when one Citta perishes,from where does the next arise?
Citta arises from mentality-and-materiality (nama-rupa). As long as the physical body (materiality) is alive, cittas will continue to arise.
Note: citta is of the same substance as consciousness.

Mentality-and-materiality is the cause and condition for the manifestation of the consciousness aggregate. SN 22.82
With the origination of mentality-and-materiality there is the origination of
citta. With the cessation of mentality-and-materiality there is the passing away of
citta. SN 47.42