Whenever a person claims to have experienced something mystical or supernatural, the memory of that experience which enables them to make the claim is thoroughly material.
I remember that this thought came to mind while I was reading the "Memory" chapter in Matthew Cobb's fascinating book, The Idea of the Brain: The Past and Future of Neuroscience. (See here for my first post about the book.)
But that could be a false memory, though I don't believe it is, since I finished the chapter just a few days ago.
My wife, a retired psychotherapist, learned about false memories during a period in the United States, and maybe elsewhere also, when women, mostly, would recollect being sexually abused as a child in decidedly strange ways, such as at a Satanic ritual.
Eventually it became clear that false memories could be implanted in a person's brain when a counselor, say, would ask leading questions about being abused.
Since there is no way for us to tell if a memory is true or false other than comparing the recollection to some sort of objective standard, or perhaps by asking others who had the same experience, sometimes accusations against supposed child abusers were made that had no basis in fact.
This is very much in line with what Cobb writes about at the end of his "Memory" chapter, which I've shared below.
The definition of "engram" is: a hypothetical change in neural tissue postulated in order to account for persistence of memory. Here's an explanation of the reference to Penfield.
At the beginning of the chapter Cobb relates how, from the 1930s onwards, neurosurgeon Wilder Penfield carried out hundreds of brain operations in an attempt to relieve chronic debilitating temporal-lobe epilepsy.
He'd stimulate conscious patients with delicate electrodes to determine what part of the brain was a candidate for removal, if stimulating that part indicated a seizure was imminent.
This procedure revealed something rather eerie: sometimes the stimulation led the patient to relive very precise events. These experiences were vivid and detailed, like a waking dream.
... These strange sensations would occur only when the relevant area was being stimulated; if the electrode was removed, or if the patient was told that stimulation was occurring when it was not, nothing happened.
Now, here's how Cobb concludes the "Memory" chapter.
The research on the cellular basis of memory highlights what many psychological studies has previously demonstrated: memory is malleable. It is not simply a recording of ongoing events, it is constructed, and it can be false.
Above all, however, it has a material basis.
We have found elements of the engram, and it is not like memory on a hard disk in a computer. Biological memory is rich, unreliable and highly interconnected, with access to it taking place via multiple routes, not through a single address.
The link between our ordinary sense of how we remember things and precise memories that could be evoked by Penfield is not clear.
We do not appear to be perpetually recording our whole lives and yet those experiments reveal that highly specific and apparently inconsequential moments can be recalled, either by some external event, or by the pulse of an electrode.
The engram has given up a few of its most basic secrets, but we are still far from understanding what is happening when we remember.
Our brains might be like a computer in terms of how they sometimes process information, but the way we store and recall our memories is completely different. We are not machines -- or rather, we are not like any machine we have yet built or can currently envisage.
These advances in identifying the physical basis of memory raise the question of how sensory information -- the stuff of memory -- is processed by the brain in the first place.
Memories are held in particular sets of neurons, but that does not explain how the brain is able to work out what is in the world, and what exactly is being remembered.
The last paragraph is an introduction to the next chapter, "Circuits."