The central Pradeśas (the indivisible units of the substance) of the Jīva (soul)A special structure of eight Pradeśas in the centre of the innumerable Pradeśas of the Jīva; this is called Rucaka Pradeśa.
tattha ṇaṃ je se aṇādīe apajjavasie se ṇaṃ atthaṇhaṃ jīvamajjhapaesāṇaṃ.
(Bhaga 8.354)
See - Madhyapradeśa.