Emergence of ultrafast sparsely synchronized rhythms and their responses to external stimuli in an inhomogeneous small-world complex neuronal network. (September 2017)

• Record Type: Journal Article
• Authors: Kim, Sang-Yoon; Lim, Woochang
• Is Part Of: Neural networks. Volume 93(2017)
• Page Start: 57
• Page End: 75
• Publication Date: 2017-09
• Subjects: SR and LR interneurons -- Inhomogeneous small-world network -- Inhomogeneous betweenness centrality -- Ultrafast sparsely synchronized rhythms -- Synchronization suppression and enhancement; Neural computers -- Periodicals; Neural networks (Computer science) -- Periodicals; Neural networks (Neurobiology) -- Periodicals; Nervous System -- Periodicals; Ordinateurs neuronaux -- Périodiques; Réseaux neuronaux (Informatique) -- Périodiques; Réseaux neuronaux (Neurobiologie) -- Périodiques; Neural computers; Neural networks (Computer science); Neural networks (Neurobiology); Periodicals; 006.32
• DOI: 10.1016/j.neunet.2017.04.002
• Languages: English
• ISSNs: 0893-6080

Abstract

Abstract: We consider an inhomogeneous small-world network (SWN) composed of inhibitory short-range (SR) and long-range (LR) interneurons, and investigate the effect of network architecture on emergence of synchronized brain rhythms by varying the fraction of LR interneurons p l o n g . The betweenness centralities of the LR and SR interneurons (characterizing the potentiality in controlling communication between other interneurons) are distinctly different. Hence, in view of the betweenness, SWNs we consider are inhomogeneous, unlike the "canonical" Watts–Strogatz SWN with nearly the same betweenness centralities. For small p l o n g, the load of communication traffic is much concentrated on a few LR interneurons. However, as p l o n g is increased, the number of LR connections (coming from LR interneurons) increases, and then the load of communication traffic is less concentrated on LR interneurons, which leads to better efficiency of global communication between interneurons. Sparsely synchronized rhythms are thus found to emerge when passing a small critical value p l o n g ( c ) ( ≃ 0.16 ) . The population frequency of the sparsely synchronized rhythm is ultrafast (higher than 100 Hz), while the mean firing rate of individual interneurons is much lower (∼30 Hz) due to stochastic and intermittent neural discharges. These dynamical behaviors in the inhomogeneous SWN are also compared with those in the homogeneous Watts–Strogatz SWN, in connection with their network topologies. Particularly, we note that the main difference between the two types of SWNs lies in the distribution of betweenness centralities. Unlike the case of the Watts–Strogatz SWN, dynamical responses to external stimuli vary depending on the type of stimulated interneurons in the inhomogeneous SWN. We consider two cases of external time-periodic stimuli applied to sub-populations of the LR and SR interneurons, respectively. Dynamical responses (such as synchronization suppression and enhancement) to these two cases of stimuli are studied and discussed in relation to the betweenness centralities of stimulated interneurons, representing the effectiveness for transfer of stimulation effect in the whole network. Highlights: An inhomogeneous small-work neuronal network, composed of long-range (LR) and short-range (SR) interneurons, is considered. Distribution of betweenness centralities, representing the effectiveness for transfer of stimulation effect, is inhomogeneous. Betweenness centralities of LR interneurons are much larger than those of SR interneurons. Effects of network architecture on emergence of sparsely synchronized rhythms are studied. Dynamical responses to external time-periodic stimuli are investigated in connection with betweenness centralities of stimulated interneurons.