We see Neelix's ship for only the second time in the series. It has been sitting in the shuttle bay since Caretaker (1995).
Ambassador Liria is played by Robert Pine, the father of Chris Pine who later played James T. Kirk in Star Trek (2009), Star Trek Into Darkness (2013), and Star Trek Beyond (2016). Pine is best known for playing Sgt. Joseph Getraer on CHiPs (1977), a series that also featured future Star Trek: The Next Generation (1987) actor Michael Dorn.
This is the first episode in which Roxann Dawson's name appears as such the credits. In previous episodes, she was credited as Roxann Biggs-Dawson.
47-reference: Tom and Harry have been accused of killing 47 Akritirian patrollers in a bombing, a fact that Tom boasts about at the beginning.
The Doctor informs Tom and Harry that the "clamp" implant operated by stimulating acetylcholine production in the hypothalamus, which caused increased aggression, confirming Zio's theory. Acetylcholine (ACh) is a neurotransmitter that has a number of different functions throughout the nervous system, many of which are still not fully understood, in broad strokes it helps regulate both muscle control and basic feelings/instincts like aggression, hunger, sleep and sexual arousal.
ACh's most important function is the activation of motor neurons, when ACh is released in both the autonomic and somatic nervous systems it causes the contraction of muscles, if the actions of ACh in the autonomic nervous system is blocked (by poison and/or toxins like atropine and nerve agents) it has deadly effects as it prevents the muscles in the heart and lungs from functioning. ACh also functions in the sympathetic nervous system as the neurotransmitter that helps control the most basic impulses like mobilizing the body for action, known as the "fight or flight" response and regulating rest, regeneration, digestion, and reproduction, sometimes referred to as "rest and digest" or "feed and breed".
ACh's most important function is the activation of motor neurons, when ACh is released in both the autonomic and somatic nervous systems it causes the contraction of muscles, if the actions of ACh in the autonomic nervous system is blocked (by poison and/or toxins like atropine and nerve agents) it has deadly effects as it prevents the muscles in the heart and lungs from functioning. ACh also functions in the sympathetic nervous system as the neurotransmitter that helps control the most basic impulses like mobilizing the body for action, known as the "fight or flight" response and regulating rest, regeneration, digestion, and reproduction, sometimes referred to as "rest and digest" or "feed and breed".