Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.
Department of Psychology, University of Toronto, Toronto, Canada.
Sci Rep. 2019 Oct 31;9(1):15757. doi: 10.1038/s41598-019-52219-0.
Children born very preterm (VPT) often demonstrate selective difficulties in working memory (WM), which may underlie academic difficulties observed in this population. Despite this, few studies have investigated the functional networks underlying WM in young children born VPT, a period when cognitive deficits become apparent. Using magnetoencephalography, we examined the networks underlying the maintenance of visual information in 6-year-old VPT (n = 15) and full-term (FT; n = 20) children. Although task performance was similar, VPT children engaged different oscillatory mechanisms during WM maintenance. Within the FT group, we observed higher mean whole-brain connectivity in the alpha-band during the retention (i.e. maintenance) interval associated with correct compared to incorrect responses. VPT children showed reduced whole-brain alpha synchrony, and a different network organization with fewer connections. In the theta-band, VPT children demonstrated a slight increase in whole-brain connectivity during WM maintenance, and engaged similar network hubs as FT children in the alpha-band, including the left dorsolateral prefrontal cortex and superior temporal gyrus. These findings suggest that VPT children rely on the theta-band to support similar task performance. Altered oscillatory mechanisms may reflect a less mature pattern of functional recruitment underlying WM in VPT children, which may affect the processing in complex ecological situations.
早产儿（VPT）出生的儿童通常表现出工作记忆（WM）的选择性困难，这可能是该人群中观察到的学业困难的基础。尽管如此，很少有研究调查过 VPT 幼儿 WM 的功能网络，这是认知缺陷变得明显的时期。我们使用脑磁图研究了 6 岁 VPT（n=15）和足月（FT；n=20）儿童视觉信息维持的网络。尽管任务表现相似，但 VPT 儿童在 WM 维持期间使用了不同的振荡机制。在 FT 组中，我们观察到在保留（即维持）间隔期间，与错误反应相比，正确反应时大脑整体连通性在 alpha 波段中更高。VPT 儿童表现出整体大脑 alpha 同步性降低，以及与 FT 儿童不同的网络组织，连接较少。在 theta 波段，VPT 儿童在 WM 维持期间表现出整体大脑连通性略有增加，并在 alpha 波段中与 FT 儿童使用相似的网络枢纽，包括左背外侧前额叶皮质和颞上回。这些发现表明，VPT 儿童依靠 theta 波段来支持类似的任务表现。振荡机制的改变可能反映了 VPT 儿童 WM 功能募集的不成熟模式，这可能会影响复杂生态情况下的处理。
