Knocked out is when your brain shuts out your CNS and peripherals due to damage/a lack of oxygen to the brain.
I have been both choked out and knocked out, and they felt similar. (choked out was more comfortable tho)
i have a question tho: since being knocked out is directly cranium/brain related, how is it that one can put a friend unconscious by having them hyperventolate and then squeezing their chest hard? i have done it to others and had it done to me, and it feels just like being choked out. your entire brain resets and reboots. but why? I dont understand - nothing touches your neck or head, in fact nothing feels uncomfortable. you just pass out.
im gonna google it now but i was just curious as to the principles behind it.. being a med students and also an avid mma fan i get quite curious about these things