Visual-looming Shadow Task with in-vivo Calcium Activity Monitoring to Assess Defensive Behaviors in Mice

Abstract

There has been a clear movement in recent years towards the adoption of more naturalistic experimental regimes for the study of behavior and its underlying neural architecture. Here we provide a protocol that allows experimenters working with mice, to mimic a looming and advancing predatory threat from the sky. This approach is easy to implement and can be combined with sophisticated neural recordings that allow access to real-time activity during behavior. This approach offers another option in a battery of tests that allow for a more comprehensive understanding of defensive behaviors.

Single-Cell Transcriptional Changes in Hypothalamic Corticotropin-Releasing Factor–Expressing Neurons After Early-Life Adversity Inform Enduring Alterations in Vulnerabilities to Stress

“…The functional role of PVN CRF cells in orchestrating behavioral responses to stress has not been fully elucidated. A requirement of these neurons in behavioral responses to threat was recently shown ( 8 ), and so we tested ELA and control mice in a test eliciting threat responses, the looming shadow task ( 66 ). Escape behaviors of ELA mice were significantly higher than control mice ( t 22 = 2.449, p = .02) ( Figure 5C , D ), suggesting that ELA-induced transcriptional changes may contribute to altered adult behavioral responses to stressful threats.…”

“…The looming shadow task is associated with PVN CRF neuronal activity ( 8 ). The entire task was performed in the dark active phase as described previously ( 66 ) and in the Supplement . Response to the looming stimulus was scored as absent, freezing, or escape behavior and recorded both live and on video (control: n = 15 mice from 4 litters; ELA: n = 15 mice from 5 litters).…”

Single-Cell transcriptional changes in hypothalamic CRH-expressing neurons after early-life adversity inform enduring alterations in responses to stress

“…The looming shadow task is largely dependent on the CRH neurons of the paraventricular nucleus (PVN) of the hypothalamus (Daviu et al 2020b). The task was performed as described previously (Daviu et al 2020a). Briefly, animals were initially habituated to an arena containing a shelter for 15 minutes during their dark cycle.…”

“…A requirement of these neurons d in behavioral responses to threat such as fleeing or freezing was recently shown (Daviu et al 2020b). Therefore, tested the consequences of ELA on behaviors mediated by PVN-CRH cells by employing a test for eliciting threat responses, the looming shadow task (Daviu et al 2020a). In this test, escape behaviors of male mice raised under ELA conditions were significantly higher compared to controls (t(22)=2.449, p=0.02) (Figure 5C-D).…”