It doesn't have to be.
Neurons are created and die all the time. Replacing them one at a time, with their virtual equivalent, would not be entirely different to what is already happening.
Neurons are created and die all the time. Replacing them one at a time, with their virtual equivalent, would not be entirely different to what is already happening.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3106107/ https://www.nature.com/articles/nm1198_1313 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812798/
However , in the scenario that single neurons are replaced with artificial copies with exact same synaptic weights, then yes they are functionally equivalent. It's already happening, with deep brain implants etc.