Terminal lucidity

[Eugene I]

A few links of this mysterious phenomenon:
Hospice Nurse Reveals Unexplained Phenomenon Patients Experience Shortly Before Death
Terminal lucidity: a review and a case collection
“Awakenings” in Advanced Dementia Patients Hint at Untapped Brain Reserves
TERMINAL LUCIDITY AND OTHER END-OF-LIFE EXPERIENCES

Yet, even if terminal lucidity is a genuine phenomenon, who’s to say there isn’t a logical scientific explanation, one involving some unknown brain physiology? Nahm and Greyson don’t discount this possibility entirely, but for cases involving obvious brain damage (such as strokes, tumors, advanced Alzheimer’s disease) that should render the patient all but vegetative, not functioning normally, it’s a genuine medical mystery. According to the authors, terminal lucidity also isn’t all just in the perceiver’s head. Rather, they write, “it seems to be more common than usually assumed, and reflects more than just a collection of anecdotes that on closer scrutiny emerge as wishful thinking.” This then, to them, leaves open the possibility of something more spiritually significant, with the “transcendantal subject” (i.e., the soul) loosening itself from the physical substrate of the brain as death approaches and being able to enter “usually hidden realms.”

[Eugene I]

This picture shows the brain at the advanced stage of Alzheimer's, basically about half of the brain volume and cells are gone. How can a person in a vegetative state with so much brain damage can possibly return to perfectly lucid state in full mental capacity (asking materialists of course)?

[Cleric K]

I've mentioned something about terminal lucidity some time ago: viewtopic.php?p=12200#p12200

[Jim Cross]

This picture shows the brain at the advanced stage of Alzheimer's, basically about half of the brain volume and cells are gone. How can a person in a vegetative state with so much brain damage can possibly return to perfectly lucid state in full mental capacity (asking materialists of course)?

OTH, how do idealists explain Alzheimer's disease?

Science is still struggling to explain it but oddly terminal lucidity could point the way to treatments.

Case report notions of unexpected memory retrieval in patients with severe dementia near to death are starting to alter the central "irreversible" paradigm of dementia and locate dementia as a problem of memory retrieval, not consolidation. We suggest that the most likely central tenet of this paradoxical memory retrieval is the fluctuation of neuromodulators projecting from the brain stem to the medial prefrontal cortex and the hippocampus. The neuromodulation-centric explanation of this phenomenon aims to open the "irreversible" paradigm of dementia up for discussion and suggest a plausible treatment strategy by questioning how the devastating process of death fluctuates memory performance in severe dementia.

https://pubmed.ncbi.nlm.nih.gov/33064369/

Apparently during dying, serotonin from the brainstem floods the brain.

Death and dying are central events in the live of an organism, but neurobiological changes during this process are still rarely understood. Extracellular levels of serotonin, one of the phylogenetically oldest neurotransmitters, were measured continuously during dying. Serotonin levels increased threefold, while the EEG recorded simultaneously went down to a zero-line of no activity. This could be caused by the neuroprotective activity of brain serotonergic system, which subjectively makes dying easier due to the mood enhancing function of this neurotransmitter.

https://www.sciencedirect.com/science/a ... 4011005234

My take on it is that the memories of Alzheimer's patients are not lost but are unable to be retrieved. A flood of neuromodulators at near death can activate sufficient neurons to make some memories retrievable.

There isn't any straightforward equation between brain volume, number of neurons, and mental capability. People with smaller brains can sometimes outperform people with larger brains on mental tests. People with half their brain removed can function normally.

"The people with hemispherectomies that we studied were remarkably high-functioning," study author Dorit Kliemann said in a statement. "They have intact language skills. When I put them in the [brain] scanner, we made small talk, just like the hundreds of other individuals I have scanned," she explained.

https://www.webmd.com/brain/news/201911 ... ened-after

[Eugene I]

People with half their brain removed can function normally.

Well, yes, there is a fact that severe brain damage up to the removal of half of the sometimes does not lead to the cognitive disfunction. This is just another unexplainable fact. So what you are doing is referring the unexplainable fact of terminal lucidity to another unexplainable fact "People with half their brain removed can function normally." But that does not explain anything

The explanation that just an inflow of serotonin can restore the functioning of the damaged brain by Alzheimer's disease raises another question: why the body makes such an inflow and for what purpose? To make the experience of death more pleasant? But if that would be the case, how would such mechanism be rewarded evolutionary in order to be encoded in the genes and passed to the next generations? This would only be possible if old people who have pleasant experiences right before death could reproduce more successfully at this pre-death period, which of course is not possible.

[Jim Cross]

People with half their brain removed can function normally.

Well, yes, there is a fact that severe brain damage up to the removal of half of the sometimes does not lead to the cognitive disfunction. This is just another unexplainable fact. So what you are doing is referring the unexplainable fact of terminal lucidity to another unexplainable fact "People with half their brain removed can function normally." But that does not explain anything

The explanation that just an inflow of serotonin can restore the functioning of the damaged brain by Alzheimer's disease raises another question: why the body makes such an inflow and for what purpose? To make the experience of death more pleasant? But if that would be the case, how would such mechanism be rewarded evolutionary in order to be encoded in the genes and passed to the next generations? This would only be possible if old people who have pleasant experiences right before death could reproduce more successfully at this pre-death period, which of course is not possible.

Eugene,

Within some limits, brain functioning is about how the brain works not how big it is. Bigger isn't always better. There is a great deal of redundancy in neuron capabilities and memory. Also, a great deal of plasticity. Neurons perform multiple functions and can change functions. I think on a previous post I cited some studies showing how brain activity changes in the same person doing the same task over time. The brain isn't like a machine.

Regarding serotonin, the theory is that it is coming from the brainstem. The brainstem directly controls life support function like heartbeat and respiration. It wouldn't be surprising that the brainstem might go into some sort of uncontrolled firing when feedback from the life support systems is compromised or ceases. It might also be neuroprotective in cases of hypoxia if we are looking for an explanation how it came about. Serotonin by the way goes back to single cell organisms in the evolution.

[Eugene I]

Well, I guess we need to see if the effect of the Alzheimer's patients reverting to full mental capacity by only an inflow of serotonin into the brain stem could be reproduced in the lab.

[Jim Cross]

Well, I guess we need to see if the effect of the Alzheimer's patients reverting to full mental capacity by only an inflow of serotonin into the brain stem could be reproduced in the lab.

I think there are people looking into that.

Alzheimer's is still a complicated disease and there is still cell loss which will take its toll. So pumping up the serotonin, if that is possible, might only produce a short term fix and not a reversal of the disease itself. This would be much like L-DOPA and encephalitis_lethargica discussed in Oliver Sacks book Awakenings.



https://en.wikipedia.org/wiki/Encephalitis_lethargica

[Jim Cross]

I still haven't seen anybody try to explain Alzheimer's with idealism.

Why does mental functioning deteriorate in some people with aging? Does the universal mind also deteriorate? Why wouldn't it? If it doesn't what is happening to the individual mind (alter)?

Why does the mental functioning deteriorate in some people and not others?

If memories can be lost, where do they go? Could all of memories vanish with death?

This is all straightforward with an explanation that your mental activities are generated by the brain. In idealism, the brain is just the extrinsic image of the mind so what is happening under the covers in Alzheimer's disease? Is the mind under the extrinsic image deteriorating too?

[Eugene I]

May be you can ask BK in his blog