利用跨顱磁刺激探討主動式注意力攫取的神經機制;Probe the neural mechanisms of contingent attentional capture with transcranial magnetic stimulation

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Title:	利用跨顱磁刺激探討主動式注意力攫取的神經機制;Probe the neural mechanisms of contingent attentional capture with transcranial magnetic stimulation
Authors:	張期富;Chi-Fu Chang
Contributors:	認知與神經科學研究所
Keywords:	注意力攫取;注意力控制;跨顱磁刺激;TPJ;attentional capture;FEF;attentional control;TMS
Date:	2008-07-04
Issue Date:	2009-09-22 11:02:13 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	任何事物吸引人們注意力的過程，皆反映了自主性控制與刺激驅動這兩種注意力控制的互動。在探討何種刺激能夠引吸到注意力的優先處理時，主動式注意力攫取說明符合注意力設定的刺激更容易影響注意力處理。本研究利用不同顏色突現刺激建立主動式注意力攫取的現象，發現當突現刺激與目標同色時，其干擾效果最強。即使在使用中央線索提受試者目標位置，同色的突現刺激仍造成顯著的影響。藉由此作業，本研究欲利用跨顱磁刺激探討背後的神經機制。根據理論模型指出，注意力控制可被劃分為兩個網路。背側側網路主要負責自主性控制，產生注意力設定。而腹側網路則是側化在右邊，負責偵測在自主性控制之外的相關刺激，當相關刺激出現時得以中斷背側網路正在執行的作業，讓注意力能重新導向或分佈至該刺激上。主動式注意力攫取與以上兩者皆有所關聯，本研究各自選擇右側的FEF與TPJ代表背側與腹側系統中的一員，利用跨顱磁刺激探討其中的因果關系。在跨顱磁刺激實驗一、二發現，不論刺激區域為何，在目標出現前施予磁刺激會減少反應時間；而在目標出現之後於FEF施予磁刺激，則延長反應時間，但前述的磁刺激效果皆與主動式注意力攫取無關，磁刺激對任何突現刺激的影響方式皆相同。根據可能的設計問題，跨顱磁刺激實驗三採用與之前實驗不同的設計，控制注意力可能的移動方向，並納入相容性效應確定突現物是否引發注意力移動。結果發現，在目標出現前刺激FEF與TPJ將降低不相容刺激所造成的干擾，但此一磁刺激效果依舊與主動式注意力攫取無關，磁刺激對於不同突現刺激的影響方式仍然相同。雖然本實驗觀察到FEF與TPJ與注意力處理之間有所關聯，但並無法了解主動式注意力攫取背後可能的神經機制。此結果可能是由於實驗設計上細格內嘗試次不足所致，因許多可能的重要效果其統計顯著不足，此點是未來研究需補足之處。The interaction between voluntary attentional control and stimulus-driven attentional control may result in the efficiency of the deployment of attention.. Nontarget items that are salient and match for the defining feature of the target can capture attention effectively. This phenomenon is so-called contingent attentional capture because the capture is contingent on that the features of the nontarget need to be consistent with the attentional set of the task. In the present study, we used contingent attentional capture task and repetitive transcranial magnetic stimulation (rTMS) to investigate the neural mechanism of attentional control. Previous studies showed that two neural networks are involved in two attentional control systems. The dorsal frontoparietal network generates and maintains voluntary control; the ventral frontoparietal network is modulated by attentional shifts to behaviorally relevant stimuli. We choose right frontal eye fields (rFEF) and right temporoparietal junction (rTPJ) as the representative sites of dorsal and ventral networks, respectively. In the first two TMS experiments, rTMS (10Hz, 200 ms) was applied over rFEF either 200 ms before, simultaneously with, or 200 ms after the onset of the visual search array. When rFEF and rTPJ were stimulated before the onset of search array, the overall reaction time was decreased. However, when rFEF were stimulated 200ms after the onset of the stimuli, the reaction time was increased. The results suggested that rFEF may play a causal role in deployment of attention. However, the two experiments did not observe selective modulation of TMS on contingent attentional capture. In the third set of TMS experiments, we applied some modifications to test the attentional shift caused by contingent capture and the results of compatibility effects for the verification that abrupt onset caused attentional shifting into the stage of motor preparation. The results also shown rTMS applied on the both regions would reduce the reaction time cost of incompatible onset regardless of any onset types. The present results demonstrate the causal relationship between rFEF and visual attention, however, several experiments derived from the current study are needed to be carried out for elucidating the functional roles of rTPJ and rFEF in the control of the contingent attentional capture.
Appears in Collections:	[College of Science Institute of Cognitive Neuroscience] Electronic Thesis & Dissertation

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