Translational Difficulties in Querying Rats on “Orientation”

Abstract

The aim of this study was to translate the “orientation” query of the ADAS-Cog inventory to rats and to investigate whether they can determine which time of the day they are. For this purpose, we established a modified Morris water-maze navigation task where the escape platform was placed onto various locations at different times of the day: “morning”, “noon” and “evening”. In each of these sessions rats swam a “query” trial and a “confirmatory” trial, 30 min apart. Lister Hooded rats randomly chose among the three possible target locations, while Long Evans rats partly followed a win-stay strategy by preferring to visit first to the platform position of the previous session. Despite simplifying the task to a morning–evening discrimination, Lister Hooded rats continued searching by chance, while Long Evans rats switched to the mentally less demanding random strategy. We then inserted a board into the pool which required longer swimming path from the animals when they were correcting an initial wrong choice, but this modification did not result in a change in the above strategies. Lastly, in a separate group of Long–Evans rats, the training conditions were modified inasmuch an incorrect choice was definitely punished by impeding the animals to correct it and confining them to a platform-free part of the maze for the whole trial period. However, even these stricter conditions were not sufficient to make the rats distinguish times of the day. The observed lack of time discrimination may source from an evolutionary built in mechanism characteristic for the rat species or this ability may have only been lost in laboratory rats.

Age-related decline of various cognitive functions in well-experienced male rats treated with the putative anti-aging compound (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine ((-)BPAP)

“…Animals were got acquainted with the MWM paradigm at the age of 8 months ( n = 13), 9.5 months ( n = 10), or 10.5 months ( n = 9). At the age of 18–19 months, they all went through a modified version of the task designed to measure a kind of episodic memory [ 42 ]. At age of 24 months, the animals performed the task several times within 2 weeks in the abovementioned serotonin 5-HT6 receptor antagonist study [ 10 ].…”

Lack of general learning ability factor in a rat test battery measuring a wide spectrum of cognitive domains

“…In the modified Morris water-maze navigation task, rats had to find the hidden platform by taking into account the actual time of the day [15]. The platform was placed into the north-west target zone at 6:00 AM ('morning') and into the south-west part of the maze at 2:00 PM ('evening').…”

“…Procedural learning and motor skills were tested in the in-house established pot jumping test (PJT) [14]. We also set up an episodic memory test (EPISM) by modifying the standard Morris water-maze procedure [15]. Beside the cognitive tasks, anxiety level of the animals was assessed in the elevated plus-maze (EPM) test [16].…”

Introduction of a pharmacological neurovascular uncoupling model in rats based on results of mice

“…We recently elaborated and established a rat cognitive test battery and testing protocol for more reliable prediction of clinical efficacy [5,18]. According to the protocol, several cognitive tasks representing different cognitive domains (for example, five-choice serial reaction time task (5-CSRTT) for attention, a cooperation task for social cognition [19], Morris water maze paradigm for spatial memory [20], pot-jumping exercise for procedural memory [21]) were taught to the same cohort of rats. Hereby we created a population with "widespread knowledge" and the effect of a particular impairment method on the various cognitive functions could be simultaneously measured in this population.…”