As far as we know, sleep seems to be the part of the daily cycle when executive functions are resting and memories are fortifying. Many, but not all, of the functions that become dysfunctional upon sleep deprivation seem to be situated in the frontal lobe or associated with the neocortex.
My question is whether there is a correlation between percentage of the day spent sleeping and brain structure or function. Is there a correlation to IQ, EQ, any of the big five personality traits, basal activity on fMRI, relative size of frontal lobe vs whole brain, location of central sulcus etc.?