| In recent years,many scholars have found that attention and ongoing alpha activty have close relations,alpha band(8 to 12 hz)neural activity oscillation amplitude increases usually damage visual processing,such as when a region of visual attention is increased,the area that corresponds to the alpha wave power will reduce,but when no longer need to pay attention to these regions,and enhance the alpha wave power.The relationshipbetween visual time structure processing and alpha wave is also very close.Studies show that two events are more likely to be perceived as simultaneous events when they occur continuously and rapidly in the same period.But when two events do not occur in the same period,they fall into different segments and are perceived as continuous events.Temporal processing of attention and vision seems to be linked by alpha waves,but limited research does not provide sufficient evidence for a link.The main purpose of this study was to explore whether temporal attention can modulate the integration capability in time structure processing and if so,the relationshipbetween such modulation and background neural oscillations in the alpha band.The experiment recruited 21 college students,Experiments using Missing point task paradigm(Missing element task)measuring time integration ability,in the formal experiments were based on prior knowledge is needed time information forecast the timing of the target stimulus appeared and judging as accurately as possible,time information for clues tips and target stimulus intervals,time information changes between chunking.The experimental conditions included neutral conditions(randomly selected at intervals of 500-1000ms),short delay conditions(500ms)and long delay conditions(1000ms).Due to the huge individual differences in time integration ability,the perceptual threshold of time integration ability was measured by psychophysical method before the formal experiment,so as to control the difficulty of tasks in the formal experiment and keepthe difficulty of tasks in the formal experiment relatively consistent.The accuracy and eeg signals of the subjects were recorded and analyzed in the formal experiment.For eeg signals,event-related potentials and alpha wave phase and power based on time-frequency analysis were calculated,respectively.The results of this study show that the demerit recording of behavioral performance shows that time attention can enhance the ability of time structure processing,but this effect is limited to the condition of short delay.ERPresults showed that temporal attention modulated the components of N1 and P300 and the CNV before stimulation,but these effects only appeared in the case of long delay.EEG time-frequency analysis shows that time attention modulates alpha wave power,but the effect of time attention is not uniform under different cue lengths: effective cues cause alpha wave power to decline more rapidly in short delays,and vice versa in long delays.The reasons for this result may include the asymmetry of time attention effect and the inaccuracy of time perception.In addition,no modulation of alpha wave phase was found in the experiment.In this study,ITPC(inter-trial phase coherence)was used as an indicator of phase consistency before stimulation,and the calculation results showed that there was no significant difference in phase consistency between correct and wrong responses under neutral conditions,and no significant difference was found between different cue duration conditions.This result demonstrates the ability of temporal attention to modulate the processing of time structures,but this effect is limited to cases where the time interval between the cue cue and the target stimulus is relatively short.The results of this study show that time attention can modulate the power of alpha wave as well as space attention,but time attention does not modulate the phase of alpha wave. |
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