In one of the Super Digest Books (60+) Gosho implied, that the drugs from Akira were an inspiration for the APTX 4869 (or at least it's capsule form). I read about that for a bit (I've never read or seen Akira) and found out, that these seem to enhance one's own strength, the senses and - as far as I understood - also psychic powers/ESP, to a certain degree.
While I really doubt the existence of ESP in the world of Detective Conan, I'll try to define the "sensing" (like Ai's "organization sense") in DC more precisely - the whole thing is unrelated to Akira, but it gave me the initial idea for it:
To summarize, in one of my older posts in a german forum I talked at length about how the project of the organization could be a kind of "supersoldier serum", which enhances the stamina, sharpens the senses, and so on and so forth. (I can translate that post for reference, if you want. Just tell me if you want me to.) But, maybe it's even simpler than that and the APTX should (for now?) only do the latter one - pure "superhuman" senses. (The quotes are deliberate, since I'm not talking about breaking reality.) Please let me explain on the basis of some possible hints from the Manga and by Gosho himself:
According to Gosho, immortality isn't the aim of the organization:
From the Da Vinci Interview, translated by ALAKTORN wrote:どうか！ どうか、あと二つ質問させてください！ 黒ずくめの組織の目的とはナニ？ APTX4869の作用から考えると、不老不死が怪しいのでは……。
Please! Please, let me ask 2 more questions! What is the BO’s goal? Going by the APTX4869, I would think immortality…
That’s wrong. It’s true that you’d think that, isn’t it? You see, right now, something really big is happening within the organization.
On the one hand, Elena Miyano described "Silver Bullet" as a "dream drug", which could already remind some people of Akira (but like I've said, this theory can work without that relation ); but it would also be a "terrifying drug" or one, that should never have existed in the first place, because it could be alienated (like almost everything on this world, I admit XD). The APTX was the attempt of directly reconstructing the Silver Bullet on the basis of the (unburnt) papers of the Miyano parents:
File 948, page 4, Ai Haibara, referring to Silver Bullet wrote:Perhaps it was an early prototype of the drug made by my parents... The information for the drug that I created was mostly taken from the burnt remains of the data that my parents left behind...
But it would also be a product that isn't (immediately) identifiable as suitable for everyone:
After the seemingly playful statement that it's "a concoction which can revive the dead! Do you want to hear something like this?", Ai says that Conan shouldn't worry, because her research wasn't about some "figment", but a „ridiculous product that almost no one on this world values. [...] Just like these puppets, which are only... important for the girls of this small country.“ (Translated from the german version of the Manga, volume 38.) This sounds like it's something many people would see as pretty mundane or not all that useful; but could carry a lot of (criminal?) potential. And it's a heavily cell-oriented drug - just like the senses rely on cells (sensory cells):
File 241, page 9, Ai Haibara wrote:Shinichi, you have to listen closely now... As you know, the poison which shrank our bodies is called APTX 4869. The APTX stands for "Apoptoxin" and the "Apop-" in it stands for apoptosis. Apoptosis is the technical term for the programmed cell death... Cells can kill themselves off. This is a vital mechanism for our organism. If the signal for it is suppressed, the cells stay alive... [...] But the poison in fact not only induces the apoptosis, it also starts a telomerase activation, which in turn causes an increase of the replication quantity of the cells...
It also seems that Shiho should neither create a rejuvenation drug or a poison:
File 179, page 9, Ai Haibara about APTX 4869 wrote:It is not like it was my intention... in the first place... to create a poison...
Based on this, the (accidental) "poisoning function" of the drug rather seems to be a lethal chain reaction inside the cells of the body (making it an untraceble murder weapon), which doesn't work like this in every body - for whatever reason (and I really don't have a clue why that is, if we ever get a detailed explanation for this). But let's continue: After the discussion about the use of the concotion 17 years ago in the Haneda/Hughes double murder in the United States, after Conan asking her again if she's really 18 (because the drug was used such a long time ago) and after the explanation on her behalf that the APTX was based on the Silver Bullet, she has an internal monologue:
File 948, page 4, Ai Haibara in her thoughts wrote:But what they really wanted me to make... was another drug...
