Background:The goal of the present study was to determine whether exogenous attentional mechanisms involved in motor planning for saccades and reaches are the same for both effectors or are independent for each effect...Background:The goal of the present study was to determine whether exogenous attentional mechanisms involved in motor planning for saccades and reaches are the same for both effectors or are independent for each effector.We compared how eye and arm movement parameters,notably reaction time and amplitude,are affected by modulating exogenous attentional visual cues at different locations relative to a target.Methods:Thirteen participants(M=22.8,SD=1.5)were asked to perform a task involving exogenous attentional allocation and movement planning.The participants were asked to fixate and maintain their hand at an initial position on a screen in front of them(left or right of screen centre)and then,at the disappearance of the fixation cross,perform an eye or arm movement,or both,to a target square(mirror location of fixation cross).A distractor appeared momentarily just before the appearance of the target at one of seven equidistant locations on the horizontal meridian.Saccade reaction times(SRTs),reach reaction times(RRTs)and amplitudes were calculated.Results:Compared to the neutral condition(where no distractor was presented),distractors overall did not result in a facilitation of SRTs at any location(shorter SRTs),rather only a strong inhibition(longer SRTs)as a function of distractor target distance.In contrast,RRTs showed strong facilitation at the target location and less inhibition at further distances.However,both SRTs and RRTs followed a similar pattern in that RTs were shortest closer to the target position and were increasingly longer as a function of distractor target distance.In terms of amplitude,there was no effect of the distractor on reach endpoints,whereas,for saccades,there was an averaging effect of distractor position on saccade endpoints,but only for saccades with short SRTs.These effects were similar when either effector movement was performed alone or together.Conclusions:These findings suggest that attentional selection mechanisms have both similar and differential effects on motor planning depending on the effectors used,providing evidence for both effector independent and effector dependent attentional selection mechanisms.This study furthers understanding of the operating mechanisms of exogenous attention on eye and arm movements and the interaction between sensory and motor systems.展开更多
Background:Many studies have shown that attention is shifted toward the goal of the upcoming saccade.It has been suggested that the purpose of this attentional shift is to aid in trans-saccadic integration by acting a...Background:Many studies have shown that attention is shifted toward the goal of the upcoming saccade.It has been suggested that the purpose of this attentional shift is to aid in trans-saccadic integration by acting as a‘pointer’(Cavanagh,Hunt,Afraz&Rolfs,2010)for remembering,processing and updating objects across saccadic eye movements(Rolfs,Jonikaitis,Deubel&Cavanagh,2011).We tested this hypothesis that pre-saccadic attentional facilitation acts as a pointer for trans-saccadic integration by investigating how irrelevant post-saccadic changes influenced pre-saccadic attentional discrimination.On one hand,if pre-saccadic attentional facilitation is an independent process involved only in enhancing peripheral information before the saccade,then manipulating visual information(absence or shift)after the saccade should have no influence on discrimination.On the other hand,if pre-saccadic attentional facilitation is involved in trans-saccadic integration,changes in visual information should influence discrimination of the pre-saccadic information.Methods:We tested different conditions involving different post-saccadic changes.In the baseline condition,participants made a saccade at the appearance of an arrow and discriminated a symbol(DS)that was presented briefly before the saccade at one of six peripheral locations.The symbol was masked thereafter with a figure 8,which remained till the end of the trial.Importantly,the DS was always presented while participants were fixating at center,and only the figure 8 was present at the end of the saccade.Participants were instructed to make the saccade then report the identity of the DS(4AFC).We then tested how blanking post-saccadic information[blanking of the saccade goal(SG)location,DSOff condition;of the entire visual scene including or excluding the SG location,AllOff and DSOnly conditions]and how displacement of the figure 8s after the saccade would affect performance.Results:We observed that discrimination performance was significantly lower when the SG location disappeared during the saccade and was no longer present when the saccade was completed(DSOff,-6.9%).This decrease in performance cannot be attributed to changes in the visual scene that may have drawn attention,as this was the case for all conditions;performance was not different when the entire visual scene was blanked(AllOff,-0.0%)or when only the DS remained(DSOnly,-1.6%).We also found that the performance decreased as a function of the displacement of the figure 8 from the SG location,particularly if it was displaced outside of the saccade landing zone.Conclusions:Based on these pattern of results,we suggest that pre-saccadic attentional facilitation is indeed involved in trans-saccadic integration by acting as a location marker or pointer.The lack of a visual target at the saccade goal,even if it is irrelevant to the pre-saccadic discrimination task,disrupted performance.展开更多
