Combined analysis of DTI and fMRI data reveals a joint maturation of white and grey matter in a fronto-parietal network.

“…(WM) consists largely of densely packed myelinated neuronal axons, and efficient cognitive processing relies on the integrity of these pathways (Olesen et al. 2003; Tuch et al. 2005; Liston et al. 2006; Fields 2008; Kennedy and Raz 2009a; Perry et al. 2009; Westlye, Walhovd, Bjørnerud, et al.…”

“More recently, diffusion tensor imaging (DTI) studies investigating the development of white-matter pathways have shown increase in anisotropy [10–12], decrease in overall diffusion [13], and maturation in major white-matter fiber tracts [14–19], with age.”

“Furthermore, it was recently shown that the FA in the superior frontal lobe is directly correlated with brain activity in the superior frontal sulcus and intraparietal cortex in children ( Olesen, Nagy, Westerberg, & Klingberg, 2003 ).”

“Other studies have combined white matter changes and functional development (for example, in a working memory task; Olesen et al., 2003).”

“Studies combining diffusion tensor imaging (to study WM maturation) and fMRI have shown evidence for parallel age-related maturational processes of progressive myelination of frontal and parietal association areas and functional development in the same brain areas in the context of working memory [Olesen et al., 2003].”

“…including the corpus callosum, and the inferior fronto-occipital, superior longitudinal and uncinate fasciculi, during late childhood, adolescence and early adulthood (Olesen et al. 2003; Snook et al. 2005; Zhang et al. 2005; Liston et al. 2006; Eluvathingal et al. 2007; Giorgio et al. 2008).”

“White matter brain structure underlies cognitive abilities (Olesen et al., 2003), as well as several neurological and psychiatric disorders and normal aging (Moseley, 2002; Kanaan et al., 2005; Chua et al., 2008).”

“Similar combined DTI and fMRI analytical approaches have been used in adults [44 ].”

“Visuospatial working memory capacity is linked to a fronto-intraparietal network (Olesen et al. 2003), whereas delayed visual memory is linked to temporal and occipital FA (Mabbott et al.”

“Continued myelination in turn enhances the ability of prefrontal cortex to effectively influence on the rest of the brain (Chugani, Phelps, & Mazziotta, 1987; Olesen et al., 2003; Thatcher, 1991).”

“…lobe and adjacent white matter FA is consistent with a study in children and adolescents aged 8–18 years in which a combined DTI and functional MRI (FMRI) analysis revealed a joint maturation of these two areas as part of a functional network underlying workingmemory (Olesen et al., 2003).”

“…between structural and functional changes is currently not well understood as few studies have directly compared structural and functional data within the same individuals (Cohen Kadosh et al., 2013; Dumontheil et al., 2010b; Lu et al., 2009; Olesen et al., 2003; van den Bos et al., 2012b).”

“When the number of participants was increased to 23, we also found a significant, positive correlation in the head of the caudate nucleus in the left hemisphere (Olesen et al., 2003).”

“Working memory capacity is positively correlated with the development of connectivity between superior frontal and parietal lobes (Nagy et al., 2004; Olesen et al., 2003).”

“…of axons beyond early childhood (Yakovlev et al., 1967; Paus et al., 1999) and synaptic pruning (Huttenlocher, 1979; Rakic et al., 1986) enhance the efficiency of neuronal transmission throughout distributed circuitries (Olesen et al., 2003; Boorman et al., 2007; Stufflebeam et al., 2008).”

“It increases during development (Gathercole et al., 2004) and those age-related increases relate to frontal-parietal white-matter maturation (Nagy et al., 2004) and activation (Olesen et al., 2003).”

“white matter microstructure are associated with magnitudes of brain function supporting executive function (Olesen et al., 2003) via their effects on network integration (Stevens et al.”

“, 2008), working memory (Nagy et al., 2004; Olesen et al., 2003), inhibitory control (Liston et al.”

“Developmental reductions in gray matter also continue through adolescence in cortical association areas, notably in frontal and temporal regions (Gogtay et al. 2004; Toga et al. 2006) and improvements in white matter integrity extend from frontal to parietal regions (Olesen et al. 2003).”

