The elevated gradient of aversion: a new apparatus to study the rat behavior dimensions of anxiety, fear, and impulsivity

Abstract

Few behavioral tests allow measuring several characteristics and most require training, complex analyses, and/or are time-consuming. We present an apparatus based on rat exploratory behavior. Composed of three different environments, it allows the assessment of more than one behavioral characteristic in a short 3-min session. Factorial analyses have defined three behavioral dimensions, which we named Exploration, Impulsivity, and Self-protection. Behaviors composing the Exploration factor were increased by chlordiazepoxide and apomorphine and decreased by pentylenetetrazole. Behaviors composing the Impulsivity factor were increased by chlordiazepoxide, apomorphine, and both acute and chronic imipramine treatments. Behaviors composing the Self-protection factor were decreased by apomorphine. We submitted Wistar rats to the open-field test, the elevated-plus maze, and to the apparatus we are proposing. Measures related to exploratory behavior in all three tests were correlated. Measures composing the factors Impulsivity and Self-protection did not correlate with any measures from the two standard tests. Also, compared with existing impulsivity tests, the one we proposed did not require previous learning, training, or sophisticated analysis. Exploration measures from our test are as easy to obtain as the ones from other standard tests. Thus, we have proposed an apparatus that measured three different behavioral characteristics, was simple and fast, did not require subjects to be submitted to previous learning or training, was sensitive to drug treatments, and did not require sophisticated data analyses.

Comparison of female and male behavior in the elevated gradient of aversion

“…Impulsivity may involve lack of control, while self-protection may involve anxiety and/or fear. These factors were confirmed by comparison with the behavior of rats in other apparatuses (open-field and elevated plus-maze) and with the use of drugs affecting behavior (1).…”

“…We have recently reported a new apparatus for scoring rat behavior in a novel environment (1). A factorial analysis indicated rat behavior is grouped into three factors: exploration, impulsivity, and self-protection.…”

Evaluation of the anxiolytic effects of acute administration of Passiflora alata extract in wistar rats submitted to swimming

“…Thus, when exposed to a new situation, a rodent would explore new environments, conflicting with the fear of heights and the aversion to closed arms. Thus, the avoidance of the open arm would be indicative of anxiety (Arantes et al, 2013;Campos et al, 2013;Kraeuter et al, 2019;Padurariu et al, 2017;Rico et al, 2019;Verbitsky et al, 2020).…”

Global Cerebral Ischemia in Male Long Evans Rats Impairs Dopaminergic/ΔFosB Signalling in the Mesocorticolimbic Pathway Without Altering Delay Discounting Rates

“…Due to growing literature replicating such results, it has been hypothesised in recent years that this could be indicative of decreased inhibitory control, possibly reflecting behavioural impulsivity ( Knowles et al, 2016 ; Morin et al, 2021 ). Previous studies have interpreted increased open-arm time in the EPM and decreased latency to the centre of the OFT as potential indicators of impulsivity ( Ueno et al, 2002 ; Binder et al, 2004 ), although this interpretation requires further investigation ( Rico et al, 2019 ). In the present study, disinhibition was less pronounced than in previous assessments, possibly due to extensive handling of these animals over days related to the DD task.…”

“…It is important to note that the EPM is classically known to measure anxiety-like behaviours, and that the interpretation of behavioural disinhibition in ischemic rodents remains novel. As such, the use of other measures and behavioural tests, such as the 5-CSRTT or the newly designed Elevated Gradient of Aversion ( Rico et al, 2019 ), could allow better elucidation of the subtypes of impulsivity impacted by GCI.…”