Details

Autor(en) / Beteiligte

• Akkerman, Sven
• Blokland, Arjan
• Reneerkens, Olga
• van Goethem, Nick P.
• Bollen, Eva
• Gijselaers, Hieronymus J.M.
• Lieben, Cindy K.J.
• Steinbusch, Harry W.M.
• Prickaerts, Jos

Titel

Object recognition testing: Methodological considerations on exploration and discrimination measures

Ist Teil von

• Behavioural brain research, 2012-07, Vol.232 (2), p.335-347

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2012

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• ► Pre-experimental training prevents stress and habituation biases. ► No relation was found between sample trial exploration and memory performance. ► Test trail exploration was positively correlated to absolute discrimination measures. ► Relative discrimination measures were unaffected by test trial exploration levels. ► Wistar rats remembered object information for 9 days after a single 3min exposure. The object recognition task (ORT) is a popular one-trial learning test for animals. In the current study, we investigated several methodological issues concerning the task. Data was pooled from 28 ORT studies, containing 731 male Wistar rats. We investigated the relationship between 3 common absolute- and relative discrimination measures, as well as their relation to exploratory activity. In this context, the effects of pre-experimental habituation, object familiarity, trial duration, retention interval and the amnesic drugs MK-801 and scopolamine were investigated. Our analyses showed that the ORT is very sensitive, capable of detecting subtle differences in memory (discrimination) and exploratory performance. As a consequence, it is susceptible to potential biases due to (injection) stress and side effects of drugs. Our data indicated that a minimum amount of exploration is required in the sample and test trial for stable significant discrimination performance. However, there was no relationship between the level of exploration in the sample trial and discrimination performance. In addition, the level of exploration in the test trial was positively related to the absolute discrimination measure, whereas this was not the case for relative discrimination measures, which correct for exploratory differences, making them more resistant to exploration biases. Animals appeared to remember object information over multiple test sessions. Therefore, when animals have encountered both objects in prior test sessions, the object preference observed in the test trial of 1h retention intervals is probably due to a relative difference in familiarity between the objects in the test trial, rather than true novelty per se. Taken together, our findings suggest to take into consideration pre-experimental exposure (familiarization) to objects, habituation to treatment procedures, and the use of relative discrimination measures when using the ORT.