Object detection through dynamic motor-sensory convergence
To interact effectively with the world, animals coordinate how they move and how they sense. In natural settings, perceivers adapt their motor-sensory strategies as they approach and explore objects, dynamically shaping both the generation and interpretation of sensory cues. Previous attempts to explain this process by reducing it solely to neuronal representations have failed to capture the mechanisms underlying dynamic perception. In this study, we use precise behavioral tracking to investigate the initial phase of object interaction, asking: What motor-sensory strategies support object detection during natural approach? Using high resolution video tracking of rats freely exploring objects under infrared illumination, we analyzed how head and whisker dynamics evolved across sequential contacts. We found that whisker-object interactions converged toward a distinct line, *, within a motor-sensory plane, where small changes in voluntary whisker movements produced large changes in whisker curvature, a sensory correlate of contact force. This convergence was actively controlled, predicted head movements and marked the completion of object approach. Convergence to * was consistent across different objects, suggesting it serves as an invariant motor-sensory contingency for object detection. Proximity to *predicted the emergence of touch-induced pumps, a rapid motor-sensory reflex that further facilitated convergence within a single whisking cycle. Together, these results reveal that object detection is a closed-loop dynamic process, in which animals actively steer motor-sensory dynamics toward a robust detection-optimized state.