Zhang Nanyin, Zhu Xiao-Hong, Chen Wei
Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Magn Reson Med. 2005 Aug;54(2):258-63. doi: 10.1002/mrm.20512.
A paired-stimuli paradigm combined with fMRI was utilized to study the effect of gradient acoustic noise on fMRI response in the human primary visual cortex (V1) in terms of the auditory-visual cross-modal neural interaction. The gradient noise generated during the fMRI acquisition was used as the primary stimulus, and a single flashing light was used as the secondary stimulus. An interstimulus interval (ISI) separated the two. Six tasks were designed with different ISIs ranging from 50 to 700 ms. Both BOLD signal intensity and the number of activated pixels in V1 were analyzed and examined, and they showed a significant reduction when the gradient noise preceded the flashing light by approximately 300 ms. These results indicate that the gradient acoustic noise generated during fMRI acquisitions does interfere with neural behavior and the BOLD signal in the human visual cortex. This interference is modulated by the delay between the gradient noise and visual stimulation, and it can be studied quantitatively when the stimulation paradigm is designed appropriately. This study provides evidence of the auditory-visual interaction during fMRI studies, and the results should have an impact on fMRI applications.
采用配对刺激范式结合功能磁共振成像（fMRI），从听觉-视觉跨模态神经交互的角度，研究梯度声噪声对人类初级视觉皮层（V1）中fMRI反应的影响。将fMRI采集过程中产生的梯度噪声用作主要刺激，将单个闪光用作次要刺激。刺激间隔（ISI）将两者分开。设计了六个任务，其ISI范围从50到700毫秒不等。对V1中的血氧水平依赖（BOLD）信号强度和激活像素数量进行了分析和检查，结果显示，当梯度噪声比闪光提前约300毫秒时，两者均显著降低。这些结果表明，fMRI采集过程中产生的梯度声噪声确实会干扰人类视觉皮层中的神经行为和BOLD信号。这种干扰受梯度噪声与视觉刺激之间延迟的调节，并且当刺激范式设计适当时，可以进行定量研究。本研究为fMRI研究期间的听觉-视觉交互提供了证据，其结果应会对fMRI应用产生影响。
