Our
neuroscientists have the bad habit of frequently spouting dogmas that
have not been established by observations. We have all heard these
dogmas stated hundreds of times, such as when neuroscientists claim
that memories are stored in brains, and that our minds are produced
by our brains. There are actually many observations and facts that contradict such dogmas, such as the fact that many people report
their minds and memories still working during a near death experience
in which their brains shut down electrically (as the brain does soon after
cardiac arrest).
One
of the most dramatic type of observations conflicting with
neuroscience dogmas is the fact that memory and intelligence is
well-preserved after the operation called hemispherectomy.
Hemispherectomy is the surgical removal of half of the brain. It is
performed on children who suffer from severe and frequent epileptic
seizures.
In
a scientific paper “Discrepancy Between Cerebral Structure and
Cognitive Functioning,” we are told that when half of their brains
are removed in these operations, “most patients, even adults, do
not seem to lose their long-term memory such as episodic
(autobiographic) memories.” The paper tells us that Dandy, Bell and
Karnosh “stated that their patient's memory seemed unimpaired after
hemispherectomy,” the removal of half of their brains. We are also
told that Vining and others “were surprised by the apparent
retention of memory after the removal of the left or the right
hemisphere of their patients.”
On page 59 of the book The Biological Mind, the author states the following:
A group of surgeons at Johns Hopkins Medical School performed fifty-eight hemispherectomy operations on children over a thirty-year period. "We were awed," they wrote later of their experiences, "by the apparent retention of memory after removal of half of the brain, either half, and by the retention of the child's personality and sense of humor."
In the paper "Neurocognitive outcome after pediatric epilepsy surgery" by Elisabeth M. S. Sherman, we have some discussion of the effects on children of temporal lobectomy (removal of the temporal lobe of the brain) and hemispherectomy, surgically removing half of the brain to stop seizures. We are told this:
After temporal lobectomy, children show few changes in verbal or nonverbal intelligence....Cognitive levels in many children do not appear to be altered significantly by hemispherectomy. Several researchers have also noted increases in the intellectual functioning of some children following this procedure....Explanations for the lack of decline in intellectual function following hemispherectomy have not been well elucidated.
Referring to a study by Gilliam, the paper states that of 21 children who had parts of their brains removed to treat epilepsy, including 10 who had surgery to remove part of the frontal lobe, "none of the patients with extra-temporal resections had reductions in IQ post-operatively," and that two of the children with frontal lobe resections had "an increase in IQ greater than 10 points following surgery."
The paper here gives precise before and after IQ scores for more than 50 children who had half of their brains removed in a hemispherectomy operation in the United States. For one set of 31 patients, the IQ went down by an average of only 5 points. For another set of 15 patients, the IQ went down less than 1 point. For another set of 7 patients the IQ went up by 6 points.
The paper here (in Figure 4) describes IQ outcomes for 41 children who had half of their brains removed in hemispherectomy operations in Freiburg, Germany. For the vast majority of children, the IQ was about the same after the operation. The number of children who had increased IQs after the operation was greater than the number who had decreased IQs.
Referring to these kind of surgeries to remove huge amounts of brain tissue, the paper “Verbal memory after epilepsy surgery in childhood” states, “Group-wise, average normed scores on verbal memory tests were higher after epilepsy surgery than before, corroborating earlier reports.”
Some
try to explain these results as some kind of special ability of the
child brain to recover. But there are similar results even for adult
patients. The page here mentions 41 adult patients who had a
hemispherectomy. It says, “Forty-one patients underwent additional
formal IQ testing postsurgery, and the investigators observed overall
stability or improvement in these patients,” and notes that
“significant functional impairment has been rare.”
Of
these cases of successful hemispherectomy, perhaps none is more astonishing
than a case of a boy named Alex who did not start speaking until the
left half of his brain was removed. A scientific paper describing
the case says that Alex “failed to develop speech throughout early
boyhood.” He could apparently say only one word (“mumma”)
before his operation to cure epilepsy seizures. But then following a
hemispherectomy (also called a hemidecortication) in which half of his brain was removed at age 8.5, “and withdrawal of
anticonvulsants when he was more than 9 years old, Alex suddenly
began to acquire speech.” We are told, “His most recent scores on
tests of receptive and expressive language place him at an age
equivalent of 8–10 years,” and that by age 10 he could “converse
with copious and appropriate speech, involving some fairly long
words.” Astonishingly, the boy who could not speak with a full
brain could speak well after half of his brain was removed. The
half of the brain removed was the left half – the very half that
scientists tell us is the half that has more to do with language than
the right half.
