The present experiments were performed in the cat in order to determine the existence of axonal branching of cortico-cortical neurones of area SI. The retrograde fluorescent double labelling technique was adopted. In a first group of animals, associative SI-SII and callosal SI-SII projecting neurones were retrogradely labelled by injecting, respectively, Fast Blue in the ipsilateral SII and Nuclear Yellow in the contralateral SII. In a second group of animals, the callosal SI-SI and SI-SII projecting neurones were retrogradely labelled by injecting, respectively, Nuclear Yellow in SI and Fast Blue in SII of the contralateral hemisphere. In each group of animals, double labelled cells were rarely found in SI. It is concluded that the different sets of cortico-cortical projections of SI arise overwhelmingly from separate populations of neurones.
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Con il contributo del Ministero per i Beni e le Attività Culturali