Functional neuroimaging study of performances on a Go/No-go task in 6- to 7-year-old preterm children: Impact of intrauterine growth restriction ???

Children born preterm, and more specifically those with intrauterine growth restriction (IUGR), are prone to exhibit scholastic difficulties and behavioral problems later in development. Neuropsychological studies showed that their deficits in response inhibition and attention could be at the heart of these difficulties. Functional magnetic resonance imaging (fMRI) studies using a Go/No-go task in preterm adolescents and adults suggest their use of an alternative neuronal pathway to compensate for a possible delayed development. However, little is known about the impact of IUGR at a functional neural network level. This study used fMRI to explore brain regions activated during a Go/No-go task in 20 preterm children aged 6-7 years, 10 of which were born with IUGR. Results showed that preterm children without IUGR preferentially activated fronto-temporal regions including the inferior frontal cortex, region known to be involved in successful response inhibition. In contrast, IUGR preterm children exhibited greater activation in the putamen, in the medial frontal cortex and parietal regions, specifically involved in attention demanding tasks, some being part of the default-mode network. These findings suggest that IUGR preterm children use different brain regions and a more diffuse network to perform the task, which interfere with goal-directed activity and may reflect inefficient attentional control. The differences observed in IUGR preterm children might relate to their higher risk for neurodevelopmental and behavioral disorders

Altered Amygdala Development and Fear Processing in Prematurely Born Infants.

CONTEXT: Prematurely born children have a high risk of developmental and behavioral disabilities. Cerebral abnormalities at term age have been clearly linked with later behavior alterations, but existing studies did not focus on the amygdala. Moreover, studies of early amygdala development after premature birth in humans are scarce. OBJECTIVE: To compare amygdala volumes in very preterm infants at term equivalent age (TEA) and term born infants, and to relate premature infants' amygdala volumes with their performance on the Laboratory Temperament Assessment Battery (Lab-TAB) fear episode at 12 months. PARTICIPANTS: Eighty one infants born between 2008 and 2014 at the University Hospitals of Geneva and Lausanne, taking part in longitudinal and functional imaging studies, who had undergone a magnetic resonance imaging (MRI) scan at TEA enabling manual amygdala delineation. OUTCOMES: Amygdala volumes assessed by manual segmentation of MRI scans; volumes of cortical and subcortical gray matter, white matter and cerebrospinal fluid (CSF) automatically segmented in 66 infants; scores for the Lab-TAB fear episode for 42 premature infants at 12 months. RESULTS: Amygdala volumes were smaller in preterm infants at TEA than term infants (mean difference 138.03 mm(3), p < 0.001), and overall right amygdala volumes were larger than left amygdala volumes (mean difference 36.88 mm(3), p < 0.001). White matter volumes were significantly smaller (p < 0.001) and CSF volumes significantly larger (p < 0.001) in preterm than in term born infants, while cortical and subcortical gray matter volumes were not significantly different between groups. Amygdala volumes showed significant correlation with the intensity of the escape response to a fearsome toy (rs = 0.38, p = 0.013), and were larger in infants showing an escape response compared to the infants showing no escape response (mean difference 120.97 mm(3), p = 0.005). Amygdala volumes were not significantly correlated with the intensity of facial fear, distress vocalizations, bodily fear and positive motor activity in the fear episode. CONCLUSION: Our results indicate that premature birth is associated with a reduction in amygdala volumes and white matter volumes at TEA, suggesting that altered amygdala development might be linked to alterations in white matter connectivity reported in premature infants. Moreover, our data suggests that such alterations might affect infants' fear-processing capabilities

Structural Brain Connectivity in School-Age Preterm Infants Provides Evidence for Impaired Networks Relevant for Higher Order Cognitive Skills and Social Cognition.

