Dissociation of vertical and horizontal components of somesthetic orientation-localization during recovery from cortical damage: Implication regarding central associative functions

Blindfolded cats in which SII and adjacent areas had been ablated were tested for their ability to locate cutaneous stimuli as demonstrated by their bringing the mouth into contact with the stimulated point. During recovery, seven cats went through a phase in which they displayed dissociations of the vertical and horizontal components of the orientation-localization movement: either they moved the head downward before initiating any lateral movement or they turned towards the side of stimulation well before achieving accurate proximodistal localization. Hypotheses are offered about which aspects of anatomy and physiology are involved in proximodistal and lateral localization, and a simple mathematical model is given to suggest that one reason why such central associative functions in movement may have evolved is because they require fewer neurons than an alternative conceivable design.