The Neural Mechanism Of Attention Oscillation Of College Students In Visual Modality

Attention is the key to college students’ learning.Therefore,to improve college students’ learning,the mechanism of attention in space and time dimensions is an important and basic question.It is well established that attention focuses on spatial locations,enhances the corresponding behavioral and neural responses,just like a spotlight.However,for a more comprehensive understanding,the process of attention working in time dimension should be considered.Recent studies,using high temporal resolution approaches,suggest that attention is intrinsically discrete rather than continuous.Attention samples objects alternately over time or discretely samples a single source,which is the theory of ’blinking spotlight of attention’,put forward by VanRullen.Therefore,the rhythmic characteristics of behavioral performance in attention could be found,which is called attention oscillation.To improve college students’ learning ability,in this study,we improved the measuring method and investigated the neural mechanism of attention oscillation in visual modality.In study I,high temporal resolution cue-target paradigm was used in a two-alternative forced choice task(2AFC)and a four-alternative forced choice task(4AFC).A clear oscillation pattern was found,attention dynamically switched between cued and uncued location,which supported ’blinking spotlight of attention’ theory.However,this dynamic pattern could be modulated by task difficulty.Attention switched faster when the task was easy,while,it switched much more slowly when the task was difficult.This suggest’blinking spotlight of attention’is flexible.College students’attention is dynamic and flexible,modulated by task difficulty.In study II,basing on the receptive field prosperities and topography of visual areas(V1,V2,V3/VP,V4),we aimed to investigate the role of visual cortex in attention oscillation by using our improved measuring method in study I.Visual areas are sensitive to the interhemispheric divide.Thus two gratings presented across vertical meridian,cortically far from each other,while presented along the same side of vertical meridian project,cortically near from each other within the same hemisphere.Results showed that when grating were across vertical meridian,attention oscillation was vividly seen,consistent with previous studies.While gratings were in the same side of vertical meridian,attention oscillation was not clearly seen.This study indicates that attention oscillation could be modulated by cortical distance and strongly suggests that visual areas play a key role in attention oscillation.In addition to vertical meridian,gratings presented across horizontal meridian are cortically near in V1 and V4,however,cortically far in V2 and V3/VP.In study Ⅲ,we found when gratings were across horizontal meridian,attention oscillation was vividly seen,but not along the same side of horizontal meridian.This suggests V2 and V3/VP,but not V1 and V4,are the neural sites of blinking spotlight of attention.In study IV,we used a mirror stereoscope to make images in the left side project to left eye and images in the right side project to right eye.VI is the area where binocular integration begins.We investigated behavioral oscillations in visual attention under ordinary(binocular;not dichoptic)viewing condition and binocular dichoptic condition.Results showed that when gratings were presented under ordinary viewing condition,a theta rhythm was visible.While targets were presented in the same or different eye under binocular dichoptic condition,attention oscillation was clearly seen at 12.5 Hz with antiphase relationship between cued and uncued conditions.This study indicates that attention oscillation may occur at binocular visual pathway,instead of monocular visual pathway.In conclusion,the present study demonstrated that 1)attention oscillation could be clearly seen in 2AFC and 4AFC tasks.This suggest blinking spotlight is rhythmic and dynamic;2)attention oscillation pattern was modulated by task difficulty and blinking spotlight is flexible;3)V2 and V3/VP,instead of V1 and V4,play a key role in attention oscillation.In the future,basing on the whole attention network,multiple approaches and technologies should be used to investigate the neural mechanisms of attention oscillation and the theory of blinking spotlight should be improved.