  In this work we studied the combined action of chemical and electrical
synapses in small networks of Hindmarsh-Rose (HR) neurons on the synchronous
behaviour and on the rate of information produced (per time unit) by the
networks. We show that if the chemical synapse is excitatory, the larger the
chemical synapse strength used the smaller the electrical synapse strength
needed to achieve complete synchronisation, and for moderate synaptic strengths
one should expect to find desynchronous behaviour. Otherwise, if the chemical
synapse is inhibitory, the larger the chemical synapse strength used the larger
the electrical synapse strength needed to achieve complete synchronisation, and
for moderate synaptic strengths one should expect to find synchronous
behaviours. Finally, we show how to calculate semi-analytically an upper bound
for the rate of information produced per time unit (Kolmogorov-Sinai entropy)
in larger networks. As an application, we show that this upper bound is
linearly proportional to the number of neurons in a network whose neurons are
highly connected.
