Common Organizational Principles of Active Sensing in Rat Mystacial Touch and Human Vision

Each mammalian species has sensory systems adapted to the demands of its ecological environment. Here, we compare two highly divergent active sensing systems: mystacial tactile sensing in nocturnal rats, which uses whisker movements to explore nearby objects, and human vision, in which eye movements redirect gaze. Although fundamentally different in their physical signals, receptors, anatomy, and sensorimotor mechanisms, both face recurring functional requirements for active sensory acquisition. We examine how these requirements are implemented across peripheral organization, sensorimotor kinematics, the physical transformation of environmental signals before receptor transduction, and sensory coding within closed sensorimotor loops. In both, spatially organized sensory arrays are maintained during active repositioning; rapid movements redirect sampling toward regions of interest, followed by finer-scale active sampling. Mechanical or optical properties of the peripheral apparatus transform environmental signals before receptor transduction, after which modality-specific neural circuits further shape sensory activity. Sensor movement structures sensory input so that multiple environmental properties can become simultaneously coded in neural activity, each potentially influencing subsequent movement components. These correspondences suggest that recurring constraints imposed by active sensing can be associated with analogous functional organization across fundamentally different sensory systems, without implying anatomical or mechanistic equivalence, convergent evolution, or a common computational algorithm.