Brain Mechanism And Test-retest Reliability Of Behavior Measurements In Continuous Real-time Feedback Of Finger Force Paradigm

Intra-individual behavior variability as a popular study subject has been drawing a lot of attentions in recent years.Plenty of studies have found that attention-deficit / hyperactivity disorder(ADHD)patients with sustained attention deficit have elevated response time variability in performance compared to the healthy controls,and the variability has a particular periodic patterns at a model frequency around 0.05 Hz.At present,experimental paradigms for assessing the periodic patterns of intra-individual behavior variability are reaction time tasks in which switching states between trials as well as the interpolation of missing trials during data processing will affect the accuracy of the result of the response time-frequency analysis.Thus,a new paradigm,the continuous real-time feedback of finger force which continuously collects finger force as behavioral indexes to measure sustained attention was proposed to make up the limitation of the reaction time tasks.Now only a small number of researches have used continuous real-time finger force paradigm as a method to explore behavior and brain mechanism of sustained attention,so there are a number of subjects require further research in this domain.In terms of behavior study,the test-retest reliability is the very basis of all the new behavioral measurements and the psychological tests.As a new paradigm proposed for measuring sustained attention,the test-retest reliability of it is still unclear.In terms of brain imaging research,previous studies have found that the intensity of the default mode network spontaneous neuronal activity varies between continues real-time finger force feedback states and continues sham feedback states.And the functional connectives between the default mode network and other specific networks as well as with-in network connectivity also varies significantly in different feedback states.There is always an anti-correlation between the task positive network and the default mode network,suggesting that these two networks are always in a competitive relationship.And the this relationship is also related to variability in behavioral performance.Therefore,it is worthwhile to explore the variations of this competitive relationship in different states,e.g.,continues real-time finger force feedback states and continues sham feedback states.In Study 1,the test-retest reliability of behavior measurements of continues real-time finger force feedback paradigm was calculated using intraclass correlation coefficient.Present study found that the mean finger force and amplitude of low frequency fluctuation of finger force in several sub-frequency bands showed moderate to high levels of test-retest reliabilities(0.4<ICC<0.8).In Study 2,we used a seed-based functional connectivity to generate the masks of the task positive network and the default mode network in order to find out the difference of the competitive relationship between these two networks in different states.The result showed that the competitive relationship between the task-positive network and task-negative network is more sensitive to the continues real-time finger force feedback state,suggesting this competitive relationship mainly associate with external focus state.By exploring both the test-retesting reliability of behavior measurements of continues real-time finger force feedback paradigm and the brain mechanism under different finger force feedback condition,present study provides a theoretical basis for the promotion of the new paradigm in the domain of sustained attention measuring and the exploration of brain mechanism in sustained attention.