ORCID Profile
0000-0003-4833-4782
Current Organisations
University of Sydney
,
Deakin University - Melbourne Burwood Campus
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Publisher: Elsevier BV
Date: 02-2021
Publisher: Informa UK Limited
Date: 11-2023
Publisher: Wiley
Date: 14-06-2023
DOI: 10.1111/EJN.16059
Abstract: Neuroimaging resting state paradigms have revealed synchronised oscillatory activity is present even in the absence of completing a task or mental operation. One function of this neural activity is likely to optimise the brain's sensitivity to forthcoming information that, in turn, likely promotes subsequent learning and memory outcomes. The current study investigated whether this extends to implicit forms of learning. A total of 85 healthy adults participated in the study. Resting state electroencephalography was first acquired from participants before they completed a serial reaction time task. On this task, participants implicitly learnt a visuospatial‐motor sequence. Permutation testing revealed a negative correlation between implicit sequence learning and resting state power in the upper theta band (6–7 Hz). That is, lower levels of resting state power in this frequency range were associated with superior levels of implicit sequence learning. This association was observed at midline‐frontal, right‐frontal and left‐posterior electrodes. Oscillatory activity in the upper theta band supports a range of top‐down processes including attention, inhibitory control and working memory, perhaps just for visuospatial information. Our results may be indicating that disengaging theta‐supported top‐down attentional processes improves implicit learning of visuospatial‐motor information that is embedded in sensory input. This may occur because the brain's sensitivity to this type of information is optimally achieved when learning is driven by bottom‐up processes. Moreover, the results of this study further demonstrate that resting state synchronised brain activity influences subsequent learning and memory.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.RIDD.2014.07.042
Abstract: The present study aimed to provide preliminary insight into the integrity of motor imagery (MI) in adults with probable developmental coordination disorder (pDCD). Based on a strong body of evidence indicating that paediatric s les of DCD often experience difficulties engaging MI, we hypothesised that young adults with pDCD would demonstrate similar difficulties. The performance of 12 young adults (19-35 years) with pDCD was compared to 47 age-matched controls on a traditional mental hand rotation task. Mean inverse efficiency scores were generated for each participant by iding each participant's mean RT by their proportion of correct responses at each of the stimuli presentation conditions. Preliminary analysis revealed that the performance profiles of in iduals with pDCD and age-matched controls showed evidence of being constrained by the biomechanical and postural constraints of real movement, suggesting that both groups engaged in an embodied (MI) strategy to complete the task. Despite engaging in a MI strategy, however, young adults with pDCD were nonetheless significantly less efficient when doing so, shown by significant main effects for group on all group efficiency comparisons. Based on the assumption that MI provides insight into the internal 'neural' action representation that precedes action, we argue that the less efficient MI performance demonstrated by young adults with pDCD may indicate inefficiencies engaging or implementing internal action representations. Implications and directions for future research are discussed.
Publisher: Cambridge University Press (CUP)
Date: 02-2017
DOI: 10.1017/S1355617717000029
Abstract: Objectives: It is unclear whether the primary motor cortex (PMC) is involved in the mental simulation of movement [i.e., motor imagery (MI)]. The present study aimed to clarify PMC involvement using a highly novel adaptation of the hand laterality task (HLT). Methods: Participants were administered single-pulse transcranial magnetic stimulation (TMS) to the hand area of the left PMC (hPMC) at either 50 ms, 400 ms, or 650 ms post stimulus presentation. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous via electromyography. To avoid the confound of gross motor response, participant response (indicating left or right hand) was recorded via eye tracking. Participants were 22 healthy adults (18 to 36 years), 16 whose behavioral profile on the HLT was consistent with the use of a MI strategy (MI users). Results: hPMC excitability increased significantly during HLT performance for MI users, evidenced by significantly larger right hand MEPs following single-pulse TMS 50 ms, 400 ms, and 650 ms post stimulus presentation relative to baseline. Subsequent analysis showed that hPMC excitability was greater for more complex simulated hand movements, where hand MEPs at 50 ms were larger for biomechanically awkward movements (i.e., hands requiring lateral rotation) compared to simpler movements (i.e., hands requiring medial rotation). Conclusions: These findings provide support for the modulation of PMC excitability during the HLT attributable to MI, and may indicate a role for the PMC during MI. ( JINS , 2017, 23 , 185–193)
Publisher: Springer International Publishing
Date: 14-10-2023
Publisher: Informa UK Limited
Date: 05-2013
DOI: 10.1080/00222895.2013.785927
Abstract: Neurocomputational models of reaching indicate that efficient purposive correction of movement midflight (e.g., online control) depends on one's ability to generate and monitor an accurate internal (neural) movement representation. In the first study to test this empirically, the authors investigated the relationship between healthy young adults' implicit motor imagery performance and their capacity to correct their reaching trajectory. As expected, after controlling for general reaching speed, hierarchical regression demonstrated that imagery ability was a significant predictor of hand correction speed that is, faster and more accurate imagery performance associated with faster corrections to reaching following target displacement at movement onset. They argue that these findings provide preliminary support for the view that a link exists between an in idual's ability to represent movement mentally and correct movement online efficiently.
