Department of Psychiatry and Psychotherapy III, University of Ulm, Ulm, Germany.
PLoS One. 2011;6(11):e27050. doi: 10.1371/journal.pone.0027050. Epub 2011 Nov 4.
Functional connectivity is a property of the resting state that may provide biomarkers of brain function and individual differences. Classically, connectivity is estimated as the temporal correlation of spontaneous fluctuations of BOLD signal. We investigated differences in connectivity estimated from the BOLD and CBF signal present in volumes acquired with arterial spin labeling technique in a large sample (N = 265) of healthy individuals. Positive connectivity was observable in both BOLD and CBF signal, and was present in the CBF signal also at frequencies lower than 0.009 Hz, here investigated for the first time. Negative connectivity was more variable. The validity of positive connectivity was confirmed by the existence of correlation across individuals in its intensity estimated from the BOLD and CBF signal. In contrast, there was little or no correlation across individuals between intensity of connectivity and mean perfusion levels, suggesting that these two biomarkers correspond to distinct sources of individual differences.
功能连接是静息态的一种特性，它可能为大脑功能和个体差异提供生物标志物。传统上，连接性是通过对血氧水平依赖（BOLD）信号的自发波动的时间相关性来估计的。我们在一个大型健康个体样本（N=265）中，研究了从动脉自旋标记技术采集的体积中 BOLD 和 CBF 信号估计的连接性差异。在 BOLD 和 CBF 信号中都可以观察到正连接性，并且在 CBF 信号中也存在低于 0.009 Hz 的频率，这是首次进行的研究。负连接性更为多变。正连接性的有效性通过从 BOLD 和 CBF 信号中估计其强度的个体间存在相关性得到了证实。相比之下，在连接性强度和平均灌注水平之间，个体间的相关性很小或不存在，这表明这两个生物标志物对应于个体差异的不同来源。
