  Here we study the emergence of chimera states, a recently reported phenomenon
referring to the coexistence of synchronized and unsynchronized dynamical
units, in a population of Morris-Lecar neurons which are coupled by both
electrical and chemical synapses, constituting a hybrid synaptic architecture,
as in actual brain connectivity. This scheme consists of a nonlocal network
where the nearest neighbor neurons are coupled by electrical synapses, while
the synapses from more distant neurons are of the chemical type. We demonstrate
that peculiar dynamical behaviors, including chimera state and traveling wave,
exist in such a hybrid coupled neural system, and analyze how the relative
abundance of chemical and electrical synapses affects the features of chimera
and different synchrony states (i.e. incoherent, traveling wave and coherent)
and the regions in the space of relevant parameters for their emergence.
Additionally, we show that, when the relative population of chemical synapses
increases further, a new intriguing chaotic dynamical behavior appears above
the region for chimera states. This is characterized by the coexistence of two
distinct synchronized states with different amplitude, and an unsynchronized
state, that we denote as a chaotic amplitude chimera. We also discuss about the
computational implications of such state.