Extreme prematurity and pregnancy conditions leading to intrauterine growth restriction (IUGR) affect thousands of newborns every year and increase their risk for poor higher order cognitive and social skills at school age. However, little is known about the brain structural basis of these disabilities. To compare the structural integrity of neural circuits between prematurely born controls and children born extreme preterm (EP) or with IUGR at school age, long-ranging and short-ranging connections were noninvasively mapped across cortical hemispheres by connection matrices derived from diffusion tensor tractography. Brain connectivity was modeled along fiber bundles connecting 83 brain regions by a weighted characterization of structural connectivity (SC). EP and IUGR subjects, when compared with controls, had decreased fractional anisotropy-weighted SC (FAw-SC) of cortico-basal ganglia-thalamo-cortical loop connections while cortico-cortical association connections showed both decreased and increased FAw-SC. FAw-SC strength of these connections was associated with poorer socio-cognitive performance in both EP and IUGR children

An investigation of verbal short-term memory and phonological processing in four children with Williams syndrome

Although phonological processing is generally considered to be a proficiency in Williams syndrome (WS), there are very few studies which have extensively explored phonological processing abilities in WS. In this study, we re-assessed phonological processing in WS by exploring verbal STM and phonological awareness abilities in 4 children with WS (CA: 10-12 years) and two control groups, one matched for chronological age (CA) and the other matched for verbal mental age (VA). Our results confirm and extend previous claims of preserved phonological STM in WS by showing specifically preserved STM performance for non-words, compared to both VA and CA control groups. However, we observed that this was the case only for non-words where support of phonological and lexico-semantic knowledge was minimized, with reduced phonological and lexico-semantic effects on STM performance. Furthermore, a more direct assessment of phonological processing abilities through phonological awareness tasks showed impaired performance for the 4 WS children. Our data confirm that STM for non-words represents a real strength in. WS but they do not support previous assumptions of a more general preservation of phonological processing abilities in WS. Implications for impaired and preserved cognitive processes underlying verbal STM and phonological awareness abilities in WS are discussed

How Flexible is the Use of Egocentric Versus Allocentric Frame of Reference in the Williams Syndrome Population?

Abstract Objective This study examined the spontaneous use of allocentric and egocentric frames of reference and their flexible use as a function of instructions. Method The computerized spatial reference task created by Heiz and Barisnikov (2015) was used. Participants had to choose a frame of reference according to three types of instructions: spontaneous, allocentric and egocentric. The performances of 16 Williams Syndrome participants between 10 and 41 years were compared to those of two control groups (chronological age and non-verbal intellectual ability). Results The majority of Williams Syndrome participants did not show a preference for a particular frame of reference. When explicitly inviting participants to use an allocentric frame of reference, all three groups showed an increased use of the allocentric frame of reference. At the same time, an important heterogeneity of type of frame of reference used by Williams Syndrome participants was observed. Conclusion Results demonstrate that despite difficulties in the spontaneous use of allocentric and egocentric frames of reference, some Williams Syndrome participants show flexibility in the use of an allocentric frame of reference when an explicit instruction is provided

Development of the ability to inhibit a prepotent response: influence of working memory and processing speed.

This study aimed to examine developmental trends in response inhibition during childhood and to control for possible developmental influence of other basic cognitive processes (such as working memory and processing speed). In addition, we explored the relationships between response inhibition, working memory, and processing speed, as they are thought to be integral to cognitive control. Therefore, we assessed these three cognitive abilities in 159 children aged from 5 to 12. Results showed an improvement in response inhibition ability from 5 to 10 years of age. This improvement remained significant after controlling for the influence of working memory and processing speed. Furthermore, the developmental relationships showed an early differentiation between response inhibition, working memory, and processing speed. Thus, these processes were independent and need to be treated as such in further studies

Social reasoning abilities in preterm and full-term children aged 5-7years.

Literature has evidenced behavioral and socio-emotional problems in preterm children, as well as long-term difficulties to establish and maintain social relationships in preterm population. Several studies have shown relations between behavior and social reasoning abilities in typically developing children and adults. The present study aimed to investigate the social understanding and social reasoning abilities in preterm children aged between 5 and 7years in comparison to their full-term peers. A social resolution task (SRT) was used to assess abilities to judge, identify and reason about others' behavior in relation to conventional and moral rules knowledge. 102 preterm children and 88 full-term children were included in the study. Compared with their full-term peers, preterm children exhibited difficulties to understand and reason about inappropriate social behavior, particularly for situations related to the transgression of conventional rules. They used more irrelevant information and exhibited less social awareness when reasoning about the transgression of social rules. The only significant predictor for global SRT and social reasoning scores was the mental processing composite of the K-ABC, but the part of the variance of the SRT that could be explained by the general cognitive abilities was relatively small. Preterm children demonstrated poorer social knowledge and social reasoning abilities compared with full-term children at early school age. Improving such abilities may reduce behavioral difficulties and peer relationship problems often described in the preterm population. These findings emphasize the need to early identify children at risk for impaired social development