My undergrad is in Neurobiology, but I don't work in the field, but I can give you my understanding.

This article is basically an article that reviews the current theories regarding the neuroscience of intelligence. It's saying that there seems to be evidence of 'g' (which you could call IQ, but is the variance in cognitive abilities) that dictates the efficiency of our brain as a network of networks. It describes the brain as a interconnected global network of local networks that have discrete responsibilities. The reason these local networks to handle specific things is because it's more efficient to process in close proximity. And that the communication between these 'nodes' and the ability to tap into stored memory and intuition is described by 'g'.

their theory subdivides the brain into "local" networks, which are tightly connected and relatively stable, and "random" global connections, which connect various local regions in a more unstable manner. they propose that there are two kinds of intelligence, crystallized / persistent intelligence, and fluid intelligence. their perspective is that intelligence is governed not by specific regions of the brain, or specific networks, or specific overlap between networks, but by dynamic reorganization of various connectivity networks

note that this is an opinion article explaining an emerging theory. the theory / field of study is based in computational network models based on data from fmri and diffusion tensor mri and other methods. they do not focus on cellular or molecular biology, genetics, etc. their perspective focuses on brain organization in terms of network efficiency