Sethi Sarab S, Zerbi Valerio, Wenderoth Nicole, Fornito Alex, Fulcher Ben D
Department of Mathematics, Imperial College London, London, United Kingdom.
Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zurich, Switzerland.
Chaos. 2017 Apr;27(4):047405. doi: 10.1063/1.4979281.
Brain dynamics are thought to unfold on a network determined by the pattern of axonal connections linking pairs of neuronal elements; the so-called connectome. Prior work has indicated that structural brain connectivity constrains pairwise correlations of brain dynamics ("functional connectivity"), but it is not known whether inter-regional axonal connectivity is related to the intrinsic dynamics of individual brain areas. Here we investigate this relationship using a weighted, directed mesoscale mouse connectome from the Allen Mouse Brain Connectivity Atlas and resting state functional MRI (rs-fMRI) time-series data measured in 184 brain regions in eighteen anesthetized mice. For each brain region, we measured degree, betweenness, and clustering coefficient from weighted and unweighted, and directed and undirected versions of the connectome. We then characterized the univariate rs-fMRI dynamics in each brain region by computing 6930 time-series properties using the time-series analysis toolbox, hctsa. After correcting for regional volume variations, strong and robust correlations between structural connectivity properties and rs-fMRI dynamics were found only when edge weights were accounted for, and were associated with variations in the autocorrelation properties of the rs-fMRI signal. The strongest relationships were found for weighted in-degree, which was positively correlated to the autocorrelation of fMRI time series at time lag τ = 34 s (partial Spearman correlation ρ=0.58), as well as a range of related measures such as relative high frequency power (f > 0.4 Hz: ρ=-0.43). Our results indicate that the topology of inter-regional axonal connections of the mouse brain is closely related to intrinsic, spontaneous dynamics such that regions with a greater aggregate strength of incoming projections display longer timescales of activity fluctuations.
大脑动力学被认为是在由连接神经元对的轴突连接模式所决定的网络上展开的;即所谓的连接组。先前的研究表明,大脑结构连接性会限制大脑动力学的成对相关性(“功能连接性”),但尚不清楚区域间轴突连接性是否与各个脑区的内在动力学相关。在这里,我们使用来自艾伦小鼠脑连接图谱的加权、有向中尺度小鼠连接组以及在18只麻醉小鼠的184个脑区测量的静息态功能磁共振成像(rs-fMRI)时间序列数据来研究这种关系。对于每个脑区,我们从连接组的加权和未加权、有向和无向版本中测量了度、介数和聚类系数。然后,我们使用时间序列分析工具箱hctsa计算6930个时间序列属性,对每个脑区的单变量rs-fMRI动力学进行了表征。在校正区域体积变化后,仅当考虑边权重时,才发现结构连接性属性与rs-fMRI动力学之间存在强而稳健的相关性,并且这些相关性与rs-fMRI信号的自相关属性变化有关。发现加权入度的关系最强,它与滞后时间τ = 34 s时fMRI时间序列的自相关呈正相关(偏斯皮尔曼相关系数ρ = 0.58),以及一系列相关指标,如相对高频功率(f > 0.4 Hz:ρ = -0.43)。我们的结果表明,小鼠脑区间轴突连接的拓扑结构与内在的自发动力学密切相关,即传入投射总强度较大的区域表现出更长时间尺度的活动波动。