注意力對重複效果影響之事件相關電位研究

An Event-Related Potential Study on the Attentional Modulation of Repetition Effect

李思賢(Lee Szu-Hsien)

指導教授 ： 許禕芳

國立臺灣師範大學/教育學院/教育心理與輔導學系/碩士(2023年)

https://doi.org/10.6345/NTNU202300266

摘要

當刺激重複出現時，會使神經活動減少，即重複抑制。這種現象最初被認為是由下而上的感覺訊息處理所引起，知覺的預期編碼模式則假設了重複效果反應由上而下產生的預期誤差的衰減。先前的事件相關電位研究顯示，這個衰減現象依序包含注意力獨立和注意力依賴的歷程，當出現單次重複刺激時，無論注意力的狀態如何，預期誤差的衰減都會出現在較早的事件相關電位成分上，但在較晚的事件相關電位成分上，只有在有注意時預期誤差的衰減會出現，不注意時的預期誤差衰減並不會出現。先前的研究通常基於重複一次刺激來研究這個問題。但當重複次數增加時，重複抑制和注意力之間的關係會如何隨時間演變，目前所知並不多。本研究欲使用腦電波技術瞭解在超過一次的重複刺激中，所引起注意力獨立和注意力依賴的效果之事件相關電位效果會如何變化。研究設計為每一個實驗區塊，有一組重複音流和填充音流，兩種音流交錯呈現。重複音流包含多組序列的聲音，每一序列為4個重複音調組成。填充音流則是不會馬上重複的隨機音調。為了能更好的呈現聽覺環境中隨時變化的特性，重複音流包含了連續和間歇兩種類型。受試者會被要求專注於重複音流或填充音流，以利分別測量在重複音流中注意和不注意的重複效果。本研究發現在N1的注意力依賴重複效果顯示快速下降，表示預測誤差的自動衰減的快速可塑性。然而，在連續重複音流中，注意和不注意兩種情況下，N1沒有呈現完全一致的重複抑制型態，但目前尚不清楚背後的原因。此結果僅在連續音流中發現，但沒有在間歇音流中發現，表示暫時性的干擾存在與否，會影響預期誤差衰減的容易度。而在本研究中，並沒有在P2發現注意力依賴的重複效果，這表示P2的注意力依賴重複效果可能是不穩定的現象。

關鍵字

重複抑制 ； 預期誤差 ； 注意力 ； 事件相關電位

並列摘要

Repetition suppression refers to a reduction in neural responses to stimulus repetition. This phenomenon was initially believed to result from the bottom-up processing of perceptual information. This view was later challenged by the predictive coding model of perception which postulates that repetition suppression reflects the top-down attenuation of prediction errors. Recent event-related potential (ERP) studies further suggested that repetition effect comprises of sequentially ordered attention-independent and attention-dependent processes. Specifically, repetition effect appears on earlier ERP components regardless of attention. On the other hand, repetition effect only occurs in attended but not unattended condition on later ERP components. However, previous research commonly examined repetition effect using one-time repetition of the stimuli. Less is known concerning how the relationship between repetition effect and attention evolves over time when the number of repetitions increases. This electroencephalography (EEG) study aimed at investigating how attention-independent and attention-dependent repetition effects on ERPs might evolve beyond one-time repetition of the stimuli. Participants were presented with blocks of tones where a roving stream (consisting of trains of 4 repeated tones) was interleaved with a filler stream (consisting of random tones without immediate repetitions). To better represent the everchanging nature of our auditory environment, the roving stream could be either continuous or intermittent. Participants were required to focus on either the roving stream or the filler stream to allow the measurement of attended and unattended repetition effects in the roving stream. The attention-dependent repetition effect on the N1 showed a fast depression and then rebounded, demonstrating the rapid plasticity of auditory processing. However, it is unclear why the exact pattern of repetition effect differed between attended and unattended conditions. Moreover, this pattern was found in the continuous-roving but not intermittent-roving stream, indicating that the absence or presence of temporary disruptions could affect the ease to attenuate prediction errors. On the other hand, no attention-dependent repetition effect was found on the P2, suggesting that the attention-dependent repetition effect here might be volatile.

並列關鍵字

repetition suppression ； prediction errors ； attention ； event-related potentials

參考文獻

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