Een bedradingdiagram op single-neuronresolutie onthult functioneel specifieke morfologische kenmerken die ten grondslag liggen aan de verwerking van proprioceptieve informatie.

Proprioceptive afferents provide essential sensory feedback for motor control, yet principles of their muscle-specific central organization remain unresolved. This thesis integrates viral-mediated sparse labeling, whole-organ tissue clearing, and single-neuron reconstruction to generate three-dimensional maps of forelimb distal and proximal flexor and extensor's proprioceptive afferents from biceps brachii, triceps brachii, flexor digitorum superficialis, and extensor digitorum communis across the caudal medulla and cervical spinal cord at single-cell resolution. Global morphological analyses revealed limited segregation of muscle identity at the whole-neuron level. To uncover localized specializations, an attention-based multiple instance learning framework with anatomical and collateral binning enabled spatially resolved detection of discriminative features linked to muscle type. The model assigned highest attention to the caudal medulla and C5-C7 brachial enlargement, where feature loadings highlighted segment-specific peaks in endpoint density, axon length, and spatial coverage paralleling motor neuron pool distributions, including the distinctive bimodal pattern of extensor digitorum communis. Collateral attention maps localized the most informative collaterals to domains overlapping homonymous motor neuron columns, revealing possible sensory-motor topography. Spatial mapping of terminals further demonstrated dorsal-ventral and medial-lateral segregation of proprioceptive endpoints in medulla and spinal cord, with flexor-extensor and distal-proximal segregation reflecting functional antagonism and dexterity demands. These findings show that muscle identity is not represented by global arbor morphology but by region-specific morphological signatures concentrated at processing hubs and motor control segments. This framework highlights how proprioceptive afferents establish muscle-specific sensory representations and potential sensory-motor coupling.