Presence or absence of a prefrontal sulcus is linked to reasoning performance during child development

Abstract

The relationship between structural variability in late-developing association cortices like the lateral prefrontal cortex (LPFC) and the development of higher-order cognitive skills is not well understood. Recent findings show that the morphology of LPFC sulci predicts reasoning performance; this work led to the observation of substantial individual variability in the morphology of one of these sulci, the para-intermediate frontal sulcus (pimfs). Here, we sought to characterize this variability and assess its behavioral significance. To this end, we identified the pimfs in a developmental cohort of 72 participants, ages 6–18. Subsequent analyses revealed that the presence or absence of the ventral component of the pimfs was associated with reasoning, even when controlling for age. This finding shows that the cortex lining the banks of sulci can support the development of complex cognitive abilities and highlights the importance of considering individual differences in local morphology when exploring the neurodevelopmental basis of cognition.

Sulcal variability in anterior lateral prefrontal cortex contributes to variability in reasoning performance among young adults

“…While this effect was significant, it was not as large as that observed for the reasoning test (ΔAIC (working memory - reasoning) = 142.23). By contrast, left pimfs-v presence was not related to processing speed test performance (t(69) = -0.24, p = 0.81, d = -0.07 ; figure 2 d ), a finding suggesting some degree of specificity in this brain–behavior relation and consistent with previous anatomical-cognitive findings in our pediatric cohort [23,24].…”

“…There was no hemispheric asymmetry in incidence rates ( p = 0.66; figure 1 ), and when only one pimfs component was present, it was equally likely to be a dorsal or ventral component (χ 2 < 2, p > .15 in both hemispheres; figure 1 ). These incidence rates were similar to those observed in children and adolescents [24], which was anticipated given that sulci are formed during gestation [3,12,55,65,66].…”

“…A combination of previous findings [23–25] further motivated the present study, showing that a sulcus in anterior LPFC (ventral para-intermediate frontal sulcus, pimfs-v) was variably present in children and adolescents [23,24] and markedly rare in chimpanzees [25]. Further, the presence of left hemisphere pimfs-v in a sample of 6-18-year-olds was associated with higher reasoning scores [24]. Building on these previous results in the present study, we show that the sulcal patterning of the pimfs and the relationship between the presence/absence of the pimfs-v and reasoning is a reliable and enduring individual difference generalizing to an adult sample (ages 22-36).…”

“…As the pimfs is variably present among young adults, we statistically tested whether this variability was related to reasoning performance, as previously found for children and adolescents [24]. Reasoning performance was quantified as scores on the Penn Progressive Matrices Test from the NIH Toolbox [34], a relational reasoning task similar to the WISC-IV Matrix Reasoning task used previously [23,24,40]. The presence of two pimfs components in the left hemisphere was associated with 21% better reasoning performance relative to either one or none (t(69) = 2.54, p = 0.01, d = 0.67).…”

“…To date, relationships between the presence/absence of variable sulci and cognition have been most widely explored in the anterior cingulate cortex (ACC) [12]; here, we focus on variations in the folding of the lateral prefrontal cortex (LPFC), a highly expanded region crucial for higher-level functions such as abstract reasoning [16–22]. A combination of previous findings [23–25] further motivated the present study, showing that a sulcus in anterior LPFC (ventral para-intermediate frontal sulcus, pimfs-v) was variably present in children and adolescents [23,24] and markedly rare in chimpanzees [25]. Further, the presence of left hemisphere pimfs-v in a sample of 6-18-year-olds was associated with higher reasoning scores [24].…”