being linked as a node to a larger collective does not erase the individual
mind, or its porcesses. My computer links to the net. Your computer links to the net. But that doesn't mean that our computers don't maintain their individuality.
There are different aspects to individuality and the language used to talk about it on trek is imprecise. However it would be rational to assume that personality and ego are both lost by communion in the collective but that individuality is not. 7 of 9 reports being a thinking being as a borg and reports having her own thoughts as a borg.