Bericht der Senckenbergischen Naturforschenden Gesellschaft in Frankfurt am Main (1897-1921.) (20357868962)

Three sequential sketches show a cross-section of the human head in profile, illustrating how the eyes connect to the brain. The drawings map the path of the optic nerves into the hollow cavities or ventricles of the brain, which were thought to process sensory information. The rightmost figure provides a naturalistic profile of a face, while the sketches to the left become more diagrammatic, focusing on internal anatomy.

This study reflects the Renaissance attempt to find a physical location for the 'sensus communis' (common sense), a concept from Aristotelian natural philosophy. Leonardo sought to identify the specific part of the brain where the soul processed sensory input and generated thought.