On Tracker Jackers in The Hunger Games, a Hypothesis of Venom Mechanism and Fear Conditioning as Hijacking
Tracker Venom is left somehow mysterious throughout the series despite playing a somewhat critical role twice. We see it in the 74th arena and it plays a critical role in Peeta's hijacking. Let's look at what we know of the venom in canon and expand that. More below the cut :)
In the 74th arena it is how Katniss is able to escape and thin the Careers. In the process of this she is stung three (3) times while cutting down the down the nest. I imagine while retrieving the bow & arrows from Glimmer's body, she was stung more times. Evidence of this is also the uptick of her hallucinations following retrieval.
We do not know how many times she was stung, but what we do know is that she experienced hallucinations and passed out for two days following the attack. We also know that (in the books) two of the Careers are killed in this attack. Additionally, the cite of the stings swell grossly and ooze a green pus.
Other than swelling and general discomfort though, Katniss seems to be remarkably fine. Thus, I am confident that this is venom is similar to that of modern wasps and just causes intense pain and swelling (not like the venom of snakes, spiders, etc which are coagulants, vasoconstrictive, etc.). So what makes their stings lethal? Location and number, primarily the former! Orange-sized swelling anywhere near the air-ways is obviously bad news, multiple would be surely lethal. In the books Katniss describes Glimmer as very grotesquely swollen, she does not particularly see or describe her death because she is getting the hell out of there. The swelling property of the stings is likely the most immediately lethal.
Now, onto the mental-- the non-immediately lethal-- aspect of Tracker Jacker venom. We know that the venom attacks the fear center of the brain and causes hallucinations and even insanity. Large doses are likely the cause of insanity, such a large congregation of fear coursing through your body would cause a psychotic break. But let's get into the specifics!
(For reference I am a trained neuroscience who has studied and conducted extensive research focused on the amygdala and fear response. Just so y'all know I'm not pulling this out of my ass lol.)
The amygdala is dubbed the 'fear center' of the brain, that is common knowledge. The amygdala's free processing passes through GABA-ergic interneurons to the Prefrontal Cortex (PFC) for assessment. Think of it like an old-school phone, the amygdala calls and the ringing is those gaba interneurons. The PFC decides to pick up (determine the fear valid and react) or not, but like irl if it gets calls non-stop it will pick up!
Tracker Jacker venom could easily target these interneurons, sending non-stop and overwhelming signals to the PFC which induce massive amounts of fear that can lead to psychotic break. There is an element of sci-fi to this (duh), but I do not think it is a large jump to make as there are drugs designed already for such purpose. This is the same action mechanism of withdrawal, where people can and do experience mental breaks. Specifically in withdrawal dopaminergic receptors (D1, specifically) in the amygdala are inhibited, leading to an increase in anxiety-like behavior. This is why those in withdrawal feel incredibly anxious and on edge (and why 'Sunday Scaries' are a natural consequence of drinking on a Saturday night!)
To relate this to Peeta's hijacking, which canonically used tracker jacker venom, we can plainly see it as good old fashioned fear conditioning. Fear conditioning paradigms vary, but they typically go as follows: neutral stimulus, CS (stimuli that does not evoke fear; ex. a sound or a light) + unconditioned stimulus, US (aversive stimulus that naturally elicits fear; ex. electric shock) = conditioned response, CR (where the CS alone evokes a fear response). For Peeta's hijacking the CS was Katniss and the US was tracker jacker venom.
The US, unconditioned stimulus, is processed by the amygdala. Tracker Jacker venom hijacks the amygdala, guaranteeing that it is a consistent and indomitable, unimaginable fear. A fear so great that the PFC will always call for a fear response: fight, flight, freeze. Peeta's fear response is fight! He is a Victor, he has survived two hunger games, his fear response is going to be fight because that response is what would've kept him alive the past two years.
Peeta's hijacking as amped-up fear conditioning also fits with what we know about his therapy to reverse it. The association between the CS and US is primarily made in the Hippocampus (HC). The depletion of this association, executing the CR, is called extension. Normally, particularly in rodent studies, time is what is needed for extension to occur. But rats are stupid... and not being injected with the most powerful fear agent in our world. Thus, he requires extensive therapy to relearn that Katniss is not a threat. That the association of Katniss = danger is not real. Under tracker jacker venom, he likely hallucinated heavily and also might've been shown doctored footage of the Games or even them back in 12. His association is very powerful because yes, he was feeling intense fear, but also that fear was cognitively affirmed by other parts of his brain as he saw with his own eyes that the fear was valid!
As we see, that is a very hard association to break. It is so hard to break because of the conditioned association, but also because he was shown things that reaffirmed it. He cannot differentiate what was real and what was not, he cannot think his way to a conclusion because they are two conflicting version of Katniss.
Okay yap sesh over! Might add more to this as I think more on it, but had a good convo about it in the DMs and thought I'd post a meditation on it for those who might be curious or are looking to understand 'hijacking' from a scientific perspective :)
