A cortex constructor is a device that interprets recorded brain state information and reconstructs the neural pathways for memories and intelligence in inert clones. The development of the cortex constructor was a vital part of allowing cloning to be a viable method of death avoidance.
The cortex constructor was first developed in YC 27 by researchers in the Lai Dai Corporation. At the time, neural scanner technology had already been developed several years earlier, but methods of utilizing its data to reconstruct a brain were crude. Early methods relied on physical nanotech sculpting of the brain. This was a lengthy process and often led to scarification of the gray matter, causing a myriad of neurological problems.
The solution was no great breakthrough, but rather a combination of a number of preexisting technologies. The exact combination of them, however, was innovative and creative. The earliest cortex constructor was still relatively crude, being capable of only recovering approximately 50% of a brain's memories. Further refinement over the years gradually increased the reliability of the constructor, to where now nearly 100% of a patient's memories can be reliably copied.
Once a clone is bought, a thorough brain scan is made of the client to determine the shape of the brain and the placement of nerve cell nuclei. Then a three dimensional gel structure that matches the shape of the client's brain is constructed.
The cranium is constructed by seeding this gel structure (heavily impregnated with nutrients and inactivated growth factors) with nerve cells and glia, in accordance with information from the brain scan. Bound to the growth factors are molecular receptors that are coupled (using FTL-communication technology) to molecules placed in the customer's burning scanner. After seeding, the gel structure is suspended until the final moment of the original. As the burning scan is made, the molecules bound to the inactivated growth factors become unstable and cause activation of the growth factors by cleavage. The activation is an exothermic process which produces sufficient heat to melt pathways into the gel model of the brain. Thus dendrite paths in the model will be the same as in the original's brain, their growth fueled by the activated growth factors
This process alone is not sufficient for an exact replica of the original's brain. The precise shape of the dendrites and the potentiation level of the synapse, which together determine memories and skills, have to be fine tuned through a neural link. Impulses are sent through the link to stimulate further growth and shaping of the dendrites, until they fill in the paths formed with the activation process. In the final stages of this tuning, as the clone regains consciousness, potentiation at synapses is quickly adjusted to recorded levels, generating a feeling often described as one of memories "coming back".