Temporal patterns of synchrony in a pyramidal-interneuron gamma (PING) network

TL;DR

This study investigates how synaptic strength influences the timing and pattern of gamma oscillation synchronization in a neural network, revealing that temporal patterns can change independently of overall synchronization strength, which may impact neural assembly formation.

Contribution

It demonstrates that synaptic and membrane kinetics modifications can alter the temporal patterning of gamma synchronization independently of average synchronization levels.

Findings

Changes in synaptic strength affect the timing of synchronization intervals.

Temporal patterning varies independently of average synchronization strength.

Short desynchronizations are common, facilitating neural assembly dynamics.

Abstract

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.