I just rewatched Bliss (Star Trek Voyager 5x14). In this episode the alien of the week causes the whole crew to fall asleep with a neurogenic field except for Naomi Wildman, the doctor, and Seven of nine whom Naomi manages to wake up. The reason the doctor wasn’t affected is obvious, and I’m assuming Seven wasn’t affected because of something Borg-related. However, I can’t figure out why Naomi Wildman didn’t fall asleep. Did I miss some hint in the episode?
It's stated in the episode that the "pitcher plant" attracts its victims by presenting an illusion of everything they ever wanted - in Voyager's case, a wormhole leading back to Earth, and the possibility that all their lives are going to turn out okay (Note especially how Chakotay, a literal terrorist according to the Federation, is offered a prestigious teaching position).
According to the episode, that's why Seven of Nine and Naomi aren't affected: they don't actually want to go back to Earth; Seven is afraid of how she'll be received, and Naomi thinks of Voyager as her home.
As a hand-wavy scientific explanation, it's possible that the neurogenic field reacts with brain chemicals like serotonin to put victims to sleep, and making the crew happy was just an easy way to accomplish that.
I'm personally not really satisfied with that explanation. Another possibility is, as you say, that Seven was protected by her Borg implants. Namoi may have been protected because she's half Ktarian; it wouldn't be the first time we've seen a mixed-species heritage provide immunity against the Threat of the Week.
It's explicitly stated by the EMH that the reason why Naomi and Seven weren't affected is because the creature was simply blasting out a very generalised fantasy to each of the crew using its neurogenic field (e.g. feelings of 'home') and allowing their own minds to fill in the blanks. The field itself doesn't cause sleep, it's the acceptance of the fantasy world that leads to the comatose state:
Seven and Naomi both consider the Voyager to be their home and are therefore immune but note that Seven's immunity dissipates after it changes the illusion to something more specific to her desires.
SEVEN: We've cleared the organism.
QATAI [on monitor]: You've been deceived. We're both still inside it.
EMH: He's right. I'm reading bioplasmic energy.
SEVEN: I am impervious to the creature's influence.
EMH: You were impervious, when it was creating the illusion of Voyager getting home, because you didn't share that desire. But now we're trying to escape, which is what you want.
This isn't the first time the crew have encountered a neurogenic field. In "Waking Moments" a similar field is used to project a shared dream to the crew:
EMH: A neurogenic field created by heightened electrical activity in the brain. It's been occurring in all the sleeping crew members. And that's not all. This is Ensign Kim's brain wave pattern, indicating that he's dreaming in a hyper REM state. This is Crewman Foster's pattern.
CHAKOTAY: They're identical.
EMH: Lieutenant Torres, Captain Janeway, Commander Tuvok. I don't know what it means.
CHAKOTAY: I think I do. Not only are they dreaming, they're all having the same dream. It wasn't just my dream, it was a communal dream.
"As Voyager returns to consciousness and sets course to the Alpha Quadrant, Qatai is seen returning to the creature. It remains unclear whether Qatai is intent on destroying it or simply returning to a life of delusional captivit"
Found It i Guess ,, But makes me Wounder :-) God do i love Sifi