A frontoparietal network may be relevant for intelligence, but also for working memory.37 A study by Gray et al38 tested whether fluid or reasoning ability (Gf) was mediated by neural mechanisms supporting working memory. Sixty participants performed verbal and nonverbal working memory tasks. They had to indicate if a Selleckchem Proteasome inhibitor current item matched the item they saw 3 items previously (3-back). Brain activity was measured by event-related functional magnetic resonance imaging (fMRI). The demand for working memory varied across trials. Results showed that: (i) participants scoring higher on the Progressive Matrices Inhibitors,research,lifescience,medical Test (a measure related to fluid g – Gf) were more accurate in the 3-back task; and (ii) only lateral prefrontal

Inhibitors,research,lifescience,medical and parietal regions mediated the correlation between

Gf and 3-back performance. These fMRI results are consistent with the voxel-based morphometry (VBM) study reported by Colom et al (N = 48).39 In agreement with the well established fact that the g factor and working memory capacity are very highly correlated,40-45 these researchers predicted that g and working memory would share significant Inhibitors,research,lifescience,medical common neural networks. Therefore, using a VBM approach they quantified the overlap in brain areas where regional gray matter was correlated with measures of general intelligence and working memory, finding a common neuroanatomic framework supported by frontal gray matter regions belonging to BA 10 and by the right inferior parietal lobule (BA 40). Of note, this study also showed: (i) more gray matter recruitment for the more cognitively complex tasks (= more highly g loaded); and (ii) the complex span task (backward digit span) showed more gray matter overlap with the general factor of intelligence Inhibitors,research,lifescience,medical than the simple span task (forward digit span, (Figure 5). These results were interpreted after the theory proposed by Cowan,46 namely that parietal regions support “capacity limitations,” whereas frontal areas underlie the “control of attention.” Figure 5. Overlap of correlations between gray matter and Inhibitors,research,lifescience,medical g (conjunction of block design and vocabulary)

and gray matter and forward (FDS) and backward (BDS) digit span scores (P<01).39 A similar commonality between intelligence and working memory was found in animal studies. Matzel below and Kolata47 reviewed several reports in which performance of laboratory mice was measured in a variety of attention and learning tasks. These are their most prominent conclusions: The “positive manifold” (eg, scores on cognitive tasks of various kinds are positively correlated) found in humans also applied to mice Storage and processing components of working memory accounted for the strong relationship between this cognitive function and g Networks involved in working memory overlap with those relevant for intelligence. These findings support an evolutionary conservation process of the structure and determinants of intelligence beyond humans.48 Giftedness has been also investigated with related findings.