Regeneration, Simulacrums, and the Idea of the Neural Linkage:

Simulacra

Simulacrum, or plural simulacra, are the robotic pilots that we can play as in Tf2's multiplayer, as well as Ash in the campaign. These simulacra are more than just robots, they are pilots brought back from the beyond, in digital form. "The idea was a human had uploaded its consciousness into a synthetic body". There is also additional evidence the McFarlane Action Figure of the cut character Jester who, "is an experimental IMC Simulacrum, based on a deceased, highly decorated IMC operative."

With this evidence, simulacrums are indeed based on human minds. It also seems that these minds are not just uploaded into a synthetic body but backed up onto some kind of storage device for replacement after every death. When Ash is killed in the campaign, she is utterly and completely destroyed by B.T. and Cooper, execution or not. Anything left would have been destroyed by the scuttling facility, and disintegrated by the Ark explosion that destroyed Typhon. There is no way Ash's mind could have been recovered from her body. Yet she still makes an appearance as a field commander for Vinson Dynamics in Tf2's multiplayer, which takes place after the campaign and thus her death.

We can tell the multiplayer takes place after due to the bounty boards of Jack Cooper in Angel City, and from the deployment of Stalkers by the Militia who only first encountered them in the level Blood and Rust. The only way for Ash to have been rebuilt is if there was a backed-up version of her mind. But how are the minds exactly are the minds uploaded? For that I have to explain regeneration, and its link to simulacrums.

A simulacrum is a digital backup of a select individual's memories, knowledge, and personality. It is unknown precisely how Simulacra are made, but their most common application among the IMC and Frontier Militia was to preserve a valued Pilot whose original body was destroyed or damaged beyond repair. A copy of their digitized consciousness is downloaded and installed into a man-sized robotic frame, allowing those Pilots to live on and continue fighting.

Due to their human personalities and to maintain vestiges of their past humanity, Simulacra will often decorate or customize their chassis with trinkets or clothing, despite not having a practical need for them. This can be seen in the raccoon-like ponytails serving as "hair" sported by Phase Shift Pilots or the hood and mask worn by Ash, for example. A Simulacrum will still typically identify themselves as masculine or feminine, as well, and this is reflected in their chassis - not only can they speak with a masculine or feminine voice, but also a "female" Simulacrum has a more pronounced bust.

Not everyone takes well to the reality of their situation when they find themselves to be a simulacrum - in fact, during "Project 617", the project to develop the Simulacrum, it was implied that seeing themselves as such causes the operation to fail. As such, the ego retention system, an essential program, is used to shore up the simulacrum's mental stability by ensuring they never realize that they are a simulacrum at all, that they are still their former self with a normal body; any visual or verbal hints that they are a simulacrum, the programming will censor, such as changing the word "simulacrum" to "Pilot". They may keep their old habits or routines they once had in life. However, they may occasionally snap back to reality violently. Ultimately, any damage to the ego retention system appears to have significant psychological consequences. The complete original identity of the simulacrum is typically suppressed, and a total awakening of their identity - that is, a simulacrum not only being aware they are a simulacrum but also recovering the identity of who they were in their proverbial past life - is considered an impossibility without external intervention. Only two cases of complete awakening are known in the modern age: in the case of the prototype assassin (and the first to become a simulacrum) Revenant, his awakening was due to a glass shard interfering with his circuits; Ash, a later model, had additional programming fail-safes in place to prevent such to occur, but she was still awoken and freed from her programming by listening to a sequence of codes that, when used, is comparable to "cracking an egg with a jackhammer".

Components:

Gemini-XG Core - Responsible for higher functions and memory. Etchings "XG" type. One half in a rare Gemini configuration, required a resonant twin core to function. Holds a complex crystal matrix at nanoscale. Any compromise of housing would instantly reduce said matrix to dust. Unit is very tough on the outside, and gossamer on the inside. Casing appears intact.

Gemini-CC Core - Second process core, identified as "CC" type; entangled to the "XG" twin in a gemini configuration. The crystal matrices in these cores required constant power cycling from an external source to stay pliable and functional. When power was lost, they hardened and went dormant.

Occipital Hub - Physical and logical connection for the entire assembly. Delivered constant conditioned power to cores. Passthrough channel for direct data between cores and an encryption sub, but no tap for the hub itself. Holds motor subprocessing. Interfaced and translated between host structure(s) for locomotion.

Retinal Array - Optical assembly of very high quality.

Faraday Armature - Shielded other components against a wide range of electromagnetic and electrostatic interferences, while also providing an ideal resonance environment for the cores. A grid of contact pins across the back has no termination.

Scomp Housing - Provided encryption/decryption services to downstream parts that had passed authorization. This is the only interface that the cores would have ever talked to in Raw-0 or Raw-7 modes. Lack of a handshake keybank; instead auth sync was provided by the faceplate.

Idcoms Frame - Responsible for any and all communication with the external world, including vocalization and wireless send/receive. Has limited-spectrum auditory mic as failsafe/backup/confirmation for more capable hardware.

Parietal Shell - Dense battery array along ridge would have provided emergency backup power to the entire assembly in event of primary power loss - likely for weeks or months. Sensor Packs on either side gave wide-spectrum audio pickup and localized spatial feedback.

Faceplate - Visage designed to invoke ranges of emotional reaction. A vast repeating series of encryption keys embedded in substrate, and allow the Simulacrum assembly to function.

Regeneration:

Regeneration is the process in which a pilot's mind and body are restored and enhanced through the mysterious Advocate, this process also involves a level of augmentation and other surgery, with the result being Pilots who are faster and more capable of learning. However, this process has a drawback, as mentioned in the confirmation scene for both Titanfall and Titanfall 2 when leveling up. The mind must be removed during the procedure, otherwise, all the repairing and upgrading will seriously damage it. This is accomplished through neural link technology. The beginning of the regeneration scene appears to be a reversed and corrupted neural link sequence.

A flash of bright white light before fading away as green light, as opposed to green light fading in before a flash of white light. It is the opposite and distorted scene of what happens when Cooper enters his gauntlet training with Lastimosa because instead of connecting a mind to a computer and allowing for a transfer of information, the mind is instead yanked from the brain and dumped into a computer or storage device.

This is probably part of the "misappropriated and refactored IMC technology" described in the Respawn AMA. In both scenes, we see a description that a BIOS (Basic Input-Output System) is being implemented. The BIOS is a program that is used to set up a computer for OS initialization after activation, in this case, the mind is now in a process equivalent of a computer suffering a reboot.

After that, a Bootloader program is implemented, which is what starts the operating system, taking the mind from computer storage and reuploading it into a person's body. When that finishes, the BIOS is flashed, updating parts of the mind to the next generation using software on Tf1 generation symbol chips, and then the pilot wakes up.

The reason for memory loss is due to the inherent danger associated with moving the mind around during the process. To prevent any serious brain damage to the pilot, the Advocate sacrifices the memories of a pilot, ensuring that only they are lost in the procedure. Memories can be regained after all, but consciousness cannot.

By Tf2, the procedure has improved. The mind is still rebooted and upgraded, but now the pilot's memories are backed up and transferred to an external storage device. After the mind is booted up, the memories and accumulated knowledge concerning titans, weapons, and factions are backed up to the chip of the current generation, before the BIOS is updated to the next generation. Along with that new improvement to the system, the Advocate can now preserve some memories of the pilot, which then allows the pilot to live on after death should the pilot die in combat so he/she can be transformed into a simulacrum.