| It is well known that stress can adversely affect human health.The current researches on stress have focused on acute stress,that is,a transient stress state caused by laboratory intervention.In life,we are often exposed to the response of everyday stressors who ignore or mismanaged.Chronic stress can have various adverse effects on our daily work,life,and learning,resulting in changes in behavior patterns.Therefore,it is important to explore the effects of chronic stress on mental health.And previous studies on chronic stress were mostly limited to single-level attention bias.Under chronic stress,people have a negative attention bias.Based on the existing research,we have paid more attention to the function of attention control,which is the core component of cognitive function,including three aspects of attention: alerting,orienting,and executive control.Existing research also indicate that stress can damage the prefrontal cortex,a brain region involved in important cognitive abilities,such as judgment and decision making.So far,the effects of chronic stress on attentional control have focused on which components and how they affect each other.It remains to be proven.In order to solve these problems,this study uses major examinations(postgraduate entrance examinations)as sources of chronic stress.The perceived stressed scale is used as a subjective indicator for assessing chronic stress.The experimental procedure is the attention network task(ANT).The experimental techniques used are event related potential(ERP)and transcranial direct current stimulation(tDCS).Two experiments wereconducted to investigate the effects of different stress conditions on individual attention control function and tDCS intervention effect of real current stimulation on highly stressed individuals.Study 1 attempts to study the effect of chronic stress on individual executive functions from a neurological perspective.Behavioral results:Compared with the non-stress group,the response in the chronic stress group was slower and less accurate;EEG results: smaller cue-N1,cue-N2 and larger cue-P3 amplitudes were found in the chronic stress indicating they has very low efficiency and attention ability to use cues,and it is difficult to maintain alerting and accurate orienting.Compared with the non-stress group,the target-N2 amplitude is larger and the target-P3 amplitude is smaller in the chronic stress group,which indicates that the chronic stress group needs to allocate more cognitive resources to deal with conflicting target tasks,and their execution control functions decline.We speculate that excessive consumption of neuroendocrine resources in the chronic stress group may lead to changes in attention control.Study 2 combines ERP with(transcranial direct current stimulation,tDCS)technology,and explores whether tDCS stimulation of the prefrontal lobe in the chronic stress group can alleviate stress and affect brain amplitude.We performed tDCS stimulation in chronically stressed individuals for five consecutive days.It was found that the subjects who received the real stimulus responded faster than the subjects who receiced false stimulus.And tDCS real stimulation can regulate the frontal lobe area and produce smaller target-N2 amplitude to improve the executive function of chronic stressors.The main innovations of this study are:(1)previous studies have mostly explored acute stress.This study cuts from chronic stressors in real life,and expands from the study of attention bias to a comprehensive study of attention control;(2)Exploring tDCS intervention,extending from behavioral level to neural level,using the design of brain area indicators to investigate the effect ofintervention;(3)Extending from immediate intervention to continuous short-term intervention,Follow-up questionnaires,behavioral responses,and brain area indicators were used to comprehensively examine subject differences and intervention effects.This has important theoretical significance and practical value for finding clinical intervention methods for chronic stress.Combined with the above two studies,the following conclusions can be drawn:(1)Chronic stress will lead to the decline of individual attention,alertness,orientation and executive function.(2)High-stress individuals have less ability to pay attention to effective information,and use clues less efficiently,and need to allocate more cognitive resources to handle conflicting target tasks.(3)After receiving tDCS real current stimulation,the high-stress group felt less stress and shorter behavioral response time,and there was no significant difference in the stress level of the false-stimulation group.(4)After receiving the tDCS real current stimulation,the high-stress group produced smaller target-N2 amplitude,indicating that it consumed less cognitive resources to complete the task,and their execution control function was enhanced. |
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