Özkan Karabacak

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A connectionist model of cortico-striato-thalamic loops unifying learning and action selection is proposed. The aim in proposing the connectionist model is to develop a simple model revealing the mechanisms behind the cognitive process of goal directed behaviour rather than merely obtaining a model of neural structures. In the proposed connec-tionist model,(More)
We introduce a test for robustness of heteroclinic cycles that appear in neural microcircuits modeled as coupled dynamical cells. Robust heteroclinic cycles (RHCs) can appear as robust attractors in Lotka-Volterra-type winnerless competition (WLC) models as well as in more general coupled and/or symmetric systems. It has been previously suggested that RHCs(More)
We analyze an example system of four coupled phase oscillators and discover a novel phenomenon that we call a " heteroclinic ratchet " ; a particular type of robust heteroclinic network on a torus where connections wind in only one direction. The coupling structure has only one symmetry, but there are a number of invariant subspaces and degenerate(More)
Based on a connectionist model of cortex-basal ganglia-thalamus loop recently proposed by authors a simple connectionist model realizing the Stroop effect is established. The connectionist model of cortex-basal ganglia-thalamus loop is a nonlinear dynamical system and the model is not only capable of revealing the action selection property of basal ganglia(More)
Motivated by the chaos suppression methods based on stabilizing an unstable periodic orbit, we study the stability of synchronized periodic orbits of coupled map systems when the period of the orbit is the same as the delay in the information transmission between coupled units. We show that the stability region of a synchronized periodic orbit is determined(More)