  Synchronization in neural system plays an important role in many brain
functions. Synchronization in the gamma frequency band (30Hz-100Hz) is involved
in a variety of cognitive phenomena; abnormalities of the gamma synchronization
are found in schizophrenia and autism spectrum disorder. Frequently, the
strength of synchronization is not very high and is intermittent even on short
time scales (a few cycles of oscillations). That is, the network exhibits
intervals of synchronization followed by intervals of desynchronization. Neural
circuits dynamics may show different distributions of desynchronization
durations even if the synchronization strength is fixed. In this study, we use
a conductance-based neural network exhibiting pyramidal-interneuron (PING)
gamma rhythm to study the temporal patterning of synchronized neural
oscillations. We found that changes in the synaptic strength (as well as
changes in the membrane kinetics) can alter the temporal patterning of
synchrony. Moreover, we found that the changes in the temporal pattern of
synchrony may be independent of the changes in the average synchrony strength.
Even though the temporal patterning may vary, there is a tendency for dynamics
with short (although potentially numerous) desynchronizations, similar to what
was observed in experimental studies of neural activity synchronization in the
brain. Recent studies suggested that the short desynchronizations dynamics may
facilitate the formation and the break-up of transient neural assemblies. Thus,
the results of this study suggest that changes of synaptic strength may alter
the temporal patterning of the gamma synchronization as to make the neural
networks more efficient in the formation of neural assemblies and the
facilitation of cognitive phenomena.
