base

Introduction

The Novel Object Recognition (NOR) test was first described by Ennaceur and Delacour (1988). Rats or mice are exposed first to two identical objects and then one of the objects is replaced by a new (novel) object. The time spent exploring each of the objects is measured. The test has become popular for assessing visual memory in rodents in general and to test the effects of amnesic drugs in particular.

The test is based on spontaneous behavior with no reinforcement such as food or shock. Non-amnesic animals will spend more time exploring the novel object than the familiar one. An absence of any difference in exploration time can be interpreted as a memory defect or, in case an amnesic drug is tested, a non-effective drug. This chapter describes how a NOR test can be conducted with EthoVision XT.

On the downloads section of the Noldus website my.noldus.com, you find a number of sample experiments, including one that features a NOR test.

The Sample Experiment

To see how a Novel Object Recognition test is carried out in EthoVision XT, see also the sample experiment Novel Object Recognition test XT180 on the downloads section of the Noldus website (my.noldus.com). Download this file and save it on your computer. In EthoVision XT, choose File > Restore Backup and select the file. For more information, see the document Description of sample experiments of EthoVision XT.pdf.

References

• Ennaceur, A.; Delacour, J. (1988) A new one-trial test for neurobiological studies of memory in rats, 1: Behavioral data. Behavioral Brain Research, 47-59.
• Benice, T.J.; Raber, J. (2008). Object recognition analysis in mice using nose-point digital video tracking. Journal of Neuroscience Methods, 422-430.
• McDowell, K.A.; Hutchinson, A.N.; Wong-Goodrich, S.J.E.; Presby, M.M.; Su, D.; Rodriguiz, R.M.; Law, K.C.; Williams, C.L.; Wetsel, W.C.; West, A.E. (2010). Reduced cortical BDNF expression and aberrant memory in Carf knock-out mice. The Journal of Neuroscience, (22), 7453-7465.
• Siegel, J.A.; Park, B.S.; Raber, J. (2011). Long-term effects of neonatal methamphetamine exposure on cognitive function in adolescent mice. Behavioural Brain Research, 159-164.
• Simmons, D.A.; Rex, C.S.; Palmer, L.; Pandyarajan, V.; Fedulov, V.; Gall, C.M.; Lynch, G. (2009). Up-regulating BDNF with an ampakine rescues synaptic plasticity and memory in Huntington's disease knock-in mice. PNAS, 4906-4911.

For a complete list of publications, see the results of Google Scholar.

Physical Setup

The following suggestions are specifically to optimize video tracking. For general information, see the section Physical Setup in the chapter The Open Field Test.

• The objects should contrast with the animal. If necessary use a different setup for light and dark colored animals.
• Make sure that the objects do not move due to the activity of the animal.
• Either make sure the sides of the box are not reflective (for example, sand the box to make it matte), or exclude the sides from the arena. If your objects are close to the sides, you will need to track the animal when it is against the side.

Source: EthoVision XT 18 - Application Manual, Noldus Information Technology