以獨立成分分析法比較聲音刺激下任務複雜度之腦部活性研究

Using Independent Component Analysis to Compare Brain Activity of Task Complexity under Sound Stimulation

大腦對外部刺激的感官訊號做出反應，而聽覺聲音刺激也會對腦部產生一定影響，甚至是影響專注力，為觀察聲音刺激對大腦會造成何種影響，本研究設計了一套聲音刺激實驗，含有忽略、按鍵、計數、按鍵與計數四種不同的實驗任務，來研究聲音刺激與大腦多工的相關性，並且以獨立成分分析法（Independent component analysis, ICA）進行分析，再以失匹配負波（Mismatch negativity, MMN）與事件相關頻譜震盪（Event- related spectral perturbation, ERSP）進行觀察，MMN 為大腦對刺激自動處理的機制。結果顯示ERSP 顯示了大腦在一定時間內產生的能量振盪，在按鍵實驗中，可以看到反同步化反應（Event-related desynchronization, ERD）從標準刺激的高頻轉移至偏差刺激的低頻ERD 反應，顯示大腦對於偏差刺激進行更加專注的反應，相對的在同步化反應（Event-related synchronization, ERS）的佔有率，偏差刺激也同樣高於標準刺激；另外在計數實驗中，從偏差刺激的ERD 反應中可以觀察到指向反應的轉移過程。在按鍵計數實驗中，其中在偏差刺激的ERS 反應高於標準刺激的ERS 反應的趨勢。另外ERD 反應範圍相較於ERS 反應廣泛，並且同時進行兩種任務之專注力會造成大腦在反同步化及同步化之間反應震盪。

The brain responds to sensory signals from external stimuli, and auditory sounds will have a certain impact on the brain and even affect attention. In order to observe the impact of sound stimulation on the brain, this study designed a set of sound stimulus including inattention sound (IS), sound button (SB), sound count (SC), and sound button count (SBC), used independent component analysis (ICA), mismatch negativity (MMN), and event-related spectral perturbation (ERSP) to study the relation between sound stimulation and brain multitasks. MMN is the brain’s mechanism of automatic processing. The results show that ERSP generates the energy oscillations on the brain within a certain period of time. In the SB experiment, the event-related desynchronization (ERD) has shifted from the high frequency response of the standard stimulus to the low frequency response of the deviation stimulus. The brain responds more attention in deviation stimulus, and the appearance rate of event-related synchronization (ERS) in deviation stimuli is relatively higher than that of standard stimulus. In SC experiment, the ERD response of deviation stimuli could observe the transfer process. In the SBC experiment, the ERS response of the deviation stimulus is higher than that of the standard stimulus. In addition, the range of the ERD response is wider than that of the ERS response and the attention of the subject executing two tasks at the same time causes the oscillation response between ERD and ERS.