Publisher: Cold Spring Harbor Laboratory
Date: 04-2022
DOI: 10.1101/2022.03.30.22273215
Abstract: Corpus callosum anomalies are commonly noted in autism spectrum disorder (ASD). Given the complexity of its microstructural architecture, with crossing fibers projecting throughout, we applied fixel-based analysis to probe white matter micro- and macrostructure within this region. As ASD is a neurodevelopmental condition with noted abnormalities in brain growth, age was also investigated. Data for participants with (N=54) and without (N=50) ASD, aged 5-34 years, were obtained from the Autism Brain Imaging Data Exchange-II (ABIDE-II). Within each site, indices of fiber density (FD), fiber cross-section (FC), and combined fiber density and cross-section (FDC) were compared between those groups. Young adolescents with ASD (age = 11.19 ± 7.54) showed reduced macroscopic FC and FDC compared to age-matched neurotypical controls (age = 10.04 ± 4.40). Reduced FD and FDC was noted in a marginally older ASD (age 13.87 ± 3.15) cohort compared to matched controls (age = 13.85 ± 2.90). Among the oldest cohorts, a non-significant trend indicated reduced FD in older adolescents/young adults with ASD (age = 17.07 ± 3.56) compared to controls (age = 16.55 ± 2.95). There was a positive correlation between age and callosal mean FC and FDC in the youngest cohort. When stratified by diagnosis, this finding remained only for the ASD s le. White matter aberration appears greatest among younger ASD cohorts. In older adolescents and young adults, less of the corpus callosum seems affected. This supports the suggestion that some early neuropathophysiological indicators in ASD may dissipate with age.
Publisher: Springer International Publishing
Date: 14-10-2024
Publisher: Springer International Publishing
Date: 14-10-2024
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.HUMOV.2013.02.008
Abstract: Rapid online control during reaching has an important bearing on movement accuracy and flexibility. It is surprising then that few studies have investigated the development of rapid online control in children. In this study, we were particularly interested in age-related changes in the nature of motor control in response to visual perturbation. We compared the performance of younger (6-7 years of age), mid-aged (8-9), and older (10-12) children, as well as healthy young adults using a double-step reaching task. Participants were required to make target-directed reaching movements in near space, while also responding to visual perturbations that occurred at movement onset for a small percentage of trials. Results showed that both the older and mid-aged children corrected their reaching in response to the unexpected shifts in target location significantly faster than younger children, manifest by reduced time to correction. In turn, the responses of adults were faster than older children in terms of movement time and on kinematic measures such as time to correction and time to peak velocity. These results indicate that the capacity to utilize forward estimates of limb position in the service of online control of early perturbations to ballistic (or rapid) reaching develops in a non-linear fashion, progressing rapidly between early and middle childhood, showing a degree of stability over mid and later childhood, but then evidence for continued refinement between childhood and young adulthood. The pattern of change after childhood and into early adolescence requires further investigation, particularly during the rapid phase of physical growth that accompanies puberty.
