Relationships between IQ and Regional Cortical Gray Matter Thickness in Healthy Adults

Laboratory of Neuro Imaging, Department of Neurology, Geffen School of Medicine at the University of California, Los Angeles (UCLA), Los Angeles, CA 90095-7334, USA.
Cerebral Cortex (Impact Factor: 8.67). 10/2007; 17(9):2163-71. DOI: 10.1093/cercor/bhl125
Source: PubMed


Prior studies show positive correlations between full-scale intelligence quotient (FSIQ) and cerebral gray matter measures. Few imaging studies have addressed whether general intelligence is related to regional variations in brain tissue and the associated influences of sex. Cortical thickness may more closely reflect cytoarchitectural characteristics than gray matter density or volume estimates. To identify possible localized relationships, we examined FSIQ associations with cortical thickness at high spatial resolution across the cortex in healthy young adult (age 17-44 years) men (n = 30) and women (n = 35). Positive relationships were found between FSIQ and intracranial gray and white matter but not cerebrospinal fluid volumes. Significant associations with cortical thickness were evident bilaterally in prefrontal (Brodmann's areas [BAs] 10/11, 47) and posterior temporal cortices (BA 36/37) and proximal regions. Sex influenced regional relationships; women showed correlations in prefrontal and temporal association cortices, whereas men exhibited correlations primarily in temporal-occipital association cortices. In healthy adults, greater intelligence is associated with larger intracranial gray matter and to a lesser extent with white matter. Variations in prefrontal and posterior temporal cortical thickness are particularly linked with intellectual ability. Sex moderates regional relationships that may index dimorphisms in cognitive abilities, overall processing strategies, or differences in structural organization.

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    • "These structural abnormalities correlate with ICDs severity and are independent from cognitive deficits which characterized ICDþ patients as already reported in previous studies[3,4]. Corticometric abnormalities are manifested in health[9], normal aging[10]and in many addiction disorders, like in cocaine[11]and heroin users[12], or online gamers[13], revealing a thicker pattern in cortical areas linked to impulsivity and behaviors inhibition . Moreover, corticometry has provided further insights in the pathophysiology of psychiatric diseases, like obsessive-compulsive disorder patients[14], showing a thicker cortex within orbitofrontal and cingulate cortices when compared to HCs. "
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    ABSTRACT: Introduction: To investigate gray matter (GM) and cortical thickness (CTh) changes in patients with Parkinson's disease (PD) with and without Impulse Control Disorders (ICDs). Methods: Fifteen patients with PD with ICDs (ICD+), 15 patients with PD without ICDs (ICD-) and 24 age and sex-matched healthy controls (HCs) were enrolled in the study. Patients were screened for ICDs by the Minnesota Impulsive Disorders Interview (MIDI) and underwent an extensive neuropsychological evaluation. Whole brain structural imaging was performed on a 3T GE MR scanner. Surface-based investigation of CTh was carried out by using Freesurfer Software. We also used voxel-based morphometry to investigate the pattern of GM atrophy. Results: The voxel-wise analysis of the regional differences in CTh revealed that ICD+ patients showed a statistically significant (p<0.01 FDR) thicker cortex when compared to both ICD- patients and HCs in the anterior cingulate (ACC) and orbitofrontal (OFC) cortices. Moreover, cortical thickness abnormalities were positively correlated with ICD severity (p<0.05 FDR). VBM data did not reveal any statistically significant differences in local GM. Conclusions: Our results demonstrate that ICD+ patients have an increased CTh in limbic regions when compared with ICD- patients at the same disease stage and with an equal daily levodopa equivalent dose. These corticometric changes may play a role in the lack of inhibition of compulsive behaviors. The presence of such structural abnormalities may result from a synergistic effect of dopaminergic therapy in patients with a pre-existing vulnerability to develop an abnormal behavioral response to external stimuli.
    Full-text · Article · Oct 2015 · Parkinsonism & Related Disorders
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    • "Distinct regions of the cerebral cortex show consistent associations with general intellectual ability, as shown in brain imaging studies measuring brain structure, and activity (Haier et al., 2004; Gray and Thompson, 2004; Jung and Haier, 2007; Narr et al., 2007; Colom et al., 2009; Barbey et al., 2012; Schnack et al., 2014). These regions include early information processing areas of the temporal (fusiform gyrus, Wernicke's area) and occipital lobes (extrastriate cortex) as well as higher associative processing areas of the parietal (supramarginal gyrus, angular gyrus and superior parietal gyrus) and frontal lobes (dorsolateral prefrontal cortex, inferior frontal gyrus and orbitofrontal cortex). "
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    • "e l s e v i e r . c o m / l o c a t e / y n i m g (Narr et al., 2007) and white matter tracts (Van Beek et al., 2014). A brain network perspective provides a quantitative model for elucidating the association between the efficiency of brain networks and intelligence (Cole et al., 2012; van den Heuvel et al., 2009). "

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