>>This would also explain why days with unusual content seem to last much much longer than others (at least that's my experience).
I've heard this explained in part because of how our neocortex works. New events tend to require the involvement of more layers of the neocortex than ones that are redundant and routine. This is part of the explanation for the time dilation we experience when surprised by something like a car crash or a thrill seeking adventure. Your mind is fully engaged much the way it was when you were younger and everything was a new experience. As your mind adapts the neocortex handles the events more efficiently; more reflexively. Your mind subconsciously ignores the sensory inputs that don't surprise you.
For this reason, it's often advised that if you want to slow down the apparent passage of time just change your routine. Granted...your neocortex would probably even adapt to this.
Cortical layers tend to be more of a way of dividing a specific low-level task up into sub-functions of information processing. For example, they do different networking/interconnect jobs in different layers and as one would expect different areas of the neocortex have varying layer counts (ranging from 1 to 6).
A more comprehensive computational unit of the cortex is actually the neocortical column which is a "horizontal" patch of neocortex. This is a functional unit that is probably very close to a microprocessor in analogy in that it contains a set of variables, some processing rules, input and output wires, and the capability of executing functions. A whole patch of cortical columns forms a sort of processing center, and interestingly enough, those tend to be specialized for certain kinds of information processing tasks. That's why in an fMRI scan whole areas of the cortex tend to light up together, and it's often the same areas geographically even if you scan a lot of people.
So if we're talking about a theory of localized neocortical involvement, my first impulse would be to check out those specialized areas for (non-)activity - something that led to pretty good empirical results before in related studies - as opposed to using the layers for that hypothesis.
I've heard this explained in part because of how our neocortex works. New events tend to require the involvement of more layers of the neocortex than ones that are redundant and routine. This is part of the explanation for the time dilation we experience when surprised by something like a car crash or a thrill seeking adventure. Your mind is fully engaged much the way it was when you were younger and everything was a new experience. As your mind adapts the neocortex handles the events more efficiently; more reflexively. Your mind subconsciously ignores the sensory inputs that don't surprise you.
For this reason, it's often advised that if you want to slow down the apparent passage of time just change your routine. Granted...your neocortex would probably even adapt to this.