On the other hand, Pisco said back in volume 24, after watching Shiho shrink back to the form of a child:
File 242, page 9, Pisco wrote:That's really impressive! You probably don't remember me, you were just a little baby back then after all, but I was a good friend of these scientists, your parents... I've heard a lot about the drug which was in the works back then [...] But who would have thought that you would bring it that far... Your parents, who died in an accident back then, probably would be proud of you...
... implying that rejuvenation does go into the right direction, in some way.
Now, my idea is that it's about "rejuvenation" of sensory cells, who go into decline in a natural way while aging - which means, rejuvenation goes into the right direction, in a sense, but it was "too holistic", so to speak, which in turn makes the drug "incomplete" (Gin in volume 24: „the incomplete detective“, or alternatively „the detective in the fledgling stage“ in the german version). In the case with Kirin's Horn (File 712 - 715), in which Jirokichi Suzuki intentionally wanted to have the Detective Boys around, an effect associated with such phenomena is vividly shown, by using sounds on a frequency only children and young people can hear - like the Detective Boys, who are around 6 to 7, including Conan Edogawa and Ai Haibara, who are in this biological state thanks only to the APTX. This is like the principle "The Mosquito" works with, which is even mentioned in this case.
This could be a more precise explanation for Ai's "special sense": A rejuvenated, extremely sharpened sense (maybe even with the almost animalistic talent to subconsciously receive olfactory, visual and acoustic stimuli caused by another person - be it through normally not sensible frequencies, pulse/heart rate, sweat, subconscious movements on a micro-scale, etc.), which can narrow it down when one feels instinctively that someone else is wanting to cause harm - or the subconscious at least perceives it like that. This could also explain why Ai's sense isn't really selective (which means, not really a "BO sensor", as you can see with Shuichi/Subaru, for instance) and doesn't work every time (Kiichiro Numabuchi, for example).
Someone could interject: „But wait! Why has Conan got no gift/sense like that then?“ That's the point: He has. Just remember several scenes (I have to look up their numbers, admittedly) in which Conan felt the "murderous intention" of the culprit or sensed him/her in a group of people; just like he felt Kid more than once (instantly in the first case about the "Black Star" on board the Queen Selizabeth and just recently in the library, when Kid - in disguise - secretly stares at Conan).
I know that Conan doesn't fly off the handle just like Haibara does (even though it looks pretty similar in the page linked above); but she probably got some severe traumas from her past membership and quickly associates every shock moment with the organization, kinda like a negative déja vù - hence her (over?)reaction most of the time; additionally, Conan isn't frightened that easily, as far as we can tell and in the case of Kid doesn't even feel any fear, for obvious reasons. That it can also decline or be "switched of" altogether, in her case, was shown in a clear manner in the seemingly paradox scene, when she didn't sense both Bourbon and Vermouth together (maybe because of her new feeling of safety interfering with it), which also makes Conan ponder about that.
After a conversation with Sephiroth from the german board about this theory, he also said something interesting:
Who would most people associate with "sharp senses"? A detective of course, and the most well known surely is Sherlock Holmes, who also got a leading (meta-)part in Detective Conan. And interestingly, the APTX 4869 is named after Sherlock, because - as most people on here probably know - the "4869" can also be read as "Shiyaroku" in Japanese, the phonetic spelling of "Sherlock". The same goes for the "incomplete detective" or "the detective in a fledgling stage", besides the password for the APTX data of the organization being "Sherringford".
In the end, the question left unanswered for me in the context of the theory is how Itakura's software figures into all of this (if there even is a (direct) relation) and why the organization would need a super senses inducing/sense-enhancing concoction. Is the creation of this drug the ultimate goal and if so, what for? Or is it just a stepping stone in an even bigger plan, which is relying on "superhuman" senses? A drug which can enhance the senses in such a manner also contains a lot of criminal power in itself, like I've mentioned before. But is there something specific on the mind of the organization, making such a drug worth all the years of hard underground research work?