Neuroscience literature contains many myths, some of them concerning particular individuals. One myth is that patient HM had a hippocampus injury which prevented him from forming any new memories. The myth is debunked in my post here. Another myth is the myth that brain surgeon Wilder Penfield did something to show that memories are stored in brains.
Having someone merely recall some memory while a brain is being electrically stimulated would do nothing to show that memories are stored in brains. Human recall of old memories occurs all the time. So if you zap my brain, and I happen to recall at the time a pleasant day at the beach, that does nothing to show that my memory of that day is stored in my brain. But you might support the idea of brain storage of memories if there was a repeatable effect in which some stimulation of some tiny part of the brain always produced a recall of the same memory. Nothing like this was shown by the work of Wilder Penfield.
At www.archive.org I was able to find and borrow a 1967 book by Wilder Penfield, the book "The Excitable Cortex in Conscious Man." In that book Penfield discusses his research electrically stimulating parts of human brains. He makes no claim that a specific memory could be reproduced multiple times by stimulating a particular part of the brain. Instead on page 23 he merely refers to "experiential hallucinations" being produced by such brain stimulation.
We have no examples in Penfield's text of the same memory being produced by repeated stimulations of the same brain region. Below are some examples of what he reports.
On page 25 a T.S. being electrically stimulated at one part of his brain mentions "I feel as though I were in the bathroom at school," but later upon being stimulated "near the same point" says something about a street corner. Then when "the stimulation is repeated" the "response was quite different" because the man recalls a song from a popular musical.
On pages 28-30 we have an account of a patient (M.M) having her brain electrically stimulated at various places. The woman says something pretty vague about hearing voices:
"This was an incident of childhood, which she never have recalled without the aid of the stimulating electrode. Actually she could not 'remember' it but she knew at once, with no suggestion from us, that she must have experienced it sometime."
No evidence has been given that a real childhood memory has been recalled. Penfield has incorrectly stated that this MM "knew at once ...that she must have experienced it sometime," when the truth is that the woman merely said in a vague and hesitant way that "it seemed to be something that happened years ago," as if she was speculating.
Also on page 29 we have this:
Again, Penfield does some unjustified jumping-to-conclusions. He states that these vague narratives were "re-enactments of experiences," even though no good evidence has been provided of that. The subject MM has merely said in a hesitant manner that "it seems to be one I was visiting as a child." What could be going on is something like daydreaming or dreaming.
On page 30 we have more vague comments from MM after electrical stimulation of her brain, none of them sounding like a detailed recollection of something that actually happened. She reports seeing little things and hearing little things, and reports a feeling of familiarity. But at no time does it sound like a specific memory is being recalled. We hear no mention of specific person or specific places or specific times. Her comments are shown in red below:
On page 31 Penfield says without justification that "the psychical hallucinations, thus produced, were made up of experiences from this patient's past, not particularly important ones, and not ones she could voluntarily remember with anything like the clarity present during the hallucination." The statement does not seem to be justified by any of the patient statements cited, and the statements are very vague, varying and confused, without any of the hallmarks of a good memory recollection. We don't know whether any of M.M's statements at the moment of brain stimulation actually correspond to memories. And recollection of a memory while you are having part of your brain electrically stimulated would not prove that brains stored that memory, just as recalling something when you scratch your arm does nothing to prove that memories are stored in arms.
A 2017 review of 80 years of experiments on electrical stimulation of the brain uses the word “reminiscences” for accounts that may or may not be memory retrievals. The review tells us, “This remains a rare phenomenon with from 0.3% to 0.59% EBS [electrical brain stimulation] inducing reminiscences.” The review states the following:
"We observed a surprisingly large variety of reminiscences covering all aspects of declarative memory. However, most were poorly detailed and only a few were episodic. This result does not support theories of a highly stable and detailed memory, as initially postulated, and still widely believed as true by the general public....Overall, only one patient reported what appeared to be a clearly detailed episodic memory for which he spontaneously specified that he had never thought about it....Overall, these results do not support Penfield's idea of a highly stable memory that can be replayed randomly by EBS. Hence, results of EBS should not, at this stage, be taken as evidence for long-term episodic memories that can sometimes be retrieved."
A 1980 scientific paper by two University of Washington authorities states this about Penfield's brain zapping research:
"As we shall see, reports of 'memories' that occur
either spontaneously or as a result of memory
probes, such as electrical stimulation, hypnosis, or
psychotherapy, may not involve memories of actual past events at all. Rather, there is good reason to believe that such reports may result from
reconstruction of fragments of past experience
or from constructions created at the time of report that bear little or no resemblance to past
experience. Furthermore, secondary sources and
popular accounts tend to distort the evidence so
as to lend more credence to the notion of memory
permanence than is really warranted....Penfield began with 1,132
patients, and by his own admission, the patient
responses that might have indicated SL memory
recovery occurred in only 40 cases out of the total
of 1,132 cases surveyed, or only 3.5% of the time
(Penfield, 1969, p. 154)....When we eliminate the patients who heard only
music or voices and those whose responses were
too vague to classify, we find that less than 5%
of the patients contributed the lifelike experiential
responses for which Penfield's work is so famous.
And a detailed examination of even these patient
protocols leaves one with the distinct feeling that
they are reconstructions or inferences rather than
actual memories....In sum, Penfield would have us believe that
stimulation of the brain 'causes previous experience
to return to the mind of a conscious patient' and
that 'there is within the adult brain a remarkable
record of the stream of each individual's awareness or consciousness' (Penfield & Perot, 1963,
p. 692). But these conclusions (and the videorecorder model), based as they are on the dubious
protocols of a handful of patients, seem unwarranted.....These so-called memories, then, appear to consist merely of the thoughts and ideas that happened to exist just prior to and during the stimulation."
The 2022 paper here complains that "Penfield’s
elicitations of experiential phenomena are so rarely replicated in the modern era." It states this: "Curot et al. [6] concluded that this fragmentary nature of the experiential reports did not support
Penfield’s theory according to which patients were reliving a
complete experience of an event as if 'the sights and sounds
and thoughts of a former day' passed through his or her
mind again."
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