  We propose a discrete time dynamical system (a map) as phenomenological model
of excitable and spiking-bursting neurons. The model is a discontinuous
two-dimensional map. We find condition under which this map has an invariant
region on the phase plane, containing chaotic attractor. This attractor creates
chaotic spiking-bursting oscillations of the model. We also show various
regimes of other neural activities (subthreshold oscillations, phasic spiking
etc.) derived from the proposed model.
