EN
Professor Kazimierz Jan Zielinski had his over-forty-year-long career path very closely connected with the development of the Nencki Institute. The general scope of his research was behavioral neuroscience. Much of his scientifi c work was devoted to systematic study of the defensive Pavlovian and instrumental conditioning, and to functions of the prefrontal cortex and the amygdala in aversive learning. Topics, to which Professor Zielinski had made important contributions, ranged from stimulus intensity dynamism to conditioned inhibition and processes of inhibition of delay. The director of the Nencki Institute for many terms, he also organized the Laboratory of Defensive Conditioned Refl exes within the Department of Neurophysiology. The scope of the Laboratory refl ects one of Professor Zielinski’s biggest scientifi c passions – the quest for understanding the mechanisms of avoidance learning, as well as internal complexity of this instrumental defensive response. Numerous studies at the Laboratory, many designed, performed or supervised by himself, were devoted to study parameters affecting the performance and differentiation of the avoidance response, and to examine the neuronal processes that mediate the states of fear and safety. Professor Zielinski hypothesized that different physiological mechanisms are responsible for performance of short- and long-latency avoidance responses, and that these two classes of avoidance response evoke diverse emotional states.