Analyzing the association between functional connectivity of the brain and intellectual performance

Abstract

Measurements of functional connectivity support the hypothesis that the brain is composed of distinct networks with anatomically separated nodes but common functionality. A few studies have suggested that intellectual performance may be associated with greater functional connectivity in the fronto-parietal network and enhanced global efficiency. In this fMRI study, we performed an exploratory analysis of the relationship between the brain's functional connectivity and intelligence scores derived from the Portuguese language version of the Wechsler Adult Intelligence Scale (WAIS-III) in a sample of 29 people, born and raised in Brazil. We examined functional connectivity between 82 regions, including graph theoretic properties of the overall network. Some previous findings were extended to the Portuguese-speaking population, specifically the presence of small-world organization of the brain and relationships of intelligence with connectivity of frontal, pre-central, parietal, occipital, fusiform and supramarginal gyrus, and caudate nucleus. Verbal comprehension was associated with global network efficiency, a new finding.

Characterisation of Functional Brain Networks underlying Cognitive Reasoning and Intelligence

“…Speaking to this directly, van den Heuvel and colleagues (2009) found a strong positive relationship between functional network global efficiency and intelligence. This finding has been replicated for different behavioural measures of intelligence (e.g., Pamplona et al, 2015), as well as across imaging techniques (Langer et al, 2011).…”

“…As a striking example, in a follow-up study using the same data reported above (Song et al, 2008), Song and colleagues (2009) found that several connections within the default-mode network also correlated with intelligence, suggesting that the existing 'FPNcentric' literature may reflect biased analysis decisions, such as region of interest choice. In line with this, a number of studies have related individual differences in intelligence to resting-state connectivity of the default-mode network and cingulo-opercular network (Pamplona et al, 2015;Santarnecchi et al, 2015;Wang et al, 2011;Yuan et al, 2012). While the CON is often seen as a critical counterpart to the FPN (Seeley et al, 2007), the DMN is considered antagonistic to it .…”

“…Attempts to test this prediction, however, have so far produced inconclusive findings. For example, individual differences in intelligence have been related to changes in resting-state connectivity in neural networks broadly involved in self-referential mental activity (default-mode network), attentional control processes (dorsal attention network) and task-set maintenance (cingulo-opercular network; Pamplona et al, 2015;Santarnecchi et al, 2015;Song et al, 2009;Wang et al, 2011;Yuan et al, 2012). …”

Intelligence neurocircuitry: cortical and subcortical structures

“…The COMT (catechol-o-methyl transferase) polymorphisms relate directly and strongly with IQ scores. The polymorphic gene that leads to a Val166Met mutation in the protein alters the activity of brain-derived neurotrophic factor (BDNF), interfering with cognitive functions (DUNCAN, 2013;OHTANI, NESTOR, BOUIX et al, 2014;PAMPLONA, SANTOS NETO, ROSSET et al, 2015;KOTEN JUNIOR, WOOD, HAGOORT et al, 2009;DEARY, PENKE and JOHNSON, 2010).…”

“…The model of frontoparietal integration (P-FIT model) match the neuroimaging findings, but many functional studies, according to genre and age, will probably modify the intelligence circuits accepted nowadays. Future pharmacologic interventions will be at hand to stimulate or to inhibit specific neurocircuits involved with cognition, open the way to an effective therapy to learning disturbances and neuropsychiatric diseases (GRAY and THOMPSON, 2004;LUDERS, NARR, THONPSOM, 2009;RHEIN, MÜHLE, RICHTER-SCHMIDINGER et al, 2014;PAMPLONA, SANTOS NETO, ROSSET et al, 2015;GLASCHER, TRANEL, PAUL et al, 2009). …”