Neuroimaging Research Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland.
Neuroimaging Research Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland.
Biol Psychiatry Cogn Neurosci Neuroimaging. 2021 Apr;6(4):459-469. doi: 10.1016/j.bpsc.2020.10.004. Epub 2020 Oct 19.
The nicotine withdrawal syndrome (NWS) includes affective and cognitive disruptions whose incidence and severity vary across time during acute abstinence. However, most network-level neuroimaging uses static measures of resting-state functional connectivity and assumes time-invariance and is thus unable to capture dynamic brain-behavior relationships. Recent advances in resting-state functional connectivity signal processing allow characterization of time-varying functional connectivity (TVFC), which characterizes network communication between networks that reconfigure over the course of data collection. Therefore, TVFC may more fully describe network dysfunction related to the NWS.
To isolate alterations in the frequency and diversity of communication across network boundaries during acute nicotine abstinence, we scanned 25 cigarette smokers in the nicotine-sated and abstinent states and applied a previously validated method to characterize TVFC at a network and a nodal level within the brain.
During abstinence, we found brain-wide decreases in the frequency of interactions between network nodes in different modular communities (i.e., temporal flexibility). In addition, within a subset of the networks examined, the variability of these interactions across community boundaries (i.e., spatiotemporal diversity) also decreased. Finally, within 2 of these networks, the decrease in spatiotemporal diversity was significantly related to NWS clinical symptoms.
Using multiple measures of TVFC in a within-subjects design, we characterized a novel set of changes in network communication and linked these changes to specific behavioral symptoms of the NWS. These reductions in TVFC provide a meso-scale network description of the relative inflexibility of specific large-scale brain networks during acute abstinence.
尼古丁戒断综合征（NWS）包括情感和认知障碍，其发生率和严重程度在急性戒断期间随时间变化而变化。然而，大多数网络级别的神经影像学使用静息态功能连接的静态测量，并假设时间不变性，因此无法捕捉动态的大脑-行为关系。静息态功能连接信号处理的最新进展允许对时变功能连接（TVFC）进行特征描述，它描述了在数据采集过程中重新配置的网络之间的网络通信。因此，TVFC 可能更全面地描述与 NWS 相关的网络功能障碍。
为了在急性尼古丁戒断期间隔离网络边界之间的频率和多样性变化，我们对 25 名吸烟的尼古丁满足者和戒断者进行了扫描，并应用了一种经过验证的方法来对大脑中的网络和节点水平的 TVFC 进行特征描述。
在戒断期间，我们发现不同模块化社区之间网络节点相互作用的频率（即时间灵活性）在全脑范围内降低。此外，在所检查的网络子集内，这些相互作用跨越社区边界的可变性（即时空多样性）也降低。最后，在其中 2 个网络中，时空多样性的降低与 NWS 临床症状显著相关。
我们使用了多个 TVFC 指标进行了个体内设计，对网络通信的一组新变化进行了特征描述，并将这些变化与 NWS 的特定行为症状联系起来。这些 TVFC 的减少为急性戒断期间特定大规模脑网络的相对灵活性提供了一种中尺度网络描述。
