Related Experiment Video
Updated: Jan 29, 2026

Mimicking a Space Mission to Mars Using Hindlimb Unloading and Partial Weight Bearing in Rats
Published on: April 4, 2019
Behavioral and Neurobiological Correlates of Resilience in the Hindlimb Unloading Mouse Model: A Longitudinal
Arianna Racca1, Patrizia Pignataro2, Roberta Zerlotin2
1Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, 00161 Rome, Italy.
Abstract:
Among ground-based paradigms used to reproduce altered gravity exposure, the hindlimb unloading (HU) model is widely employed to simulate microgravity conditions by removing gravitational loading from the hindlimbs. Despite its extensive use, behavioral adjustments during suspension remain poorly characterized, although they may provide valuable indicators of animal welfare and individual susceptibility. Here, we comprehensively characterized the behavioral profile of mice during and after HU using a dedicated ethogram, with the aim of identifying behavioral markers associated with individual coping strategies. Several exploratory and postural behaviors showed marked time-dependent modulation, with baseline exploratory activity predicting a more adaptive behavioral trajectory during suspension, possibly indicative of greater resilience. In parallel, brain levels of the neurotrophins NGF and BDNF were measured to explore their relationship with behavioral outcomes. Although no significant group differences were detected, suspended mice displayed a progressive reduction in both neurotrophins over time, which paralleled behavioral adaptation. Together, these findings indicate that specific exploratory behaviors represent reliable predictors of resilience to HU, while NGF and BDNF may reflect ongoing neuroplastic processes associated with prolonged suspension.
Related Concept Videos
Longitudinal Research
Correlations
Correlation and Causation
Correlation versus Causation
If the dependent variable increases or decreases when the independent variable increases, there is a positive or negative...
Correlation
Two variables, for example, a and b, are said to be positively correlated if both variables move in the same direction. In other words, a positive correlation exists between two variables, a and b, if:
Longitudinal Studies
What is Behavior?

