In questo lavoro richiamiamo alcuni esperimenti classici di psicologia della percezione dovuti a Kanizsa e a Heiss, Fields e Hess, che indicano l'importanza del concetto di direzione nei processi percettivi. Poi presentiamo un modello di corteccia, che descrive la corteccia visiva con strumenti di geometria differenziale e analisi in gruppi di Lie. È basato sulla modellazione di alcuni meccanismi neurali, ed in particolare sulla capacità delle cellule semplici di individuare in ogni punto la direzione dei bordi degli oggetti, e giustifica da un punto di vista microscopico, i fenomeni percettivi precedentemente descritti.
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Con il contributo del Ministero per i Beni e le Attività Culturali