文摘Background:The goal of the present study was to determine whether exogenous attentional mechanisms involved in motor planning for saccades and reaches are the same for both effectors or are independent for each effector.We compared how eye and arm movement parameters,notably reaction time and amplitude,are affected by modulating exogenous attentional visual cues at different locations relative to a target.Methods:Thirteen participants(M=22.8,SD=1.5)were asked to perform a task involving exogenous attentional allocation and movement planning.The participants were asked to fixate and maintain their hand at an initial position on a screen in front of them(left or right of screen centre)and then,at the disappearance of the fixation cross,perform an eye or arm movement,or both,to a target square(mirror location of fixation cross).A distractor appeared momentarily just before the appearance of the target at one of seven equidistant locations on the horizontal meridian.Saccade reaction times(SRTs),reach reaction times(RRTs)and amplitudes were calculated.Results:Compared to the neutral condition(where no distractor was presented),distractors overall did not result in a facilitation of SRTs at any location(shorter SRTs),rather only a strong inhibition(longer SRTs)as a function of distractor target distance.In contrast,RRTs showed strong facilitation at the target location and less inhibition at further distances.However,both SRTs and RRTs followed a similar pattern in that RTs were shortest closer to the target position and were increasingly longer as a function of distractor target distance.In terms of amplitude,there was no effect of the distractor on reach endpoints,whereas,for saccades,there was an averaging effect of distractor position on saccade endpoints,but only for saccades with short SRTs.These effects were similar when either effector movement was performed alone or together.Conclusions:These findings suggest that attentional selection mechanisms have both similar and differential effects on motor planning depending on the effectors used,providing evidence for both effector independent and effector dependent attentional selection mechanisms.This study furthers understanding of the operating mechanisms of exogenous attention on eye and arm movements and the interaction between sensory and motor systems.
文摘Background:Many studies have shown that attention is shifted toward the goal of the upcoming saccade.It has been suggested that the purpose of this attentional shift is to aid in trans-saccadic integration by acting as a‘pointer’(Cavanagh,Hunt,Afraz&Rolfs,2010)for remembering,processing and updating objects across saccadic eye movements(Rolfs,Jonikaitis,Deubel&Cavanagh,2011).We tested this hypothesis that pre-saccadic attentional facilitation acts as a pointer for trans-saccadic integration by investigating how irrelevant post-saccadic changes influenced pre-saccadic attentional discrimination.On one hand,if pre-saccadic attentional facilitation is an independent process involved only in enhancing peripheral information before the saccade,then manipulating visual information(absence or shift)after the saccade should have no influence on discrimination.On the other hand,if pre-saccadic attentional facilitation is involved in trans-saccadic integration,changes in visual information should influence discrimination of the pre-saccadic information.Methods:We tested different conditions involving different post-saccadic changes.In the baseline condition,participants made a saccade at the appearance of an arrow and discriminated a symbol(DS)that was presented briefly before the saccade at one of six peripheral locations.The symbol was masked thereafter with a figure 8,which remained till the end of the trial.Importantly,the DS was always presented while participants were fixating at center,and only the figure 8 was present at the end of the saccade.Participants were instructed to make the saccade then report the identity of the DS(4AFC).We then tested how blanking post-saccadic information[blanking of the saccade goal(SG)location,DSOff condition;of the entire visual scene including or excluding the SG location,AllOff and DSOnly conditions]and how displacement of the figure 8s after the saccade would affect performance.Results:We observed that discrimination performance was significantly lower when the SG location disappeared during the saccade and was no longer present when the saccade was completed(DSOff,-6.9%).This decrease in performance cannot be attributed to changes in the visual scene that may have drawn attention,as this was the case for all conditions;performance was not different when the entire visual scene was blanked(AllOff,-0.0%)or when only the DS remained(DSOnly,-1.6%).We also found that the performance decreased as a function of the displacement of the figure 8 from the SG location,particularly if it was displaced outside of the saccade landing zone.Conclusions:Based on these pattern of results,we suggest that pre-saccadic attentional facilitation is indeed involved in trans-saccadic integration by acting as a location marker or pointer.The lack of a visual target at the saccade goal,even if it is irrelevant to the pre-saccadic discrimination task,disrupted performance.
