Research On Frequency Specificity Of Salience Network Based On Resting State Functional Magnetic Resonance Imaging

The basic characteristic of neural activity is the rhythmicity of neural activity,which refers to the activity characteristics of neurons at a certain frequency.The neuronal oscillations in different brain regions have different distinctive natural frequencies,the higher function level the brain area is,the lower distinctive natural frequency is,which is represented as the low frequency neural oscillations that tend to functional integration.The functional segregation of local information processing appears in the higher level of brain activity.However,due to the deficiency of technology,the mechanisms of low frequency neural oscillations are unable to reveal,and more advanced technologies are needed.Functional magnetic resonance imaging(fMRI)is the main tool for the research of low frequency neural oscillations.The main reasons are that the low frequency signal of fMRI is stable,the spatial resolution of the image is high,and the existence of neural activity is correlated.In the traditional low-frequency oscillation research,the salience network(SN)can be divided into dorsal cognitive network and ventral emotional network.The main region of the network is insula,the right anterior insula(rAI)plays an essential role in generating adaptive behavior through coordinating different brain networks.A pivotal question needs to be replied is whether the internetwork modulation is spatiotemporally constrained.In other words,whether the different sub regions of rAI have functional integration or segregation,whether exists spectral fingerprint in different frequency bands.The narrow frequency interval is unable to elaborate complicated functional role of those networks.Using the Human Connectome Project dataset,we compared the functional connection patterns(FCPs)of dorsal and ventral rAI in the traditional infraslow frequency band(0.001~0.1Hz),the slow frequency band(0.1~0.694Hz)and full frequency range(0.001~0.694Hz).We can find the connections between the dorsal rAI and externally-oriented networks and between the ventral rAI and internally-oriented networks,such as the connections between dorsal salience network and central executive network,whereas the connections between ventral salience network and default mode network,even exist different frequency effect regions in these two salience networks.The asymmetry and concentration are important characteristics of FCPs of the two SNs in the slow frequency range,and there are partly overlapped FCPs of the two SNs.Frequency-specific psychological correlations of two systems also exist.These findings provide valuable insight into understanding frequency specificity of FCPs and reveal the frequency-specific psychological mechanisms of brain networks,which can range from low frequency analysis to higher frequency band,such as the inhibitive role of occipital alpha wave.These findings have important implications for functional integration and functional segregation and internetwork coordination.