White matter microstructure in superior longitudinal fasciculus associated with spatial working memory performance in children.
During childhood and adolescence, ongoing white matter maturation in the fronto-parietal cortices and connecting fiber tracts is measurable with diffusion-weighted imaging. Important questions remain, however, about the links between these changes and developing cognitive functions. Spatial working memory (SWM) performance improves significantly throughout the childhood years, and several lines of evidence implicate the left fronto-parietal cortices and connecting fiber tracts in SWM processing. Here we report results from a study of 76 typically developing children, 7 to 13 years of age. We hypothesized that better SWM performance would be associated with increased fractional anisotropy (FA) in a left fronto-parietal network composed of the superior longitudinal fasciculus (SLF), the regional white matter underlying the dorsolateral pFC, and the posterior parietal cortex. As hypothesized, we observed a significant association between higher FA in the left fronto-parietal network and better SWM skills, and the effect was independent of age. This association was mainly accounted for by variability in left SLF FA and remained significant when FA measures from global fiber tracts or right SLF were included in the model. Further, the effect of FA in left SLF appeared to be mediated primarily by decreasing perpendicular diffusivity. Such associations could be related to individual differences among children in the architecture of fronto-parietal connections and/or to differences in the pace of fiber tract development. Further studies are needed to determine the contributions of intrinsic and experiential factors to the development of functionally significant individual differences in fiber tract structure.
MR-Department, Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital, Hvidovre, Denmark. martinvh@drcmr.dk
Martin
M
Vestergaard
Kathrine Skak
KS
Madsen
William F C
WF
Baaré
Arnold
A
Skimminge
Lisser Rye
LR
Ejersbo
Thomas Z
TZ
Ramsøy
Christian
C
Gerlach
Per
P
Akeson
Olaf B
OB
Paulson
Terry L
TL
Jernigan
D000293:Adolescent; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D016014:Linear Models; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009483:Neuropsychological Tests