Yoga sutra 1.6
pramāṇa viparyaya vikalpa nidrā smr̥ti
Correct comprehension; false understanding; imagination; deep sleep; and memory.
This sutra 1.6 lists the five movements / mental activities (vrtti in Sanskrit) of the mind: correct comprehension; false understanding; imagination; deep sleep; and memory. These movements cannot be seen as such but offer testimony to the existence of the mind; they are as follows:
Correct functioning of the mind leading to accurate knowledge (pramāṇa);
False understanding (viparyaya) arises from poor functioning of the mind and or is tainted by presumption or prejudice;
Mental creation (vikalpa) is an extraordinary mental capacity to visualise / to learn what you are doing before it is done;
Deep sleep (nidrā) is a mental activity that can only exist in the absence of the others and it has to be just right: not to short; not too long; not ill timed;
Memory (smr̥ti) is a mental activity which enables us to recall an event from the past and/or one of the other mental activities listed above.
Damian Cadman-Jones is an authorised teacher of Prana Vashya Yoga™