Despite what the top answerer says, there is some evidence that human adults can grow new nerve tissue: https://sci-hub.st/10.1038/s41591-019-0375-9 https://sci

Despite what the top answerer says, there is some evidence that human adults can grow new nerve tissue: https://sci-hub.st/10.1038/s41591-019-0375-9 https://sci-hub.st/10.1038/s41591-019-0375-9 That said, it's not like skin: we don't grow enough to pull off a complete replacement.