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 05-2022
DOI: 10.1016/J.BPSC.2022.01.001
Abstract: Attention deficit hyperactivity disorder (ADHD) is a prevalent childhood neurodevelopmental disorder. Given the profound brain changes that occur across childhood and adolescence, it is important to identify functional networks that exhibit differential developmental patterns in children with ADHD. This study sought to examine whether children with ADHD exhibit differential developmental trajectories in functional connectivity, compared to typically developing controls using a network-based approach. 175 in iduals (91 children with ADHD and 84 non-ADHD controls) participated in a longitudinal neuroimaging study with up to three waves (173 total resting state scans children with ADHD and 197 in controls) between the ages 9 and 14. We adopted Network-Based Statistics to identify connected components with trajectories of development that differed between groups. In iduals with ADHD exhibited differential developmental trajectories compared to typically developing controls in cortico-limbic and visual-higher order cognitive networks. A pattern of reduction in functional connectivity between cortico-limbic networks was seen across development in controls that was not present in the ADHD group. Conversely, the ADHD group showed a significant decrease in connectivity between predominantly visual and higher order cognitive networks, that were not displayed in the control group. Our findings show that the developmental trajectories in ADHD children are characterized by a subnetwork involving different trajectories predominantly between cortico-limbic and visual-higher order cognitive network connections. These findings highlight the importance of examining the longitudinal maturational course to understand the development of functional connectivity networks in children with ADHD.
Publisher: Wiley
Date: 07-11-2021
DOI: 10.1002/JNR.24969
Abstract: The mirror neuron system (MNS) has been theorized to play a neurobiological role in a number of social cognitive abilities and is commonly indexed putatively in humans via interpersonal motor resonance (IMR) and mu suppression. Although both indices are thought to measure similar neuronal populations (i.e., "mirror neurons"), it has been suggested that these methods are unrelated, and therefore, incompatible. However, prior studies reporting no relationships were typically conducted in small and underpowered s les. Thus, we aimed to investigate this potential association in a large s le of neurotypical adults (N = 116 72 females). Participants underwent transcranial magnetic stimulation (TMS), electromyography (EMG), and electroencephalography (EEG) during the observation of videos of actors performing grasping actions in order to index IMR and mu suppression (in beta, lower alpha, and upper alpha bandwidths). A series of linear regressions revealed no associations between IMR and each of the mu suppression bandwidths. Supplementary Bayesian analyses provided further evidence in favor of the null (B
Publisher: The University of Sydney
Date: 2021
DOI: 10.25910/4XPF-3B74
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.BANDC.2016.08.001
Abstract: Previous research indicates that children with Developmental Coordination Disorder (DCD) show deficits performing online corrections, an issue exacerbated by adding inhibitory constraints however, cross-sectional data suggests that these deficits may reduce with age. Using a longitudinal design, the aim of the study presented here was to model the coupling that occurs between inhibitory systems and (predictive) online control in typically developing children (TDC) and in those with Developmental Coordination Disorder (DCD) over an extended period of time, using a framework of interactive specialization. We predicted that TDC would show a non-linear growth pattern, consistent with re-organisation in the coupling during the middle childhood period, while DCD would display a developmental lag. A group of 196 children (111 girls and 85 boys) aged between 6 and 12years participated in the study. Children were classified as DCD according to research criteria. Using a cohort sequential design, both TDC and DCD groups were ided into age cohorts. Predictive (online) control was defined operationally by performance on a Double-Jump Reaching Task (DJRT), which was assessed at 6-month intervals over two years (5 time points in total). Inhibitory control was examined using an anti-jump condition of the DJRT paradigm whereby children were instructed to touch a target location in the hemispace opposite a cued location. For the TDC group, model comparison using growth curve analysis revealed that a quadratic trend was the most appropriate fit with evidence of rapid improvement in anti-reach performance up until middle childhood (around 8-9years of age), followed by a more gradual rate of improvement into late childhood and early adolescence. This pattern was evident on both chronometric and kinematic measures. In contrast, for children with DCD, a linear function provided the best to fit on the key metrics, with a slower rate of improvement than controls. We conclude that children with DCD require a more extended period of development to effectively couple online motor control and executive systems when completing anti-reach movements, whereas TDC show rapid improvement in early and middle childhood. These group differences in growth curves are likely to reflect a maturational lag in the development of motor-cognitive networks in children with DCD.