“The less extensive DLPFC activation in children may result from a limitation in both the localized computations within the DLPFC, because of insufficient synaptic pruning, and in less developed connections between the DLPFC and caudate nuclei (Olesen et al., 2003; Yakovlev & Lecours, 1967).”

“…are consistently higher in cortical gray matter than in white matter regions (Hall et al., 2002), but combined analysis of DTI and fMRI data showed a positive correlation between maturation of white matter and BOLD response in several cortical and subcortical regions (Olesen et al., 2003).”

“Finally, FA values in the ACR have been shown to correlate with working memory performance (Nagy et al., 2004; Olesen et al., 2003 ).”

“These findings do, however, highlight the importance of regional connections for memory function (Alexander and Stuss, 2000; Johnson et al., 2002; Olesen et al., 2003).”

“In infancy, increased FA correlates with decreased grey matter density in cortical areas that may reflect synaptic pruning (Klingberg et al. 1999; Olesen et al. 2003).”

“during cognitive control tasks [21, 89] and with activation in adjacent grey matter regions [89].”

“Analytical methods using a combination of DTI and fMRI have also demonstrated a positive correlation between the maturation of prefrontal-parietal connectivity and performance on working memory tasks (Olesen et al. 2003).”

“In another study, Olesen et al. (2003) combined DTI (structural) and fMRI (functional) analyses in 8–18 year olds and demonstrated that enhanced integrity of connections between superior frontal sulcus, inferior parietal lobe, and caudate were found to correlate with BOLD response and…”

“18 years, Olesen and colleagues [56] have found that FA values in frontoparietal white matter correlated with BOLD activation in closely located gray”

“…with working memory, executive functioning, or memory demands that may be linked to white matter integrity and development (Nagy et al., 2004; Olesen et al., 2003; Zahr et al., 2009) were also administered and examined in correlation analyses: Wechsler Adult Intelligence Scale-Third Edition…”

“In addition, it has been suggested that highly integrated white matter pathways underlie increased functional connectivity between relevant brain regions and increased functional activation in relevant brain areas (Au Duong et al., 2005, Olesen et al., 2003).”

“During the attainment of increased working memory capacity as children get older the superior frontal sulcus (prefrontal cortex) and the intraparietal sulcus (parietal cortex) show a greater degree of task-related activation and have increased white matter connectivity (Klingberg et al., 2002; Kwon et al., 2002; Olese…”

“To account for development in examining brain/ behavior relations, researchers have controlled for age when calculating correlations between DTI indices and behavioral performance (Liston et al., 2006; Nagy et al., 2004; Olesen et al., 2003; Schmithorst et al., 2005).”

“These results are also consistent with prior fMRI studies that implicate the left hemisphere in SWM functions in children and adolescents (Schweinsburg et al. 2005; Olesen et al., 2003; Klingberg et al., 2002).”

“CC and the cortico-spinal tract (Baird et al., 2005; Jang et al., 2005; Jerger et al., 2004; Munakata et al., 2006; Okumura et al., 2005; Olesen et al., 2003).”

“However, in the longitudinal analysis, FA in white matter tracts and activity in caudate predicted future WM capacity.”

“Furthermore , development of visuospatial WM is related to increased activity in these cortical areas (Klingberg and others 2002; Kwon and others 2002; Olesen and others 2003) and maturation of frontoparietal white matter (Nagy and others 2004).”

“Furthermore, the development of working memory in childhood and adolescence suggests reliance on the maturation of an integrated fronto-parietal network in both grey and white matter, as indicated by a study of (spatial) working memory combining DTI and functional MRI (fMRI) (Olesen et al., 2003).”

“Reports have validated that there are networks of brain regions where maturation of white matter and changes in functional activity show similar developmental trends during human childhood (Olesen et al., 2003), thus it is plausible to assume that functional and anatomical brain properties covary across subjects, an a…”

“…to the pattern of findings identified in several association and commissural pathways in typically developing children and adolescents (Alexander et al., 2007; Ashtari et al., 2005; Eluvathingal et al., 2007; Nagy et al., 2004; Neil et al., 2002; Olesen et al., 2003; Schmithorst et al., 2002).”