Cases
like this make a mockery of scientist claims to understand the human
brain. When scientists discuss scientific knowledge relating to
memory, they almost never discuss the most relevant thing they could
discuss, the cases of high brain function after hemispherectomy operations in which half of the brain is removed. Instead
the scientists cherry-pick information, and describe a few experiments and
facts carefully selected to support their dogmas, such as the dogma that brains store memories, and brains make minds. They also fail to
discuss the extremely relevant research of John Lorber, who
documented many cases of high-functioning humans who had lost almost
all of their brain due to hydroencephaly.
A
scientist discussing memory will typically refer us to experiments
involving rodents. Such experiments are almost always studies with
low statistical power, because the experimenter failed to use at
least 15 animals per study group, the minimum needed for a moderately
reliable result with a low risk of a false alarm. There will be
typically be some graph showing some measurement of what is called
freezing behavior, when a rodent stops moving. The experimenter will
claim that this shows something was going on in regard to memory,
although it probably does not show such a thing, because all
measurements of a rodent's degree of freezing are subjective
judgments in which an experimenter's bias might have influenced
things. There will often be claims that a fear memory was regenerated
by electrically zapping some part of the brain where the experimenter
thought the memory was stored. Such claims have little force because
it is known that there are many parts of a rodent's brain that will
cause a rodent to stop moving when such parts are electrically
stimulated. And, of course, rodent experiments prove nothing about
human memory, because humans are not rodents.
When
a scientist discusses memory research, he will typically discuss the
case of patient HM, a patient who was bad at forming new memories
after damage to the tiny brain region called the hippocampus. Again
and again, writers will speak as if this proves the hippocampus is
crucial to memory. It certainly does not. The same very rare effect
of having a problem in forming new memories cropped up (as reported here) in a man who
underwent a dental operation (a root canal). The man had no brain
damage, but after the root canal he was reportedly unable to form new
memories. Such cases are baffling, and the fact that they can come
up with or without brain damage tells us no clear tale about whether
the hippocampus is crucial for memory. The hemispherectomy cases
suggest that the hippocampus is not crucial for memory, for each
patient who had a hemispherectomy lost one of their two
hippocampuses, and overall there was little permanent effect on the
ability to form new memories.
A
scientific paper tells us that “lesions of the rodent hippocampus
do not produce reliable anterograde amnesia for context fear,”
meaning rodents with a damaged hippocampus can still produce new
memories. The paper also tells us, “These data suggest that the
hippocampus is normally involved in context conditioning but is not
necessary for learning to occur.” So it seems that the main claim
that neuroscientists cite to persuade us that they have some
understanding of a neural basis for memory (the claim that the
hippocampus is “crucial” for memory) is really a factoid that is
not actually well established.
Postscript: The case of patient HM has been cited innumerable times by those eager to suggest that memories are brain based. Such persons usually tell us that patient HM was someone unable to form any new memories. But a 14-year follow-up study of patient HM (whose memory problems started in 1953) actually tells us that HM was able to form some new memories. The study says this on page 217:
In February 1968, when shown the head on a Kennedy half-dollar, he said, correctly, that the person portrayed on the coin was President Kennedy. When asked him whether President Kennedy was dead or alive, and he answered, without hesitation, that Kennedy had been assassinated...In a similar way, he recalled various other public events, such as the death of Pope John (soon after the event), and recognized the name of one of the astronauts, but his performance in these respects was quite variable.
The study also says that patient HM was able to learn a maze (although learning it only very slowly), and was able eventually to walk the maze three times in a row without error.
Postscript: The case of patient HM has been cited innumerable times by those eager to suggest that memories are brain based. Such persons usually tell us that patient HM was someone unable to form any new memories. But a 14-year follow-up study of patient HM (whose memory problems started in 1953) actually tells us that HM was able to form some new memories. The study says this on page 217:
In February 1968, when shown the head on a Kennedy half-dollar, he said, correctly, that the person portrayed on the coin was President Kennedy. When asked him whether President Kennedy was dead or alive, and he answered, without hesitation, that Kennedy had been assassinated...In a similar way, he recalled various other public events, such as the death of Pope John (soon after the event), and recognized the name of one of the astronauts, but his performance in these respects was quite variable.
The study also says that patient HM was able to learn a maze (although learning it only very slowly), and was able eventually to walk the maze three times in a row without error.
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