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.JECP.2015.06.013
Abstract: We investigated the purported association between developmental changes in the efficiency of online reaching corrections and improved action representation. Younger children (6-7 years), older children (8-12 years), adolescents (13-17 years), and young adults (18-24 years) completed a double-step reaching paradigm and a motor imagery task. Results showed similar nonlinear performance improvements across both tasks, typified by substantial changes in efficiency after 6 or 7 years followed by incremental improvements. Regression showed that imagery ability significantly predicted reaching efficiency and that this association stayed constant across age. Findings provide the first empirical evidence that more efficient online control through development is predicted, partly, by improved action representation.
Publisher: Informa UK Limited
Date: 30-11-2022
Publisher: Informa UK Limited
Date: 02-2013
DOI: 10.1080/87565641.2012.718820
Abstract: The present study aimed to clarify whether a reduced ability to correct movements in-flight observed in children with developmental coordination disorder (DCD) reflects a developmental immaturity or deviance from the typical trajectory. Eighteen children with DCD (8-12 years), 18 age-matched controls, and 12 younger controls (5-7 years) completed a double-step reaching task. Compared to older controls, children with DCD and younger controls showed similarly prolonged reaching when the target unexpectedly shifted at movement onset and were equally slow to correct their reaching trajectory. These results suggest that impaired online control in DCD reflects developmental immaturity, possibly implicating the parietal-cerebellar cortices.
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.BANDC.2010.12.004
Abstract: In a recent study, children with movement clumsiness (or Developmental Coordination Disorder-DCD) were shown to have difficulties making rapid online corrections when reaching, demonstrated by slower and less accurate movements to double-step targets (Hyde & Wilson, 2011). These results suggest that children with DCD have difficulty using predictive estimates of limb position when making rapid adjustments to movement, in-flight. However, chronometric data alone does not provide strong evidence for this hypothesis: it remains unclear whether early (and rapid) control parameters or post-correction stages of the movement trajectory are affected. Thus, the overarching aim of this study was to conduct a kinematic analysis of double-step reaching in order to isolate the different control parameters that might explain the slower and less accurate double-step reaching performance of children with DCD. Participants were a new s le of 13 children with DCD aged between 8-12 years and 13 age-matched controls. Children were required to reach and touch one of three possible targets presented at the coordinates -20°, 0° and 20° on a 17 in. LCD touch-screen. For most trials (80%) the target remained stationary for the duration of movement (non-jump trials), while for the remainder (20%), the target jumped randomly to one of two peripheral locations at movement onset (jump trials). Consistent with earlier work, children with DCD were slower to initiate reaching compared to controls and showed longer MT and more errors on jump trials. Kinematic data showed that while the two groups did not differ on time to peak velocity or acceleration, children with DCD were slower to correct reach trajectory on jump trials. No group differences were observed on late kinematic markers, e.g., post-correction time. The pattern of results support and extend earlier work showing deficits in ROC in DCD. From a computational perspective, delayed corrections to the reach trajectory suggests some difficulty integrating information about the target perturbation with a predictive (or forward) estimate of limb position relative to the initial target. These conclusions are discussed, along with directions for future research.
Publisher: Informa UK Limited
Date: 02-01-2014
DOI: 10.1080/87565641.2013.855215
Abstract: We examined the influence of inhibitory load on online motor control in children. A s le of 129 school children was tested: younger, mid-age, and older children. Online control was assessed using a double-step perturbation paradigm across three trail types: non-jump, jump, and anti-jump. Results show that mid-aged children were able to implement online adjustments to jump trials as quickly as older children, but their performance on anti-jump trials regressed toward younger children. This suggests that rapid unfolding of executive systems during middle childhood may constrain the flexibility with which online control can be implemented, particularly when inhibitory demands are imposed.
