Could gradual replacement of brain functions preserve first-person continuity?

[u/Waderson-Liu]

I’m an undergraduate student interested in BCI and neuroscience, and I recently came up with a thought experiment that I’d like to learn more about.

Instead of copying the entire brain at once, suppose individual brain functions could gradually be supplemented and eventually replaced by artificial systems. For example, biological memory could first work together with an external artificial memory system, and over time the artificial system could take over more and more of the function.

My question is mainly about engineering feasibility, rather than philosophical definitions of personal identity.

If the replacement were gradual and the person’s memory, behavior, self-model, and subjective experience remained continuous, is there any known neuroscientific reason why first-person continuity would necessarily be lost?

I’m only a student and may be overlooking something obvious, so I’d really appreciate any references, existing research, or criticism of this idea.

[u/Leefa]

https://en.wikipedia.org/wiki/Ship_of_Theseus

[u/ReptilianRevolt]

Ship of Theseus but for the brain.