1. MRI livefeed - I think MRI might require special nanos in the brain, and/or hardware addons to the ecto. But you can do life-blogging which IIRC includes all the senses. Don't remember if it includes your thoughts or just your actions. (live vs prerecorded just depends on how good is the local mesh) 2. Ecto sense limits: An ecto definitely can override sight and sound. Has to do that for things like petals and an AR that makes your coffin-sized apartment look like its in a wide-open vista, and Muzak in your head. But, this is post Fall. I expect freeware patches with the best Antivirus, and a patch adding some sort of hardwired killswitch. People are really scared of toombies nowadays. https://en.wikipedia.org/wiki/March_Upcountry So blindness etc could happen, but you have to hack the ecto first, and even then the user could get rid of the sensations in one action. 3. Stacks. In the fiction we have seen people remembering up to unconciousness (kid at the base of the space elevator with Ultimate rescuers). We've also seen "if you get Watts-Mcleod, you can only fix it by going to a pre-infection backup." To me this implies stacks record everything until the brain starts shutting down, and that the stack only holds the one copy of you, no emergency fiddly bits. That said, unintentional or icky death is why there are psychotherapists and technology to erase a section of memory. Also, if a character really worries about this, buy the "Spare" synthmorph. Easy to carry, you can send a backup from your stack to it whenever you think of it. For something like clearing out a Cthulhu space station, you can even copy to the Spare before you go in, then restore from Spare if you get out. Suddenly, you know that you attacked the station but you don't remember any freaky bits. (Memory oops. Everything I said about ectos was actually referring to a muse. Mostly not applicable to ectos)

So, with your references to overwritten, bandwidth, slowing the update, etc. Looks like you are assuming a stack structure similar to 'store a base brain image, every second store the deltas relative to that base image, use a circular array for the deltas". Makes sense. My assumption was closer to 'stack has a brain image, directly changes the image in real time, and doesn't have capacity to store anything more'. Closer to how the image on a PC screen (or a tv) gets completely redrawn every refresh. My stack concept has much less capacity but a really fast update speed.

None of those are nanoswarms though, which should have pretty limited long range communication abilities.

I've always found it absurd, the idea that there's only a single backup and nothing else. It's come up in a couple of threads I've read through, but most of them were old and settled, so I didn't feel it appropriate to chime in. In my mind, the only reasonable solution is that there's at least two backups, and the most-recent backup only replaces the existing backup after an integrity check. In the event of integrity errors, it parses the sections that aren't broken together, before a new copy goes into the system. The "current" scan is ongoing, and goes into a buffer before being parsed over the permanent backup, meaning that the scan itself does not have to take less than a second, but it is instead, rather, and ongoing scan where the segments scanned goes through an integrity check before being saved. So in the scenario in which you take a bullet to the head, you'll remember parts of it, insofar that undamaged sections were still alive and were being scanned when the bullet entered your brain, and they were parsed onto the final backup. However, all the wounded, unscannable or simply missing sections turn up empty, and are discarded, and an error report is filed. This may continue several minutes after clinical death, but since these scans will most likely only be returning errors, failing the integrity check, they will not be parsed onto the backup. And the cortical stack likely goes dormant soon afterwards, to prevent tampering. This leaves the reinstatiated person deeply disoriented upon resurrection in a new body, as they must deal with the last feelings of complete euphoria, utter dread, and possibly crippling pain and panic as the brain shuts down, all at once, since different sections of the brain could be upwards a couple of seconds apart in their collective experience. Imagine the situation if you only had half a brain. Because there are people that do that in real life (http://www.bbc.com/future/story/20141216-can-you-live-with-half-a-brain). However, imagine that you had a backup from before you lost half your brain, carried on living for a while, and then half your brain was restored based on that old backup, but half of that old backup was not, because that part is obviously already there, and it's a newer, version anyway, and healthy. That's the kind of parsing I'm talking about. So in my headcanon, it's not an instant backup of your entire brain at once, but a system of continuous scanning, integrity checking, and parsing - and it takes about a second for a full scan. And yeah, unless the schizophrenia (which is largely weeded out, except for flats, afaik) is the result of physical trauma or something detect-able by the system during an integrity check (which it may very well be, leading to synchronization issues and parsing errors in a cortical stack), the mental illness in question would absolutely still be there.

we do have a rough volume for the stack. A grape. In my mind specifically a concord grape :)