Just Call Them "Machine-Metaphor-Misguided"

A recent interview on the website www.vox.com inadvertently gives us a portrait of the scrambled thinking of modern neuroscientists, whose thinking about the brain is senselessly guided not by the low-level characteristics of the brain discovered by neuroscientists, but by silly mechanical metaphors in which the non-mechanical brain is constantly compared to machines invented by men.  The article containing the interview begins with the statement, "It’s difficult to talk about the human brain without inadvertently talking about computers."  No, that isn't true. 

The interview is with a zoologist named Matthew Cobb, who has written about the history of ideas about the brain.  Cobb had some insightful and intelligent-sounding things to say about the improbability of eukaryotic cells evolving, which I quoted in a 2017 post.  But in this interview his answers are empty-sounding. 

Cobb makes it sound like scientists have a history of comparing the brain to whatever is the most impressive communications technology available in a particular time. So when the telegraph was the latest and greatest in communication technology (around 1850), the brain was compared to a telegraph; and when telephone technology was the latest and greatest in communication technology (in the early twentieth century), the brain was compared to a telephone switchboard; and when computers and Internet-capable devices were the latest and greatest in communications technology, the brain was compared to a computer. 

None of these metaphors ever made sense. Telegraph systems, telephone systems and computer systems all are based on the signal transmission in copper wires that transmit signals with near-100% reliability.  The chemical synapses in the brain that are by far the most common type of synapses have no such reliability. Tests have shown that in a chemical synapse the probability of successful transmission is less than 50%. 

In an interview, an expert on neuron noise states the following:

"There is, for example, unreliable synaptic transmission. This is something that an engineer would not normally build into a system. When one neuron is active, and a signal runs down the axon, that signal is not guaranteed to actually reach the next neuron. It makes it across the synapse with a probability like one half, or even less. This introduces a lot of noise into the system."

So according to this expert, synapses (the supposed storage place of human memories) transmit signals with a probability of less than 50 percent. That's very heavy noise – the kind of noise you would have if half of the characters in your text messages got scrambled by your cell phone carrier.  A scientific paper tells us the same thing. It states, "Several recent studies have documented the unreliability of central nervous system synapses: typically, a postsynaptic response is produced less than half of the time when a presynaptic nerve impulse arrives at a synapse." Another scientific paper says, "In the cortex, individual synapses seem to be extremely unreliable: the probability of transmitter release in response to a single action potential can be as low as 0.1 or lower."

Another reason it never made sense to compare the brain to a telegraph system is that telegraph systems are based on a particular signal transmission code (the Morse Code) invented by Samuel Morse; but no one has ever discovered any evidence of any code system in the brain by which complex learned information can be reliably transmitted or stored or retrieved.  No one has ever discovered a "brain code" or a "neuron code" analagous to the Morse Code.  

It also never made any sense to compare the brain to a telephone switchboard. In an old-fashioned telephone switchboard, a caller would be routed exclusively to one particular telephone number.  For example, a switchboard operator (after getting a request) might cause the caller with the number 342-2352 to be exclusively routed so that one and one phone number would ring: the number 342-4252.   But the brain does not work like that. Most neurons are connected to very many other neurons.  A scientific paper tells us, "Each neuron may be connected to up to 10,000 other neurons, passing signals to each other via as many as 1,000 trillion synapses."

This is actually an extremely strong reason for rejecting all claims that memory recall occurs in brains or that memories are stored in brains or that brains produce thinking.  In my long post here I discuss this point at great length.  I'll give just a short summary of my reasoning: reliable signal transmission only occurs when there is an exclusive or near-exclusive relation between a receiver and a transmission source. That's why TV sets never receive ten channels at the same time. When a receiver is bombarded by signals from very many sources at the same time, it would be like a TV that is simultaneously getting broadcasts from very many TV channels. The result would be an unintelligible jumble kind of like the mess shown in the visual below:

A jumble rather like the one above is something we should expect from a brain in which each neuron is always getting signals from very many other neurons, except that the jumble and unintelligibilty would be far worse; for most neurons receive signals from very many other neurons. 

