The study investigates the relationship between the efficiency of functional brain networks and intellectual performance. Using resting-state functional magnetic resonance imaging (fMRI), the researchers examined the functional connections of the brain network, which are organized in a small-world manner, characterized by high local clustering and long-distance connections for efficient global communication. The normalized characteristic path length (λ) of the resting-state brain network was found to be strongly negatively associated with intelligence quotient (IQ), suggesting that more efficiently functionally connected brains exhibit higher levels of intellectual performance. This association was most pronounced in frontal and parietal regions, particularly in the medial prefrontal gyrus, precuneus/posterior cingulate gyrus, and bilateral inferior parietal regions. The study also found no significant correlation between IQ and the clustering coefficient (γ) or the total number of connections (k) in the brain network. These findings indicate that the efficiency of global communication within the brain network is a key factor in determining intellectual performance.The study investigates the relationship between the efficiency of functional brain networks and intellectual performance. Using resting-state functional magnetic resonance imaging (fMRI), the researchers examined the functional connections of the brain network, which are organized in a small-world manner, characterized by high local clustering and long-distance connections for efficient global communication. The normalized characteristic path length (λ) of the resting-state brain network was found to be strongly negatively associated with intelligence quotient (IQ), suggesting that more efficiently functionally connected brains exhibit higher levels of intellectual performance. This association was most pronounced in frontal and parietal regions, particularly in the medial prefrontal gyrus, precuneus/posterior cingulate gyrus, and bilateral inferior parietal regions. The study also found no significant correlation between IQ and the clustering coefficient (γ) or the total number of connections (k) in the brain network. These findings indicate that the efficiency of global communication within the brain network is a key factor in determining intellectual performance.