In order, and briefly:

• In Milwaukee protocol, you are giving people ketamine and some benzo to silence brain activity. Ketamine inhibits NMDA channels - which means that presynaptic neurons can still fire, but the signal won't be fully received. Benzos make GABA receptors more sensitive to GABA - so they don't do anything unless GABAergic neurons are still firing normally.

In essence, this tunes down excitatory signals, while tuning up the inhibitory signals. It doesn't actually stop either, and it certainly doesn't interfere with the signalling processes within the cell.

• You are mixing three different processes here. First is cooling down. Cooling down is not the same as freezing. There are examples of people who went into deep hypothermia, and were revived even after not breathing for tens of minutes, with little to no brain damage. If the plan was to cool down human brains and then bring them back within a few hours (or maybe even days), I would put that into "possible" category.

Second is freezing. Some human neurons could survive freezing, if properly cultured. Many C. elegans neurons do not survive very deep freezing. It depends on the type of neuron and its processes. Many of your ganglionic neurons might survive freezing. Large spiny neurons, or spindle cells? Completely different story.

The third is freezing plus cryoprotectants. You need cryoprotectants, otherwise you destroy most cells, and especially most fine structures. But then you get membrane distortions and solvent replacement, and everything I've been talking about in other posts.