| Working memory is a memory system with limited capacity to process and store information temporarily.Acute stress refers to the nonspecific response of an organism when unexpected and uncontrollable environmental demands exceed the organism's natural regulatory capacity.It has been found that acute stress can impair the activity of theta waves in working memory processing,and this frequency band is mainly responsible for the organization of information in working memory and inhibits irrelevant information.At the same time,working memory capacity will affect the ability of subjects to filter out distracting information.This effect is manifested in the amplitude of CDA in ERP.CDA is in the maintenance stage of visual memory project,the contralateral brain area of the target field will show more negative waves than the ipsilateral brain area,which is an ERP index that can reflect the visual working memory retention.But what needs to be further investigated is whether acute stress affects the filtering of distracted information in working memory or the storage of target information,or both,and how does acute stress affect information encoded differently in working memory?Based on this,this study took healthy adult male college students as subjects and used event-related potential technology to explore the effects of acute stress on filtering distracted information and storing target information in working memory,as well as the effects of acute stress on information encoded in different ways in working memory through two studies.In the first experiment,72 subjects were recruited and divided into the control group(36 people)and the stress group(36 people)on the basis of ensuring homogeneity of the two groups through the pre-experiment--change detection task and trait anxiety scale score.The formal experiment adopted a mixed experimental design of 2(group: stress group,control group)×3(memory type: two reds,four reds,two reds and two blues(distraction information condition)).Maastricht Acute Stress Test(MAST)was used to induce the Stress state of the subjects,and the change detection task paradigm was used to measure the filtering of distracted information and the storage of target information.MAST normal form was used to induce the stress state of the subjects in the stress group,and the control group followed the same procedures as the stress group,except that they changed the ice water into warm water,and the oral calculation was relatively simple.Firstly,after arriving at the laboratory,the subjects took a five-minute rest,then filled in the State Anxiety Scale,Positive and Negative Emotion Scale and collected the first saliva.Then go to shampoo,do change detection exercises after shampoo,fill in the second questionnaire after practice and collect the second saliva.Then prepare for ERP experiment and stress induced experiment,fill in the third questionnaire and collect the third saliva.After collecting saliva,change detection tasks were carried out.At the second rest(about 15 minutes after stress),the subjects filled in the fourth questionnaire and collected the fourth saliva.At the end of the task,fill in the fifth questionnaire and collect the fifth saliva.In the task,the subjects remembered the direction of the red rectangle on the side of the arrow according to the prompt.After a period of delay,they judged whether the detection arrays had changed compared with the memory arrays.Memory arrays consist of three situations: two red,four red,two red and two blue(distraction information condition).EEG was recorded simultaneously during the unilateral change detection task.For the collected salivary cortisol,the collected positive and negative emotion scale,state anxiety scale,and the response time,correct rate,memory capacity,and CDA amplitude of the subjects were analyzed.The experimental results showed that:(1)The salivary cortisol concentration,the positive and negative emotion scale scores and the state anxiety scale scores were compared between the two groups,and the stress induction of the stress group was found to be successful.Specifically,the salivary cortisol content of the control group was significantly lower than that of the stress group after stress induction;the negative emotion scale and the state anxiety scale of the stress group were higher than the control group;the positive emotion scale There was no difference in scores,but the scores were getting lower and lower;indicating that the MAST paradigm succeeded in inducing the stress state of the subjects.(2)In the change detection task,the response time of the stress group was longer than that of the control group,and there was no difference in the correct rate.(3)The CDA of the stress group and the control group showed significant differences in memory two reds and four reds,while there was no difference in memory two reds and two blues.In the second experiment,57 subjects were recruited into the control group(29 persons)and the stress group(28 persons)according to the method of Experiment 1.The formal experiment used a mixed experimental design of 2(group: stress group,control group)× 4(memory type: two red at the same time,presenting four reds,delaying two reds and delaying two blues).The MAST paradigm was used to induce the stress state of the subject,and the change detection task paradigm measures the influence of the individual on the information of different coding modes,and records the EEG.During the experiment,saliva cortisol was collected,and the state anxiety scale and the positive and negative emotion scale were collected five times.The experimental procedure was consistent with the experimental one.For the collected salivary cortisol,the positive and negative emotion scales collected,the state anxiety scale,and the response of the subjects,the correct rate,memory capacity,and amplitude of CDA were analyzed.The experimental results showed that:(1)The salivary cortisol concentration,the positive and negative emotion scale scores and the state anxiety scale scores were compared between the two groups,and the stress induction of the stress group was found to be successful.Specifically,the salivary cortisol content of the control group was significantly lower than that of the stress group after stress induction;the score of the state anxiety scale was higher than that of the control group;the positive emotion scale scores were different after stress,and the control group.The score was higher than that of the stress group,but the score was getting lower and lower;the negative emotion scale of the stress group had no significant difference between the two groups,but the score of the stress group was higher than that of the control group.It indicates that the MAST paradigm succeeded in inducing the stress state of the subject.(2)In the change detection task,the response of the stress group was longer than that of the control group,and there was no difference in the correct rate.(3)There is no difference between the two groups in terms of memory capacity.(4)On CDA,there were significant differences between control group and stress group in memory of two red and two blue,but no significant differences in delayed two red and delayed two blue.Based on the above two experiments,the following conclusions are drawn:(1)The MAST paradigm can significantly induce the stress state of the subject both physically and psychologically.(2)Acute stress can affect the storage of target information,but it will not affect the filtering of distraction information.Even those in the high working memory group will still damage the storage of the target information after stress,but not Will affect the filtering of distraction information.(3)Subjects do not impair their ability to add new items after stress. |
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