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 size (either the whole brain, or a part of the brain such as the neocortex or frontal lobe). How do other species correlate compared to us? Either in absolute brain size, or in brain size relative to body size.