Disclaimer!
This post is not about enforcing any style of play or presuming to provide mechanics or a status quo of how to deal with character death and resurrection. It is solely something that I found fascinating that could also be applied to RP situations and wanted to share. I will make some claims as to things that will or will not work - it's not a declaration for anyone to do or not do something; it's simply the manner I am choosing to write about this from the perspective that it is being approached from, which is a physical (neurological) and psychological one. I found this interesting by itself for what it is, and helpful to my own paradigm on it as it relates to RP and I hope other people will find it interesting as well! I'm also doing this because engaging with the subject solidifies it in my own memory - how meta! The information I'm conveying here is primarily from a current psychology textbook, with some interpretations on how it would relate with the Realms.
/disclaimer _________________
A quick and dirty summary as it relates to memory retention and character death:
There has been a lot of discussion on memory loss and death as it relates to PCs, about if the loss is a result injury to the mind, body or even soul. Based on what I will be explaining, no injury actually need occur at all for there to be to be no retention of the information gained leading up to a PCs death or trauma because of the way that
short-
term
memory (STM) becomes
long-
term
memory (LTM); this is a process that can be interfered with.
If the information taken into the short-term memory is not "written into" the long-term memory by some method of encoding, typically repetition or rehearsal, that information ceases to exist once it leaves short-term memory. Various things can impede the process of moving information from STM to LTM and even if the same information is later encountered but it was not moved into LTM, one would not be any more familiar with the subject from their previous exposure to it because the information was
actually lost.
"After long-term potentiation has occurred, passing an electric current through the brain won't disrupt old memories. But the current will wipe out very recent memories. Such is the experience both of laboratory animals and of depressed people given electroconvulsive therapy. A blow to the head can do the same. Football players and boxers momentarily knocked unconscious typically have no memory of events just before the knockout. Their working memory (short-term memory) had no time to consolidate the information into long-term memory before the lights went out." (pg 341)
Long-term potentiation is believed to be the neural basis of learning and memory which increases the efficiency of the synapses - essentially lubricating neural communication and strengthening the signal lines. One could consider it as turning a path you have traveled for the first time (STM) into a paved road (LTM) which is effectively permanent once the asphalt is down; but unless the route is practiced and cleared, the way will be lost.
There is also a whole other side of memory in aspects of forgetting and storage decay, but for this subject the focus is more on the interruption of retaining the memory in the first place.
Coming back to life In the Realms, if a PC is revived through use of Resurrection or True Resurrection then all damage to the body is entirely repaired and - in the case of True Resurrection especially, where even the body itself is not required to Raise the PC - it can be assumed (although it is not explicitly stated) that the character is essentially fabricated a brand new body, as they were before their time of death. Therefore, removing the head of an enemy or completely destroying their body is irrelevant to effecting their memory.
What is relevant to effect their memory is the death itself, no matter what form it takes or how non-traumatic or non-violent it is. Death becomes an interruption which prevents the information in the STM from becoming information in the LTM. Because this information has an expiration - from a couple of seconds to as long as several minutes, depending on the situation and information - as well as a finite capacity, it must be processed by encoding or rehearsing the information for it to actually become saved. The chemical and electrical process in the brain is impeded by the trauma (i.e. death) and even if the PC were returned to life in the exact same state, the same synapses firing and the same neurotransmitters being released - as if copied and pasted from the memory right before their death, back into life - the stimuli is now gone and there is no information to rehearse and store. At most, a fleeting sensation of arousal (as is, a state of heightened activity, not exclusively sexual) might be experienced, especially by characters who have been in similar situations (and survived) to form a strong potentiation for near-death experiences, as long as the circumstances were largely similar: engaging in frontal warfare time and time again would have the potential for greater memory retention or less memory lost (up to a point), but being assassinated without warning would not. Any sudden trauma without context would have nothing to "grasp" on to and any memories would be non-existent or fabricated/imagined.