[user104658]

In terms of the rat hemispheres experiment, in order to understand why they still remembered the tricks all you really need is an understanding of how RAID redundancies work for things like web servers.

Web servers have multiple hard drives that work in unison. All of the data is on both drives. If one drive dies or is removed completely, no data is lost because there's an exact copy on the twinned drive (or however many other drives are in the array).

So why could the rats remember no matter which half of the brain was removed? "Where" is the memory stored? Answer is simple enough: there's probably a copy of the memory on each hemisphere.