Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Neuroimage. 2012 Aug 15;62(2):848-51. doi: 10.1016/j.neuroimage.2011.10.064. Epub 2011 Oct 28.
The discovery of functional MRI (fMRI), with the first papers appearing in 1992, gave rise to new categories of data that drove the development of new signal-processing strategies. Workers in the field were confronted with image time courses, which could be reshuffled to form pixel time courses. The waveform in an active pixel time-course was determined not only by the task sequence but also by the hemodynamic response function. Reference waveforms could be cross-correlated with pixel time courses to form an array of cross-correlation coefficients. From this array of numbers, colorized images could be created and overlaid on anatomical images. An early paper from the authors' laboratory is extensively reviewed here (Bandettini et al., 1993. Magn. Reson. Med. 30:161-173). That work was carried out using the vocabulary of vector algebra. Cross-correlation methodology was central to the discovery of functional connectivity MRI (fcMRI) by Biswal et al. (1995. Magn. Reson. Med. 34:537-541). In this method, a whole volume time course of images is collected while the brain is nominally at rest and connectivity is studied by cross-correlation of pixel time courses.
功能性磁共振成像（fMRI）的发现，其第一篇论文于 1992 年发表，产生了新的数据类别，推动了新的信号处理策略的发展。该领域的研究人员面临着图像时间序列，可以对其进行重新排列以形成像素时间序列。活跃像素时间序列中的波形不仅由任务序列决定，还由血液动力学响应函数决定。参考波形可以与像素时间序列进行互相关，形成一组互相关系数。从这个数组中，可以创建彩色图像并叠加在解剖图像上。作者实验室的早期论文在这里进行了广泛的综述（Bandettini 等人，1993. Magn. Reson. Med. 30:161-173）。这项工作使用了向量代数的词汇。Biswal 等人（1995. Magn. Reson. Med. 34:537-541）通过互相关方法发现了功能连接性磁共振成像（fcMRI）。在这种方法中，当大脑名义上处于休息状态时，会采集整个体积的图像时间序列，并通过像素时间序列的互相关来研究连接性。