“…in older adults correlated with callosal FA (Table 5) is consistent with other studies linking white matter measures to both to fMRI activity (Olesen et al. 2003; Persson et al. 2006; Putnam et al. 2008; Mazerolle et al. 2010) as well as resting state and task-related functional connectivity…”

“Although recent data in adult subjects suggest a correlation between structure and function, we had neithercomplete volumetric data nor diffusion tensor imaging in this cohort of children ( Olesen et al., 2003; Saur et al., 2008).”

“More naturalistic tests of mentalising, on which adolescents do not show ceiling performance, are needed to test this hypothesis, as well as studies combining measures of functional connectivity during mentalising tasks with static anatomical measures of grey and white matter volume and white matter integrity (e.g. vo…”

“Development of brain function is likely to be closely linked to structural brain development (Olesen et al., 2003).”

“Different subcortical structures have been implicated in working memory in developmental samples, including caudate, putamen, hippocampus, and cerebellum (Pangelinan et al., 2011; Finn et al., 2010; Ciesielski et al., 2006; Olesen et al., 2003), but associations in specific subcortical regions are less consistently ob…”

“Importantly, a number of developmental studies have drawn links between increased WM volume and age-related improvements in cognitive or behavioral performance (Klingberg, 2006; Klingberg et al., 1999; Liston et al., 2006; Nagy et al., 2004; Olesen et al., 2003).”

“Multiple previous studies that combined function and structure (Camara et al., 2010; Olesen et al., 2003; Rykhlevskaia et al., 2008; Sui et al., 2012) provide support for the assumption that components decomposed from each modality have some degree of correlation between their mixing pro fi les…”

“…caudate nucleus and its connections with the prefrontal cortex), maturation continues into adolescence, thus challenging the view of a ‘‘developmental invariance’’ of implicit in contrast with explicit memory (Casey et al., 2004; Olesen et al., 2003; Sowell et al., 1999; Yakovlev & Lecours, 1967).”

“…February 2010 doi: 10.3389/neuro.05.002.2010 et al., 2007; Niogi et al., 2008b), visual attention (Tuch et al., 2005; Madden et al., 2006), alerting (Nestor et al., 2007), and memory (Olesen et al., 2003; Niogi and McCandliss, 2006; Niogi et al., 2008b; Schiavone et al., 2009; Zahr et al., 2009).”

“Development of brain function is likely to be closely linked to structural brain development (Olesen et al., 2003).”

“This result is consistent with previous studies showing slow maturation of longdistance white matter tracts [53,54], including those linking prefrontal and posterior parietal cortices [55,56,57].”

“Both factors increased oligodendrocytes, a cell type that makes up the critical components of white matter microstructure, therefore suggesting possible improvements in working memory dependent on the PFC (Olesen et al., 2003).”

“An early working memory study from Olesen et al. (2003) tried to reveal whether the developments of structure (white matter) and function (brain activity) follow the similar trend.”

“…matter microstructure has previously been linked to working memory development in other studies (Burzynska et al., 2011; Karlsgodt et al., 2008; Olesen et al., 2003; Vestergaard et al., 2010), but the study by Niogi and McCandliss (2006) did not find any relationship between SLF microstructure…”

“Multiple previous studies that combined function and structure (Olesen et al., 2003; Rykhlevskaia et al., 2008; Camara et al., 2010; Sui et al., 2012b) provide support for the assumption that components decomposed from each modality have some degree of correlation between their mixing profiles…”

“These studies have demonstrated that children recruit superior frontal and parietal cortical regions during task performance (Thomas et al.,1999; Nelson et al., 2000; Klingberg et al., 2002; Kwon et al., 2002; Olesen et al., 2003), a pattern of activation similar to that found in adults, where numerous investigations…”

“Anatomical and functional magnetic resonance imaging (fMRI ) has been used to map structural and physiological changes associated with cognitive development during childhood ( Olesen, Nagy, Westerberg, & Klingberg, 2003; Bunge, Dudukovic, Thomason, Vaidya, & Gabrieli, 2002; Klingberg, Forssberg, & Westerberg, 2002; Ca…”