Brings up a good point, nirodha-samapatti is in the discourses called sanna-vedayita-nirodha, right? Cessation of apperception and feeling. The prerequisite for nirodha is the fourth aruppa, so from neither-perception-nor-non-perception, the last residue of perception is abandoned, along with feeling.
Is this really a complete stop, as is sometimes said? I dunno.