Processing of intentional and automatic number magnitudes in children born prematurely: evidence from fMRI

Abstract

This study examined the neural correlates of intentional and automatic number processing (indexed by number comparison and physical Stroop task, respectively) in 6- and 7-year-old children born prematurely. Behavioral results revealed significant numerical distance and size congruity effects. Imaging results disclosed (1) largely overlapping fronto-parietal activation for intentional and automatic number processing, (2) a frontal to parietal shift of activation upon considering the risk factors gestational age and birth weight, and (3) a task-specific link between math proficiency and functional magnetic resonance imaging (fMRI) signal within distinct regions of the parietal lobes-indicating commonalities but also specificities of intentional and automatic number processing.

FIGURE 1

Panel A (blue) shows activation in the physical Stroop task, while Panel B (yellow) depicts cortical areas associated with the processing of the number processing task. As can be seen, the fronto-parietal areas observed were nearly identical. Only in the number comparison task, additional activation in the inferior frontal gyrus is observed. Panel C depicts the conjunction over the two experimental tasks (given in red).

FIGURE 2

Panel A depicts activation associated with the covariate gestational age. While a lower gestational age was associated with bilateral inferior frontal activation (green), a larger gestational age was associated with predominant activation in bilateral parietal regions (red) as well as bilateral superior temporal areas. Panel B shows primarily extended parietal activation associated with a larger birth weight comprising left intraparietal sulcus (IPS), bilateral angular gyrus, precuneus, postcentral gyrus. Panel C depicts activation associated with lower general cognitive ability (as indexed by estimated intelligence). The picture is dominated by frontal activation in the supplementary motor area, bileratal inferior frontal and left middle frontal gyrus but also extends into parietal regions such as the IPS. Panel D depicts activation associated with math proficiency (as indexed by TEDI-MATH scores). While higher math proficiency was associated with left inferior frontal activation (red), lower math proficiency was found to activate the fronto-parietal network (green), including bilateral parietal regions, bilateral superior temporal areas, right inferior frontal and bilateral middle frontal cortices.

FIGURE 3

Panel A depicts the activation in the left superior parietal lobule on the cytoarchitectonic brain maps, while Panel B shows the activation center in the left intraparietal sulcus (IPS). The bar charts below the activation figures depict the corresponding beta estimates for the respective brain region. Note that differential effects can be found in these regions for physical and numerical magnitude processing: while the physical Stroop task elicited larger activation in the left superior parietal lobule, the number comparison task led to stronger activations of the IPS. Note. BW = birth weight; GCA = general cognitive abilities; TM = TEDI-MATH; EOI = effects of interest.