INTEGRATING WHISKER TACTILE INPUT, BODY METRICS AND MOTIVATION IN GAP-CROSSING ACTION SELECTION

Skilled gap-crossing behavior requires integrating sensory information with knowledge of biomechanical capacities to select among distinct motor strategies. How animals integrate sensory information with an assessment of their physical abilities to guide gap-crossing behavior remains an open question. Despite the widespread use of the gap-crossing task in behavioral neuroscience, few studies have systematically examined how animals adjust their strategies when presented with gaps of increasing size, a critical approach for investigating sensorimotor decision-making. Using gap distances individually scaled to animals’ body size and quantitative behavioral analysis, we show that mice employ either forelimb-reaching or dynamic actions such as jumps or lunges to cross gaps of different widths. Strategy choice depends on a whisker-derived estimate of gap distance relative to the animals’ body dimensions and biomechanical limits. Motivational state modulates risk-taking behavior, with higher food restriction levels increasing the likelihood of jumping across gaps that exceed reaching capacity. Although mice rely on whiskers for platform edge localization, full-whisker mice retain the ability to learn or re-acquire gap-crossing performance after bilateral barrel cortex lesions. We further show that mice adopt a compensatory strategy characterized by increased reaching attempts, including at gap distances beyond biomechanical feasibility. This compensatory strategy collapses after partial sensory deprivation, revealing that intact whisker input is essential for post-lesion flexibility and sensorimotor re-learning. Our findings demonstrate that gap-crossing decisions reflect embodied computations, whereby animals evaluate moment-to-moment affordances in the context of physical constraints and internal motivational drives, providing a framework for dissecting complex sensorimotor decision-making in ethologically relevant contexts.