Basal anxiety during an open field test is correlated with individual differences in contextually conditioned fear in mice

Abstract

Fear conditioning has been used to study pathogenic mechanisms underlying anxiety disorders. Several studies have shown that humans with anxiety disorders exhibit strong fear responses during the acquisition of conditioned fear. However, there have been no studies investigating whether basal anxiety within the normal range is related to conditioned fear in rodents. We hypothesized that individual differences in conditioned fear are correlated to the basal anxiety level of each individual. To test this hypothesis, we measured the basal anxiety of mice by using the elevated-plus maze (EPM) and open field test (OFT) and correlated these data with contextual freezing during contextual fear conditioning (CFC). Strong correlation was found between the basal anxiety level measured in the OFT and contextual freezing in the CFC. Baseline freezing was also strongly correlated with the contextual freezing level during the retrieval phase of CFC. However, the basal anxiety level measured in the EPM was correlated neither with conditioned fear nor with baseline freezing in the CFC. These results suggest that both basal anxiety in the OFT and baseline freezing are related to contextually conditioned fear.

D1 receptors in the anterior cingulate cortex modulate basal mechanical sensitivity threshold and glutamatergic synaptic transmission

“…In the published literature there is a poor correlation between performance in the OFT and EPM test, while EPM and DLET exhibit a greater correlation [72]. In addition, OFT correlates well with freezing responses in contextual fear conditioning, while EPM does not suggesting that the OFT may be a more useful metric of locomotor activity [73].…”

Stress inoculation modeled in mice

“…Time spent freezing was scored as the absence of all movement except respiration and is considered a measure of anxiety-like behavior in mice. 23 Time spent within 10 cm of the walls of the box was analyzed for thigmotaxis as an additional measure of anxiety-like behavior. 24 After acclimation to the open-field, object-exploration tests were conducted in the same box with a familiar white plastic cap from the home cage and a novel black plastic pipe.…”

Sex-Specific Behavioral Response to Early Adolescent Stress in the Genetically More Stress-Reactive Wistar Kyoto More Immobile, and Its Nearly Isogenic Wistar Kyoto Less Immobile Control Strain

“…The distinct definition of fear and anxiety are supported by opposing changes found after environmental challenges in these two facets of danger-induced behaviors (Heinz et al, 2021). However, human and animal studies support the opposing hypothesis showing correlations between these behaviors (Indovina et al, 2011;Ahn et al, 2013). Since anxiety measurements are based on the rodents' natural tendency to avoid open areas, it is thought to measure intrinsic anxiety-related characteristics of the animal.…”