Emergence of target waves in neuronal networks due to diverse forcing currents

The electric activities of neurons could be changed when ion channel block occurs in the neurons. External forcing currents with diversity are imposed on the regular network of Hodgkin-Huxley (HH) neuron, and target waves are induced to occupy the network. The forcing current I (1) is imposed on neurons in a local region with m (0)xm (0) nodes in the network, neurons in other nodes are imposed with another forcing current I (2). Target wave could be developed to occupy the network when the gradient forcing current (I (1)-I (2)) exceeds certain threshold, and the formation of target wave is independent of the selection of boundary condition. It is also found that the developed target wave can decrease the negative effect of ion channel block and suppress the spiral wave, and thus channel noise is also considered. The potential mechanism of formation of target wave could be that the gradient forcing current (I (1)-I (2)) generates quasi-periodical signal in local area, and the propagation of quasi-periodical signal induces target-like wave due to mutual coupling among neurons in the network.