If some children are able to recall past lives, then obviously memories must survive death. In this case, it is probably at some other level of being. Christians might say at the level of soul. Other possibilities are the astral body, and so on.

In more general terms, Rupert Sheldrake's theory of morphogenetic fields is interesting. Also his book The Science Delusion has chapters 'Are Memories Stored as Material Traces?' and 'Are Minds Confined to Brains?'