Overlapping and dissociable brain activations for fluid intelligence and executive functions

https://doi.org/10.3758/s13415-021-00870-4

Abstract

Cognitive enhancement interventions aimed at boosting human fluid intelligence (gf) have targeted executive functions (EFs), such as updating, inhibition, and switching, in the context of transfer-inducing cognitive training. However, even though the link between EFs and gf has been demonstrated at the psychometric level, their neurofunctional overlap has not been quantitatively investigated. Identifying whether and how EFs and gf might share neural activation patterns could provide important insights into the overall hierarchical organization of human higher-order cognition, as well as suggest specific targets for interventions aimed at maximizing cognitive transfer. We present the results of a quantitative meta-analysis of the available fMRI and PET literature on EFs and gf in humans, showing the similarity between gf and (i) the overall global EF network, as well as (ii) specific maps for updating, switching, and inhibition. Results highlight a higher degree of similarity between gf and updating (80% overlap) compared with gf and inhibition (34%), and gf and switching (17%). Moreover, three brain regions activated for both gf and each of the three EFs also were identified, located in the left middle frontal gyrus, left inferior parietal lobule, and anterior cingulate cortex. Finally, resting-state functional connectivity analysis on two independent fMRI datasets showed the preferential behavioural correlation and anatomical overlap between updating and gf. These findings confirm a close link between gf and EFs, with implications for brain stimulation and cognitive training interventions.

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Kevin S. McGrew, PhD
Educational & School Psychologist
Director
Institute for Applied Psychometrics (IAP)
https://www.themindhub.com
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Is there a “g-neuron”? Establishing a systematic link between general intelligence (g) and the von Economo neuron - ScienceDirect

 Is there a "g-neuron"? Establishing a systematic link between general intelligence (g) and the von Economo neuron - ScienceDirect 
https://www.sciencedirect.com/science/article/abs/pii/S0160289621000246?via%3Dihub

Abstract
The construct of general intelligence (g) is one of psychology's most replicated and predictively useful constructs. Although research indicates that g is a highly heritable trait, deeply rooted in brain physiology, to date neither a strong biological correlate nor a comprehensive explanatory model involving neuronal mechanisms have been established. In this article I aim to do so by hypothesising that the von Economo neuron (VEN), a unique nerve cell thus far implicated in social cognitionand interoception, may in fact represent a central biological constituent of g. After presenting supportive evidence from neuroscience, psychiatry/neurology, clinical gerontology, and comparative psychology, an integrated reductionist framework is outlined, which reaches from the level of cognitive theory to the level of single neurons. Based thereon, it is concluded that the VENs might contribute to individual differences in g by rapidly inducing the coherence of neuronal oscillations within a functionally invariant parieto-frontal network underlying higher-order cognition, thereby facilitating mental efficiency.

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Kevin S. McGrew, PhD
Educational & School Psychologist
Director
Institute for Applied Psychometrics (IAP)
https://www.themindhub.com
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Estimates of brain age for gray matter and white matter in younger and older adults: insights into human intelligence - ScienceDirect

 Estimates of brain age for gray matter and white matter in younger and older adults: insights into human intelligence - ScienceDirect 
https://www.sciencedirect.com/science/article/abs/pii/S0006899321002882

Abstract

Aging entails a multifaceted complex of changes in macro- and micro-structural properties of human brain gray matter (GM) and white matter (WM) tissues, as well as in intellectual abilities. To better capture tissue-specific brain aging, we combined volumetric and diffusivity properties to derive subject-specific age scores for each tissue. We compared age-related variance between WM and GM age scores in younger and older adults and tested whether tissue-specific age scores could explain different effects of aging on fluid (Gf) and crystalized (Gc) intelligence in younger and older adults. Chronological age was strongly associated with GM (R² = 0.73) and WM (R² = 0.57) age scores. The GM age score accounted for significantly more variance in chronological age in younger relative to older adults (p < 0.001), whereas the WM age score accounted for significantly more variance in chronological age in older compared to younger adults (p < 0.025). Consistent with existing literature, younger adults outperformed older adults in Gf while older adults outperformed younger adults in Gc. The GM age score was negatively associated with Gf in younger adults (p < 0.02), whereas the WM age score was negatively associated with Gc in older adults (p< 0.02). Our results provide evidence for differences in the effects of age on GM and WM in younger versus older adults that may contribute to age-related differences in Gf and Gc.

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Kevin S. McGrew, PhD
Educational & School Psychologist
Director
Institute for Applied Psychometrics (IAP)
https://www.themindhub.com
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Does reasoning training improve fluid reasoning and academic achievement for children and adolescents? A systematic review - ScienceDirect

 Does reasoning training improve fluid reasoning and academic achievement for children and adolescents? A systematic review - ScienceDirect 
https://www.sciencedirect.com/science/article/abs/pii/S2211949321000053

Abstract

BACKGROUND
Studies of children and adolescents suggest that reasoning training may improve both reasoning and academic achievement, but evidence and systematic evaluation of this research is limited. Accordingly, this paper provides a systematic review of the literature on reasoning training in order to describe current methods and evaluate their efficacy.

METHOD
A systematic search identified eleven articles—published between 1996 and 2016—that reported findings from thirteen separate studies of reasoning training effects on fluid reasoning (Gf) and academic achievement in children and adolescents. Specific Gf outcomes examined were analogical, deductive, inductive, nonverbal, and/or relational reasoning ability. Specific academic achievement outcomes examined were math and reading achievement. This paper reviewed studies utilizing both computerized and non-computerized methods of Gftraining.

FINDINGS
Findings from the review show that reasoning training improves Gf (near transfer effects). Although less conclusive, when considered on balance, evidence suggests that reasoning training also improves academic achievement (far transfer effects).

CONCLUSIONS
Research is needed to parameterize the effects of Gftraining on academic achievement, and in particular to identify moderators of training efficacy on academic outcomes. Limitations and directions for future research are discussed.

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Kevin S. McGrew, PhD
Educational & School Psychologist
Director
Institute for Applied Psychometrics (IAP)
https://www.themindhub.com
******************************************

Integrated Intelligence from Distributed Brain Activity: Trends in Cognitive Sciences

More on the central role of central control (AC-Gsm) in general intelligence.

"Earlier we noted positive manifold, the finding of ubiquitous positive correlations between different cognitive tests, and Spearman's original proposal that some general or g factor contributes to success in any cognitive activity [11,12]. One simple interpretation is that g reflects the attentional integration functions of the MD system and, in agreement with Spearman's hypothesis, we suggest that MD functions contribute very broadly to effective cognition. At the same time, it seems likely that the full explanation for positive manifold is more nuanced, with multiple contributory factors [39,58]."


Integrated Intelligence from Distributed Brain Activity: Trends in Cognitive Sciences 

tinyurl.com/ykbwklk5