Santiago Ramon y Cajal and Ivan Petrovich Pavlov: does complementarity exist between their theories?

Introduction. Few authors have compared the life and work of Cajal and Pavlov and they refer normally to their coincidence at the XIV Medicine International Congress of Madrid in 1903. Aims. To describe the theoretical models of both authors and to explain the possible complementarities between the works of Cajal and Pavlov. Development. We describe the principal bases of the 'neuron theory' of Cajal, compared to the 'reticulated theory', the principal results of Cajal's investigations and the contributions he made to the concept of plasticity. We describe the 'Pavlov's conditional reflections theory', its principal postulates, pavlovians laws and the typology of the nervous system according to Pavlov. Conclusions. The works of Cajal and Pavlov can be understood as complementary under Wallon's proposal and in the frame of the 'strategic epistemology', where the advance of the science is achieved from different but complementary strategies that help each other to construct stronger theoretical models.