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.RIDD.2014.10.013
Abstract: For children with Developmental Coordination Disorder (DCD), the real-time coupling between frontal executive function and online motor control has not been explored despite reported deficits in each domain. The aim of the present study was to investigate how children with DCD enlist online control under task constraints that compel the need for inhibitory control. A total of 129 school children were s led from mainstream primary schools. Forty-two children who met research criteria for DCD were compared with 87 typically developing controls on a modified double-jump reaching task. Children within each skill group were ided into three age bands: younger (6-7 years), mid-aged (8-9), and older (10-12). Online control was compared between groups as a function of trial type (non-jump, jump, anti-jump). Overall, results showed that while movement times were similar between skill groups under simple task constraints (non-jump), on perturbation (or jump) trials the DCD group were significantly slower than controls and corrected trajectories later. Critically, the DCD group was further disadvantaged by anti-jump trials where inhibitory control was required however, this effect reduced with age. While coupling online control and executive systems is not well developed in younger and mid-aged children, there is evidence of age-appropriate coupling in older children. Longitudinal data are needed to clarify this intriguing finding. The theoretical and applied implications of these results are discussed.
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.HUMOV.2014.03.013
Abstract: This study examined at what age children can engage in the hand rotation task (as a measure of motor imagery) whether engagement changes across development and the influence of age and motor skill on performance. Children were aged 5-12 years (N=101 52 girls), with no IQ or motor skill impairment. Less than 40% of 5-6 year olds completed the hand rotation with sufficient accuracy for further analysis, compared with 80% of 7-8 year olds, and 90% aged 9 and above. From age 7, either or both response time (RT) and accuracy conformed to the biomechanical constraints of corresponding physical movements. Although RT did not improve with age, accuracy did, with 11 year olds significantly more accurate than 7 and 8 year olds. Importantly, efficiency (RT/accuracy) improved with age and both age, in months, and motor skill level were significant predictors of efficiency, accounting for 35% and 8% of variability, respectively. Improvements in motor imagery ability during childhood are likely the result of increased neural efficiency, developing as the result of complex interactions between endogenous and exogenous factors. This highlights the need for a multidisciplinary approach to further our understanding of the emergence of motor imagery ability.
Publisher: SAGE Publications
Date: 04-12-2014
Abstract: This study aimed to investigate the integrity of on-line control of reaching in congenital spastic hemiplegia in light of disparate evidence. Twelve children with and without spastic hemiplegia (11-17 years old) completed a double-step reaching task requiring them to reach and touch a target that remained stationary for most trials (viz nonjump trial) but unexpectedly displaced laterally at movement onset for a minority of trials (20%: known as jump trials). Although children with spastic hemiplegia were generally slower than age-matched controls, they could account for target perturbation at age-appropriate levels shown by a lack of interaction effect on movement time and nonsignificant group difference for time to reach trajectory correction on jump trials. Our data suggest that at a group level, on-line control of reaching may be age-appropriate in spastic hemiplegia. However, our data also highlight the need to experimentally acknowledge the considerable heterogeneity of the spastic hemiplegia population when investigating motor cognition.
Publisher: Wiley
Date: 22-08-2023
DOI: 10.1002/HBM.26462
Abstract: It is well documented that attention‐deficit hyperactivity disorder (ADHD) often presents with co‐occurring motor difficulties. However, little is known about the biological mechanisms that explain compromised motor skills in approximately half of those with ADHD. To provide insight into the neurobiological basis of poor motor outcomes in ADHD, this study profiled the development of white matter organization within the cortico‐spinal tract (CST) in adolescents with ADHD with and without co‐occurring motor problems, as well as non‐ADHD control children with and without motor problems. Participants were 60 children aged 9–14 years, 27 with a history of ADHD and 33 controls. All underwent high‐angular resolution diffusion MRI data at up to three time points (115 in scans total). We screened for motor impairment in all participants at the third time point (≈14 years) using the Developmental Coordination Disorder Questionnaire (DCD‐Q). Following pre‐processing of diffusion MRI scans, fixel‐based analysis was performed, and the bilateral CST was delineated using TractSeg. Mean fiber density (FD) and fiber cross‐section (FC) were extracted for each tract at each time‐point. To investigate longitudinal trajectories of fiber development, linear mixed models were performed separately for the left and right CST, controlling for nuisance variables. To examine possible variations in fiber development between groups, we tested whether the inclusion of group and the interaction between age and group improved model fit. At ≈10 years, those with ADHD presented with lower FD within the bilateral CST relative to controls, irrespective of their prospective motor status. While these microstructural abnormalities persisted into adolescence for in iduals with ADHD and co‐occurring motor problems, they resolved for those with ADHD alone. Divergent maturational pathways of motor networks (i.e., the CST) may, at least partly, explain motor problems in iduals with ADHD.
