The Characteristics And Adjustment Of Low Frequency Oscillation Of Attention Network

Rhythm activity is a basic phenomenon of brain activity,and a large number of studies have shown that rhythm activity is closely related to our daily lives.Among them,low-frequency oscillation(<1 Hz)is the basic feature of the brain to complete cognitive activities.According to the scale-free nature of brain activity,the energy consumed by low-frequency oscillation is much higher than the energy consumed by high-frequency mental rhythms Therefore,elucidating the psychological and physiological mechanism of low-frequency oscillation is very important for the theoretical construction of psychology and brain science.Attention function,especially executive control function,is the hub of many other cognitive functions,which have changed throughout the life cycle and neuropsychiatric diseases.However,note that the low-frequency oscillation characteristics of the system are currently unclear.The low-frequency oscillation of attention function is a breakthrough for exploring the psychological mechanism of low-frequency oscillation,which is of vital importance for the improvement of attention theory and the significance of low-frequency oscillation.This paper adopts the attention network test paradigm,functional magnetic resonance(fMRI)and transcranial direct current stimulation(TDCS)techniques to study low-frequency oscillations.The research content is mainly composed of the following two parts:In the first part,the method of reaction time analysis,power spectrum analysis based on Welch,and Pearson correlation analysis are used to explore the relationship between the response time and low-band power in the network test.The results show that there is a significant correlation between the power of alertness,executive control and orientation and the average response time in the frequency band 0.003-0.021 Hz.In order to further test the repeatability of the frequency characteristics and provide causal evidence for the phenomenon,based on the previous results,we used TDCS intervention technology to detect the change in the low-frequency oscillation of the response after the executive control function was adjusted.It was found that when the frequency is less than 0.024 Hz,the correlation between the reaction time and the power is still very significant.This shows that there is a close relationship between the low-frequency oscillation during the attention network reaction and the task performance of each attention state.At the same time,TDCS provides causal evidence for this phenomenon,so it can be guessed that there is a connection between the low-frequency oscillation and the attention function.This finding is helpful for a preliminary understanding of the relationship between lowfrequency oscillation and attention function.In the second part,we use the whole brain signal as an entry point to further study the relationship between low-frequency oscillation and cognitive function.By calculating the degree of coupling between the response and the phase of the whole brain signal,it is found that the coupling coefficient(Modulation Index,MI)is the largest at 0-0.02 Hz,indicating that the phase of the whole brain signal and the response are the highest in this frequency band.Next,by calculating the amplitude on the phase of the whole brain signal in the response of different frequency bands,the results show that the maximum value of the amplitude of the response is mainly concentrated in the phase-30 ° to 30 °,that is,the rising phase of the sine curve.These results indicate that the phase of the whole brain signal may have an effect on the attention network response.It shows the importance of the phase of low-frequency oscillation in cognitive function.In summary,we found that the effects of attention networks mainly appear in the very low frequency range of 0.003-0.022 Hz,and provide causal evidence through TDCS.The reason for this result may be caused by the low-frequency phase of the whole brain signal,indicating that the phase of low-frequency brain activity contains cognitive information.This study reveals the frequency characteristics of attention function at different levels from behavior to the whole brain,and theoretically explains the cognitive specificity of low-frequency oscillation,which provides a new idea for the study of low frequency oscillation.