Genetic influences on prefrontal activation during a verbal fluency task in children: A twin study using near‐infrared spectroscopy

Abstract

ObjectiveThe genetic and environmental influences on prefrontal function in childhood are underinvestigated due to the difficulty of measuring prefrontal function in young subjects, for which near‐infrared spectroscopy (NIRS) is a suitable functional neuroimaging technique that facilitates the easy and noninvasive measurement of blood oxygenation in the superficial cerebral cortices.MethodUsing a two‐channel NIRS arrangement, we measured changes in bilateral prefrontal blood oxygenation during a category version of the verbal fluency task (VFT) in 27 monozygotic twin pairs and 12 same‐sex dizygotic twin pairs ages 5–17 years. We also assessed the participant's full‐scale intelligence quotient (FIQ) and retrieved parental socioeconomic status (SES). Classical structured equation modeling was used to estimate the heritability.ResultsThe heritability of VFT‐related brain activation was estimated to be 44% and 37% in the right and left prefrontal regions, respectively. We also identified a significant genetic contribution (74%) to FIQ, but did not to VFT task performance. Parental SES was not correlated with FIQ, task performance, or task‐related prefrontal activation.ConclusionsThis finding provides further evidence that variance in prefrontal function has a genetic component since childhood and highlights brain function, as measured by NIRS, as a promising candidate for endophenotyping neurodevelopmental disorders.

Cognition and emotion: Family member similarity and intergenerational transmission.

“…fNIRS has better temporal resolution than fMRI, better spatial resolution than EEG, can be used in naturalistic environments, is less susceptible to artifacts from movement, and can directly measure changes in blood oxygenation levels related to neural activation; however, it is limited to brain activity changes on and near the surface of the brain (Tak & Ye, 2014;Westgarth et al, 2021). fNIRS has only just begun to be included in family studies (e.g., Ohi et al, 2017;Sakakibara et al, 2018); it will be some time before the field has multiple estimates of familial resemblance for fNIRS indicators of cognitive regulation of emotion.…”

Environmental and genetic influences on self-directed executive functioning in childhood

“…Despite its frequent use in both clinical and experimental settings, genetically-informed studies of verbal fluency have focused exclusively on total word production, rather than more specific switching indices. Multiple adult studies have shown both genetic and environmental contributions to performance on verbal fluency tasks (Hayiou-Thomas et al, 2006;Kavé et al, 2013;Kovas et al, 2005;Owens et al, 2011;Swan & Carmelli, 2002) and find that by middle age, approximately 45% of the variance verbal fluency performance is explained by genetic contributions (Gustavson et al, 2018;Jones-Odeh et al, 2016;Sakakibara et al, 2018). Only one study has focused on a developmental sample (Kavé et al, 2013), and that work was limited to 4-year-olds, who show only nascent executive abilities.…”