We have studied the shape of a vortex core in a modified cellular automata model of the Wiener type including nonlocal space connections and a relative refractory period. We have found that a transition from circular to linear vortex core may be obtained by changing the parameters of the model. In particular, by increasing the excitability at constant refractory period the vortex core shape changes from circular at low excitability to the Wiener type linear core at high excitability. At intermediate values of excitability, cycloidal and "Z" type rotations occur. © 1990.