Preclinical animal anxiety research – flaws and prejudices

Abstract

The current tests of anxiety in mice and rats used in preclinical research include the elevated plus‐maze (EPM) or zero‐maze (EZM), the light/dark box (LDB), and the open‐field (OF). They are currently very popular, and despite their poor achievements, they continue to exert considerable constraints on the development of novel approaches. Hence, a novel anxiety test needs to be compared with these traditional tests, and assessed against various factors that were identified as a source of their inconsistent and contradictory results. These constraints are very costly, and they are in most cases useless as they originate from flawed methodologies. In the present report, we argue that the EPM or EZM, LDB, and OF do not provide unequivocal measures of anxiety; that there is no evidence of motivation conflict involved in these tests. They can be considered at best, tests of natural preference for unlit and/or enclosed spaces. We also argued that pharmacological validation of a behavioral test is an inappropriate approach; it stems from the confusion of animal models of human behavior with animal models of pathophysiology. A behavioral test is developed to detect not to produce symptoms, and a drug is used to validate an identified physiological target. In order to overcome the major methodological flaws in animal anxiety studies, we proposed an open space anxiety test, a 3D maze, which is described here with highlights of its various advantages over to the traditional tests.

Neuroprotective Effects of Pomegranate Peel Extract after Chronic Infusion with Amyloid-β Peptide in Mice

“…At the end of the infusion period, all animals, independent of treatment, showed a reduction in rearing, but not in the locomotor activity, which is attributable to the animal’s habituation to the equipment as can be observed for some behavioral equipments [26]. …”

Cigarette smoke exposure during adolescence but not adulthood induces anxiety‐like behavior and locomotor stimulation in rats during withdrawal

“…It can be argued that the ability to demonstrate anxiety‐like behavior in the EPM was limited due to the low values in the control rats. Several factors may influence the behavior of rats on the EPM including but not limited to lighting, animal handling, time of the test, the number of trials, and strain (Carobrez and Bertoglio, 2005; Ennaceur and Chazot, 2016). However, the values that we have obtained in the present study are consistent with previous studies utilizing similar subjects (SD rats) and EPM protocol (Elliott et al, 2004; Inostroza et al, 2011; Schmitt and Hiemke, 1998).…”

“…Affective withdrawal symptoms were assessed through the elevated plus-maze (EPM) test, open-field test (OFT), and the passive-avoidance task. The EPM is a widely used and accepted method to assess anxiety-like behavior in rodents (Carobrez and Bertoglio, 2005;Ennaceur and Chazot, 2016). Previous studies have shown that rats undergoing nicotine withdrawal demonstrate anxiety-like behavior in this test (Irvine et al, 2001;Manhaes et al, 2008;Wilmouth and Spear, 2006).…”

Slope climbing challenges, fear of heights, anxiety and time of the day

“…The elevated platform with downward slopes, unlike the plus-maze, light/dark box, and the open-field, does not provide a refuge or a shelter, which promote safety and security over risk taking [24,21]. The presence of protected/unlit spaces may reduce fear and anxiety [50]; the decision-making is simplified by the availability of the choice between an apparent safe place and an apparent aversive place.…”