question

Hello anybody,

does someone know what distinctions Foucault draws bewtween individual,
self and subject. I'm specially interested in the notions of self and
subject. As far as I understand subject is used as a "secondary"
position which is opened up by discourse, and self seems to have
something  to do with ethics in a wax that it is field or realm which
one has to work on. 
However, is there also a notion of self within the field of knowledge or
power?
Can someone help?

Thanks

Arne