Publisher: Wiley
Date: 09-12-2010
DOI: 10.1111/J.1365-2214.2010.01131.X
Abstract: Although there are a number of plausible accounts to explain movement clumsiness in children [or developmental coordination disorder (DCD)], the cause(s) of the disorder remain(s) an issue of debate. One aspect of motor control that is particularly important to the fluid expression of skill is rapid online control (ROC). Data on DCD have been conflicting. While some recent work using double-step reaching suggests no difficulty in online control, others suggest deficits (e.g. based on sequential pointing). To help resolve this debate, we suggest two things: use of recent neuro-computational models as a framework for investigating motor control in DCD, and more rigorous investigation of double-step reaching. Our working assumption here is that ROC is only viable through the seamless integration of predictive (or forward) models of movement and feedback-based mechanisms. The aim of this chronometric study was to explore ROC in children with DCD using a double-step reaching paradigm. We predicted slower online adjustments in DCD based on the argument that these children manifest a core difficulty in predictive control. Participants were a group of 17 children with DCD and 27 typically developing children aged between 7 and 12 years. Visual targets were presented on a 17-inch LCD touch screen, inclined to an angle of 15° from horizontal. The children were instructed to press each target as it appeared as quickly and accurately as possible. For 80% of the trials, the central target location remained unchanged for the duration of the movement (non-jump trials), while for the remaining 20% of trials, the target jumped at movement onset to one of the two peripheral locations (jump trials). Reaction time (RT), movement time (MT) and reaching errors were recorded. For both groups, RT did not vary according to trial condition, while children with DCD were slower to initiate movement. Further, the MT of children with DCD was prolonged to a far greater extent on jump trials relative to controls, with a large effect size. As well, children with DCD committed significantly more errors, notably a reduced ability to inhibit central responses on jump trials. Our findings help reconcile some disparate findings in the literature using similar tasks. The pattern of performance in children with DCD suggests impairment in the ability to make rapid online adjustments that are based on a predictive (or internal) model of the action. These results pave the way for future kinematic investigation.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2016
DOI: 10.1007/S12311-016-0788-7
Abstract: The cerebellum appears to play a key role in the development of internal rules that allow fast, predictive adjustments to novel stimuli. This is crucial for adaptive motor processes, such as those involved in walking, where cerebellar dysfunction has been found to increase variability in gait parameters. Motor adaptation is a process that results in a progressive reduction in errors as movements are adjusted to meet demands, and within the cerebellum, this seems to be localised primarily within the right hemisphere. To examine the role of the right cerebellar hemisphere in adaptive gait, cathodal transcranial direct current stimulation (tDCS) was administered to the right cerebellar hemisphere of 14 healthy adults in a randomised, double-blind, crossover study. Adaptation to a series of distinct spatial and temporal templates was assessed across tDCS condition via a pressure-sensitive gait mat (ProtoKinetics Zeno walkway), on which participants walked with an induced 'limp' at a non-preferred pace. Variability was assessed across key spatial-temporal gait parameters. It was hypothesised that cathodal tDCS to the right cerebellar hemisphere would disrupt adaptation to the templates, reflected in a failure to reduce variability following stimulation. In partial support, adaptation was disrupted following tDCS on one of the four spatial-temporal templates used. However, there was no evidence for general effects on either the spatial or temporal domain. This suggests, under specific conditions, a coupling of spatial and temporal processing in the right cerebellar hemisphere and highlights the potential importance of task complexity in cerebellar function.
