Nope when they say water is being reabsorbed they mean that water is apsorbed that was excreted by the mouth (saliva) and stomach (stomach acid).
This adsorption takes time and you can notice this when you visit the toilet after you at something like raw food. Your body will want to get rid of...
It could also depend on what thought your trying to access. This is explained bij how many 'steps' it takes to get to the memory your trying to remember. The steps vary from each other on the length of the axon.
Also memories are not just one nerv, they come in networks linking to other...