Small assemblies of Fitzhugh-Nagumo neural oscillators are used to study a type of threshold coupling coming from biology where it is used to model synapses. Phase locking and coincidence detection is modelled in the two most simple coupling configurations. For the threshold coupling Fast Threshold Modulation is used. The mechanism of phase locking for master slave coupling is revealed. A setup for coincidence detection is presented for which also the influence of noise is studied and it is shown that the presence of noise can increase the sensitivity of the detection, a phenomenon that is known is Stochastic Resonance.