Maybe in the anime. I'm pretty sure that in the manga - at least originally - she's got her native brain and spinal colum. IIRC, it's mentioned during one of the side stories, when she's watching a full-body conversion being done, and though I don't know for absolute certain, I believe having those is required to be classified as human. After Batou gets her out at the end of the original, I grant that she'd had an entire ghost transplant (as it were), but up until then, she does have the original hardware 'upstairs'.