利用快速功能性核磁共振影像研究靜態人腦視覺區功能性連接

Abstract

傳統功能性核磁共振影像在研究人腦靜態的訊號時，多專注在低頻率（低於0.1Hz）的人腦訊號振動。在我們的實驗中，我們為了提高時間上的解析度，犧牲了影像的涵蓋範圍，利用單張快速迴訊平面造影(TR 為0.1秒)的技術，以專注於研究人腦左右視覺區域之間的功能性連接。快速掃描技術提供給我們很高的取樣頻率，有助於我們在分析訊號時排除生理雜訊的干擾，同時又能讓我們研究更高頻率上的振動。在實驗中，我們使用了時域上的相關性分析和訊號包絡的相關性分析來衡量在不同頻率下人腦左右視覺區的功能性連接。我們的結果證明，一如傳統靜態人腦功能性核磁共振影像實驗的結果，人腦的左右視覺區靜態的訊號，在0.08Hz以下是高度相關的。同時，在0.1Hz到0.2Hz的頻率帶內，這兩個視覺區的訊號也高度相關。

Conventional resting-state fMRI often looks for spontaneous BOLD signals at frequencies below 0.1Hz. In this study, we used high-speed single-slice EPI with TR = 100 ms to investigate the functional connectivity between hemispheric visual cortex. We sacrificed the coverage of the brain without compromising the spatial resolution in order to achieve a high sampling rate (10 Hz). With the high sampling rate, we were able to prevent the physiological noise from aliasing with the BOLD signals of interest and investigate the spontaneous BOLD signal at frequencies above 0.1Hz. We used time series correlation and oscillatory envelope correlation to assess the functional connectivity. Our results show that left visual cortex and right visual cortex are highly correlated at the frequency band lower than 0.08Hz and at the frequency band between 0.1Hz and 0.2Hz.