Department of Physiology, The University of Tokyo School of Medicine, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Cereb Cortex. 2012 Jul;22(7):1586-92. doi: 10.1093/cercor/bhr234. Epub 2011 Sep 5.
Coherent spontaneous blood oxygen level-dependent (BOLD) fluctuations have been intensely investigated as a measure of functional connectivity (FC) in the primate neocortex. BOLD-FC is commonly assumed to be constrained by the underlying anatomical connectivity (AC); however, cortical area pairs with no direct AC can also have strong BOLD-FC. On the mechanism generating FC in the absence of direct AC, there are 2 possibilities: 1) FC is determined by signal flows via short connection patterns, such as serial relays and common afferents mediated by a third area; 2) FC is shaped by collective effects governed by network properties of the cortex. In this study, we conducted functional magnetic resonance imaging in anesthetized macaque monkeys and found that BOLD-FC between unconnected areas depends less on serial relays through a third area than on common afferents and, unexpectedly, common efferents, which does not match the first possibility. By utilizing a computational model for interareal BOLD-FC network, we show that the empirically detected AC-FC relationships reflect the configuration of network building blocks (motifs) in the cortical anatomical network, which supports the second possibility. Our findings indicate that FC is not determined solely by interareal short connection patterns but instead is substantially influenced by the network-level cortical architecture.
相干自发血氧水平依赖（BOLD）波动一直被深入研究作为灵长类新皮层功能连接（FC）的测量指标。BOLD-FC 通常被认为受到潜在解剖连接（AC）的限制；然而，没有直接 AC 的皮质区域对也可能具有很强的 BOLD-FC。关于在没有直接 AC 的情况下产生 FC 的机制，有 2 种可能性：1）FC 是由通过第三区域介导的短连接模式（如串联中继和共同传入）的信号流决定的；2）FC 是由皮质网络属性控制的集体效应形成的。在这项研究中，我们在麻醉的猕猴中进行了功能磁共振成像，发现不相连区域之间的 BOLD-FC 与其说依赖于通过第三区域的串联中继，不如说依赖于共同传入和意外的共同传出，这与第一种可能性不一致。通过利用区域间 BOLD-FC 网络的计算模型，我们表明，经验检测到的 AC-FC 关系反映了皮质解剖网络中网络构建块（模体）的配置，这支持了第二种可能性。我们的发现表明，FC 不是仅由区域间短连接模式决定的，而是受到皮质网络水平结构的实质性影响。
