Eryurek Kardelen, Ulasoglu-Yildiz Cigdem, Matur Zeliha, Öge A Emre, Gürvit Hakan, Demiralp Tamer
Istanbul University, Aziz Sancar Institute of Experimental Medicine, Department of Neuroscience, Istanbul, Turkey; Istanbul University, Graduate School of Health Sciences, Istanbul, Turkey.
Istanbul University, Hulusi Behçet Life Sciences Research Center, Neuroimaging Unit, Capa, Istanbul, Turkey.
Cortex. 2022 Jan;146:89-105. doi: 10.1016/j.cortex.2021.10.006. Epub 2021 Nov 19.
Motor sequence learning (MSL) paradigms are often used to investigate the neural processes underlying the acquisition of complex motor skills. Behavioral and neuroimaging studies have indicated an early stage in which spatial learning is prominent and a late stage of automatized performance after multiple training periods. Functional magnetic resonance imaging (fMRI) studies yielded both decreased and increased activations of the sensorimotor and association areas. However, task-negative and task-positive intrinsic connectivity networks (ICNs), the default mode (DMN) and dorsal attention (DAN) networks involved in governing attention demands during various task conditions were not specifically addressed in most studies. In the present fMRI study, a visually guided MSL (VMSL) task was used for bringing roles of visuospatial and motor attention into foreground in order to investigate the role of attention-related ICNs in MSL. Seventeen healthy, right-handed participants completed training and test sessions of VMSL during fMRI on the 1st day. Then, after daily training for three consecutive days outside the scanner, they were re-tested during the 5th day's scanning session. When test session after early learning period was compared with training session, activation decrease was observed in the occipito-temporal fusiform cortex, while task-related suppression of DMN was reduced. Reduced deactivation after early learning was correlated with decreased error rates. After late learning stage we observed activation decreases in bilateral superior parietal lobules of task-positive DAN, dorsal precunei, and cerebellum. Reduced activity in left posterior parietal and right cerebellar regions were correlated with gains in speed, error rate, respectively. This dissociation in activity changes of DMN and DAN related areas suggests that DAN shows high contribution during both early and late MSL stages, possibly due to attention requirement for automatization of spatial and temporal aspects of motor sequence. In contrast, spatial learning occurring during early MSL stage was sufficient for releasing DMN resources.
运动序列学习（MSL）范式常用于研究复杂运动技能习得背后的神经过程。行为学和神经影像学研究表明，在多个训练阶段后，存在一个空间学习突出的早期阶段和一个自动化表现的后期阶段。功能磁共振成像（fMRI）研究显示，感觉运动区和联合区的激活既有减少也有增加。然而，大多数研究并未专门探讨任务负性和任务正性固有连接网络（ICN），即参与在各种任务条件下控制注意力需求的默认模式（DMN）和背侧注意（DAN）网络。在本fMRI研究中，使用了视觉引导的MSL（VMSL）任务，以使视觉空间和运动注意力的作用凸显出来，从而研究与注意力相关的ICN在MSL中的作用。17名健康的右利手参与者在第1天的fMRI扫描期间完成了VMSL的训练和测试环节。然后，在连续三天在扫描仪外进行每日训练后，他们在第5天的扫描环节中再次接受测试。当将早期学习阶段后的测试环节与训练环节进行比较时，枕颞梭状回皮质出现激活减少，而DMN的任务相关抑制作用减弱。早期学习后去激活的减少与错误率的降低相关。在后期学习阶段后，我们观察到任务正性DAN的双侧顶上小叶、背侧楔前叶和小脑出现激活减少。左后顶叶和右小脑区域的活动减少分别与速度提高和错误率降低相关。DMN和DAN相关区域活动变化的这种分离表明，DAN在MSL的早期和后期阶段都有很大贡献，这可能是由于运动序列的空间和时间方面自动化对注意力的需求所致。相比之下，MSL早期阶段发生的空间学习足以释放DMN资源。
