A Meta-Analysis of Executive Functions in Frontal Cortex: Comparing Healthy and Neuropsychiatric Groups

Abstract

BackgroundThe neural architecture of executive functions remains a topic of considerable clinical and academic interest in the clinical neurosciences, given its strength as a transdiagnostic predictor of adaptive functioning with high heritability. In recent years, meta-analyses have shown a consistent relationship between prefrontal cortex size and executive functioning task performance in healthy adults and lesion patients, with increases in measures of cortical size (i.e., volume or thickness) associated with better executive functioning performance. There is a gap in meta-analytic literature assessing these relationships in neuropsychiatric populations, their effects relative to healthy controls, and differential contributions of brains regions and neuropsychological paradigms.MethodsWe conducted a meta-analysis of published studies (k =30) that assessed the relationship between executive functions and frontal regions in vivo (N = 1935) for both healthy (20 samples) and neuropsychiatric (21 samples) adults. Random effects modeling was used to calculate mean effect sizes and CIs.ResultsLarger volumes and thickness were associated with better executive functioning in both healthy (r =.35, 95% CI =.29 -.39) and neuropsychiatric populations (r =.47, 95% CI =.40 -.51), with the effect size for neuropsychiatric populations being significantly larger compared to healthy controls. While there was variability between tasks, there were no significant differences in effect size between neuropsychological paradigms or brain region classification.ConclusionsThese results indicate the relationship between healthy adult performance on neuropsychological testing is less associated with cortical size compared to neuropsychiatric adults.

Components of executive function model regional prefrontal volumes.

“…Although NKI-RS is demographically and socioeconomically generalizable to the United States, the contribution of this study to clinical neuropsychology is predicated on such brain–behavior relationships operating in both clinical and nonclinical samples. In accordance with the validation of the D-KEFS in lesion studies, the modest effect sizes for EF and frontal volume found in this study are expected to be stronger in neuropsychiatric populations (Waters, Swenson et al, 2018). It is possible that additional EF–frontal associations were not detectable in this sample of community-dwelling adults (Type II error).…”

“…dance with the validation of the D-KEFS in lesion studies, the modest effect sizes for EF and frontal volume found in this study are expected to be stronger in neuropsychiatric populations (Waters, Swenson et al, 2018). It is possible that additional EF-frontal associations were not detectable in this sample of communitydwelling adults (Type II error).…”

“…Like many traditional neuropsychological tests of EF, the D-KEFS has been validated with lesion studies that show marked deficits for both individual aspects of EF (Barbey et al, 2012; Strong, Tiesma, & Donders, 2011; Yochim, Baldo, Nelson, & Delis, 2007) and a common EF factor (Gansler, Huey, Pan, Wasserman, & Grafman, 2017). There is substantial literature showing that EF is associated with a diverse network of frontal regions in both neuropsychiatric (Nowrangi, Lyketsos, Rao, & Munro, 2014; Waters, Swenson, & Gansler, 2018) and healthy (e.g., Adólfsdóttir et al, 2014; Elderkin-Thompson, Ballmaier, Hellemann, Pham, & Kumar, 2008; Ruscheweyh et al, 2013; Yuan & Raz, 2014) populations. Executive deficits observed in patients may be the result of multiple attentional circuits connecting both frontal and posterior regions that are adaptive to multiple contexts, some of which support a more focal relationship between individual regions and diverse EF functions (Stuss, 2011; Stuss & Alexander, 2007).…”

Components of Executive Function Predict Regional Prefrontal Volumes

“…Although NKI-RS is demographically and socioeconomically generalizable to the US, the contribution of this study to clinical neuropsychology is predicated on such brainbehavior relationships operating in both clinical and non-clinical samples. In accordance with the validation of the D-KEFS in lesion studies, the modest effect sizes for EF and frontal volume found in this study are expected to be stronger in neuropsychiatric populations (Waters, Swenson, & Gansler, 2018).…”