The following information has been captured by an archivist for posterity from an AGIS press release, dated 2490-09-29
AGIS is pleased to announce that a brand-new Recap facility is approaching completion in INSILICO. Whilst some citizens may be au fait with the technology, for the benefit of all we offer our own summary. Recording memories, in part or in full, has been researched for decades, and the technology in cruder forms has been accessible to those of considerable means for many years; since 2478, it has been commercialised and consumer ready. But how does it work?
The science of Recap
By exploiting the ubiquity and fine resolution of the neural net, it is possible to "record" the state of a brain at a given time. The neural interface itself can be precisely controlled by specifying oblique polar coordinates, and entering what would be an effective diagnostic state. By manipulating the neural interface to overdrive the fine mesh webbing of the net at those coordinates, states can be read or written - for each junction on the web that surrounds the brain, an impulse is directed at a normal to that, just under the neuron action potential. Every other web junction is momentarily a detector for the impulse, the values at the detection points representing the curve integral along the pathway between the source junction and that detection point. Each response - the value and position - is precisely recorded.
Storage requirements vary depending on the size of the memory being captured, but this scales as a function of the square of the number of neuron-synapse states recorded. A simple experience - a stolen kiss in the rain, or a high-octane sports activity - might only run to a few dozen terabytes. A complete neural capture - uncompressed - might consume hundreds of exabytes.
This is repeated for each junction. Where there may be Nyquist-deficient information, multiple neural net pathways may be activated to allow cohesive deconvolution of the signals to correctly recover the signal, at the expense of time and storage space.
The brain can then be principally reconstructed during the recovery process - the neural net pulses every junction as a transmitter, individually, with the target junction set to receive the signal. This then repeats with every other junction in turn as the target. Each cycle, the same process as the capture is performed to verify the "closeness". If it is outside tight tolerances, then it is repeated until the operator is satisfied that the error delta is residual.
It is a significantly more time-consuming process by orders of magnitude to restore the memory than to acquire it, taking several hours for a complete recovery - for example, the state-of-the-art AGIS Redux/Recap facility in INSILICO has some of the highest bandwidth neural transfer capacity available, of the order of 100 petabits per second, and a typical recovery for the reference human model has been benchmarked at just under three hours.
Advanced Recap facilities have adaptive in-line procedural error correction to manage synapse displacement and neuronal approximation (where a functional neuron) - the brain itself is replete with multiple pathways for the same operation, and this intrinsic resilience can be leveraged to ensure that even a non-perfect biological copy of the brain is still able to receive the memories. There is more latitude with selective memory implantation; multiple suitable sites for a smaller memory exist within any organic brain.
Specific memories can be identified by the subject concentrating hard; this should allow the associated neural activity to be pinpointed. More recent memories also leave a chronographic tracer based on residual memory formation activity as the neurokinetics settle from short- and medium-term, to long-term synaptic storage
Note that memories being formed at the time of capture, can result in a "blurring" of the most recent memories, most obviously during the acquisition process. This may manifest itself, for example, as a sensation of the acquisition procedure being experienced with all perceptible discrete time frames occurring simultaneously, saturating the brain's memory processing centre and anecdotally appearing as a "bright white light" some ascribe to passing from the mortal coil. However, some people report that the memories formed prior to those of the capture procedure are temporally compressed, resulting in a much more vivid recalled experience than how it originally felt at the time.