Publisher: Wiley
Date: 29-03-2023
DOI: 10.1002/HBM.26288
Abstract: Attention deficit hyperactivity disorder (ADHD) is a prevalent childhood neurodevelopmental disorder. Given the profound brain changes that occur during childhood and adolescence, it is important to examine longitudinal changes of both functional and structural brain connectivity across development in ADHD. This study aimed to examine the development of functional and structural connectivity in children with ADHD compared to controls using graph metrics. One hundred and seventy five in iduals (91 children with ADHD and 84 non‐ADHD controls) participated in a longitudinal neuroimaging study with up to three waves. Graph metrics were derived from 370 resting state fMRI (197 Control, 173 ADHD) and 297 diffusion weighted imaging data (152 Control, 145 ADHD) acquired between the ages of 9 and 14. For functional connectivity, children with ADHD (compared to typically developing children) showed lower degree, local efficiency and betweenness centrality predominantly in parietal, temporal and visual cortices and higher degree, local efficiency and betweenness centrality in frontal, parietal, and temporal cortices. For structural connectivity, children with ADHD had lower local efficiency in parietal and temporal cortices and, higher degree and betweenness centrality in frontal, parietal and temporal cortices. Further, differential developmental trajectories of functional and structural connectivity for graph measures were observed in higher‐order cognitive and sensory regions. Our findings show that topology of functional and structural connectomes matures differently between typically developing controls and children with ADHD during childhood and adolescence. Specifically, functional and structural neural circuits associated with sensory and various higher order cognitive functions are altered in children with ADHD.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.RIDD.2015.07.027
Abstract: Recent evidence indicates that the ability to correct reaching movements in response to unexpected target changes (i.e., online control) is reduced in children with developmental coordination disorder (DCD). Recent computational modeling of human reaching suggests that these inefficiencies may result from difficulties generating and/or monitoring internal representations of movement. This study was the first to test this putative relationship empirically. We did so by investigating the degree to which the capacity to correct reaching mid-flight could be predicted by motor imagery (MI) proficiency in a s le of children with probable DCD (pDCD). Thirty-four children aged 8 to 12 years (17 children with pDCD and 17 age-matched controls) completed the hand rotation task, a well-validated measure of MI, and a double-step reaching task (DSRT), a protocol commonly adopted to infer one's capacity for correcting reaching online. As per previous research, children with pDCD demonstrated inefficiencies in their ability to generate internal action representations and correct their reaching online, demonstrated by inefficient hand rotation performance and slower correction to the reach trajectory following unexpected target perturbation during the DSRT compared to age-matched controls. Critically, hierarchical moderating regression demonstrated that even after general reaching ability was controlled for, MI efficiency was a significant predictor of reaching correction efficiency, a relationship that was constant across groups. Ours is the first study to provide direct pilot evidence in support of the view that a decreased capacity for online control of reaching typical of DCD may be associated with inefficiencies generating and/or using internal representations of action.
Publisher: Springer Science and Business Media LLC
Date: 25-05-2023
DOI: 10.1007/S13384-022-00539-Y
Abstract: Global policy development in schooling often looks to solutions that embrace technology and articulate a ‘what works’ approach to practice. This paper takes as a case study the Australian Government’s Through Growth to Achievement report on achieving school excellence. It analyses the report through the lens of ‘sublimes’, which provide insight into the way certain policy rhetoric can become reified. Through Growth to Achievement emphasises technological solutions which align with and reify an aesthetic notion of good teaching that draws on the ‘what works’ literature. This analysis argues that certain assumptions about technology, teacher practice and the ‘evidence’ for good policy are based on these reifications. A sublimes analysis makes these unspoken assumptions explicit and reveals the way they reinforce globalised policy approaches and foreclose others.
No related grants have been discovered for Christian Hyde.