Somayeh Hafezi; Mohammadreza Doustan; Esmaeel Saemi
Abstract
. Introduction: The present study aimed to investigate the effect of anodal and cathodal brain tDCS and stimulus-response asynchrony on the backward-compatibility effect (BCE) in conditions of acute mental fatigue.Methods: The participants were 39 boys (20 to 24 years old). The instruments included ...
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. Introduction: The present study aimed to investigate the effect of anodal and cathodal brain tDCS and stimulus-response asynchrony on the backward-compatibility effect (BCE) in conditions of acute mental fatigue.Methods: The participants were 39 boys (20 to 24 years old). The instruments included the informed consent form, the Edinburgh handedness questionnaire, the dual reaction time instrument, the Stroop software, the visual analog scale to evaluate fatigue severity (VAS-F), and the tDCS device. The participants in the pre-test were tested in two conditions of non-fatigue and mental fatigue with a dual reaction time instrument. The tests consisted of two three-choice visual stimulus-response (letters and colors) with ten different stimulus onset asynchronies (SOAs). Then the subjects were randomly assigned to three Anodal, Cathodal, and Sham stimulation groups. The intervention consisted of four consecutive 20-minute sessions of tDCS stimulation on the DLPFC area. One day and four days after the last stimulation session, the tests were repeated. For inferential data analysis, Mixed Model ANOVA and One-way ANOVA tests were used at a significance level of 0.05.Results: The results showed that there is a difference between different SOAs in response time to the first stimulus (RT1) which is a representation of backward adaptation, and at lower SOAs, the RT1 is shorter. Also, there is a difference in RT1 at low SOAs between fatigued and non-fatigued conditions. However, the effect of cathodal and anodal tDCS on RT1 was very small.Conclusion: In general, the results showed that at least some central aspects related to the response can be processed in parallel. Fatigue also affects this parallel processing.
Kambiz Nouri; Seyede Nahid Shetab Booshehri; Mohammadreza Doustan
Abstract
Given the importance of preparation to respond to two stimuli in different sport conditions, the aim of this study was to investigate the effect of foreperiod and time intervals between two stimuli on psychological refractory period (PRP) in athletes. This study was semi-experimental with a within-group ...
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Given the importance of preparation to respond to two stimuli in different sport conditions, the aim of this study was to investigate the effect of foreperiod and time intervals between two stimuli on psychological refractory period (PRP) in athletes. This study was semi-experimental with a within-group design and fundamental-applied in terms of objectives. 50 male athlete students of Shahid Chamran University of Ahvaz (age range 22.47±1.45 years) were selected by convenience sampling method. A five-core processor ASUS notebook, Edinburgh Handedness Questionnaire, software and hardware to measure the psychological refractory period were used in this study. Participants responded to two visual (selective) stimuli that were presented with short time intervals as quickly as possible. Tests were conducted in dual tasks and single tasks in foreperiods of 1,2,4,8 s and time intervals of 100, 250, 500, 800 ms randomly. The data were analyzed using mean, standard deviation, within group analysis of variance at significance level (P<0.05). The results showed that the effects of foreperiod and the stimuli intervals were significant. The foreperiod of 1s and interval of 100 ms had the most psychological refractory period and foreperiod of 8s and interval of 800 ms had the lowest psychological refractory period. This study showed that the pattern of psychological refractory period was affected by experimental manipulation of the preparation processes when recognizing the stages of information processing. Contrary to the common belief that preparation time operates on premotor processes, in the present study preparation time operates on late motion processes and confirms the existence of processing bottlenecks in dual tasks
Mohammadreza Doustan; Leila Farzad; Esmaeel Saemi; Maliheh Niknam
Abstract
The aim of this study was to investigate the effect of handedness and task difficulty on effective target width and temporal accuracy of the Fitts’ speed-accuracy tradeoff task. The present study was semi-experimental and the tools used included Edinburgh handedness questionnaire, light pen, speed-accuracy ...
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The aim of this study was to investigate the effect of handedness and task difficulty on effective target width and temporal accuracy of the Fitts’ speed-accuracy tradeoff task. The present study was semi-experimental and the tools used included Edinburgh handedness questionnaire, light pen, speed-accuracy measurement device, laptop, chronometer, and metronome. The statistical population consisted of students aged between 14 and 15. The sample included 20 students who participated in this study by convenience sampling method. They were divided into two groups: left-hand and right-hand (each group 10 subjects). Each participant performed 4 trials (each trial 30 seconds) of dual target tapping task in rhythm with the metronome sound. The trials consisted of two easy and difficult tasks and each subject performed each task with dominant and not-dominant hands in rhythm with the metronome sound set up at 300 milliseconds. For statistical analysis of data, variance analysis with repeated measures was used at the significance level of 0.05. The results showed that in dominant hand, the handedness and difficulty of the task had no significant effect on the effective width of the target (P=0.973, P=0.611). Also, the handedness did not affect the average time lag (P=0.135, P=0.785), but in non-dominant hand, the average time lag was more for the difficult task than the simple task (P=0.001). In difficult tasks, participants seem to be trying to keep the spatial error rate constant by reducing the speed of the movement and to sacrifice speed for the spatial accuracy. Also, the time error (mean lag) is more influenced by the difficulty of the task than the handedness.
