past memory of recall previous life
Think of the brain as a proxy server connecting you to the internet(all past life memories). Just because your browser can only see the proxy server, is it wise to assume that the whole internet is contained in the proxy server? 

Think of the electrical traces stored in neuron cells as the information stored in the cache memory of the proxy server. If somebody alters or adds new content to the cache memory, it will be shown on your browser. Then is it wise to assume that the whole internet is just electrical traces stored in the cache memory of the proxy server? 

The brain is simply a tool used by the mind. Mind doesn't cease to exist even if the tool breaks.