But what about the modern-day "brain as computer" metaphor? It never made any sense. To understand why, just read my post entitled "The Brain Has Nothing Like 7 Things a Computer Uses to Store and Retrieve Information." Below are the things I mentioned, things that are crucial components of computers, but have no counterpart in the brain:

• An Operating System
• An Application to Store and Retrieve Data
• The ASCII Code for Encoding Information
• A Decimal to Binary Conversion Table or Utility
• A Medium That Allows a Permanent, Stable Storage of Information
• A Storage Location System by Which the Exact Position of a Data Item Can be Specified, Allowing Fast Retrieval from an Exact Location
• Read/Write Functionality Allowing Data to Be Written to a Specific Location and Also Read From the Same Location

Asked about when scientists first started assuming that thinking comes from the brain, we get a very revealing answer from Cobb, an answer that inadvertently reveals the lack of any sound foundation for such an idea.  The answer is a minor classic of empty  insubstantiality. Here is Cobb's answer about when scientists first started assuming that thinking comes from the brain:

"Not in one moment. You mustn’t get the idea that somebody suddenly did an experiment and said, 'Aha!' Instead, there’s this slow accumulation of certainty. First, there’s anatomical demonstration that the 'viscera' like the heart have other functions. The heart is a pump, which was demonstrated at the beginning of the 17th century — so it doesn’t have the wherewithal to do the mysterious business associated with perception and thinking and so on. On the other hand, the brain, as anatomical studies showed, has got all these neurons, and it’s connected by the neurons to all the sense organs and everything else. So gradually, in the course of the 17th century in particular, people became increasingly confident that it was the brain that was doing thinking. How it did it, they weren’t quite sure."

Cobb confesses that there was never any experiment that caused scientists to assume that brains think.  He suggests that showing that hearts probably don't think was some reason for thinking that brains think, which makes no sense at all. You do not show that one organ does something by showing that some other organ does not do that thing.  The fact that neurons are connected to sense organs does nothing to show that brains cause thinking.  The phrase "slow accumulation of certainty" is very misleading. There has never been any certainty that brains think, nor any sound basis for believing that they do think.  

To the contrary, there are the strongest reasons for thinking that brains cannot possibly be the cause of lightning-fast human thinking. They include the following:

• The fact that no one has the slightest idea of how any arrangement of neurons could ever cause the arising of abstract ideas. Cobb's claim that neuroscientists aren't quite sure of how a brain could think is misleading. The truth is they haven't the slightest credible idea of how such a thing could occur.  
• The fact that severe slowing factors should make it impossible for brains to produce the lightning fast thinking that occurs in people such as math savants who can produce very complex calculations with astonishing speed. 
• The fact that unreliable synaptic transmission (discussed above) should make accurate memory recall and very accurate thinking impossible, contrary to the reality that humans such as Hamlet actors can recall large bodies of text with perfect accuracy, and other humans can do very complex mental calculations "in their head" with perfect accuracy.

An extremely important point about human thinking is that some people are capable of doing very complex thinking with blazing speed and perfect accuracy.  The natural limitations of the brain (very heavy signal noise, many internal slowing factors, and unreliable synapse transmission) rule out the brain as a source of such phenomena. An example of such a person is Neelakantha Bhanu Prakash, called "the world's fastest calculator." He can do things such as accurately multiply 869,463,853 times 73 in just 20 seconds. This is despite the fact that he had a very bad brain injury in a motorcycle crash, an injury to the front of his head so bad it required 85 stitches, multiple operations and a medically induced coma to treat.  He still has a prominent scar on his forehead as a reminder of the accident. 

Later in the interview discussed above, Cobb makes this very misleading statement comparing brain wiring to undersea transatlantic cables:

"They looked, for example, at the structure of undersea cables that were carrying telegraph messages across the Atlantic, and they could see that there was a central core of copper and then around it was insulation. And then they looked at neurons, at nerves, and they said, 'Well, this is exactly the same.' " 

Many readers probably read that statement and thought: "Gee, I didn't know there are copper wires inside the brain." There are no such things. There are what are called myelinated axons in the brain that transmit signals quickly. But in the grey matter cortex of the brain the great majority of axons are not well myelinated. A scientific text co-written by a Yale scientist says this:

"The axons of grey matter are not heavily myelinated, unlike white matter, which contains a high concentration of myelin. The grey matter contains the majority of neuron somas, making it appear tan with circulation but grey when prepared for examination outside of the body. These somas are circular structures that house the nucleus of the cells."

Besides the lack of myelination in the grey matter of the brain, there's a crucial reason why the "transatlantic cable" analogy is profoundly misleading. The 1866 transatlantic cable was capable of transmitting eight words per minute across the Atlantic ocean, because of a lack of any "speed bumps" that would slow down the signal. In the cortex there are "speed bumps" all over the place.  They include the following:

(1) The speed of transmission through dendrites, which can be 200 or more times slower than the "100 meters per second" estimate based on transmission through well-myelinated axons. According to one expert, dendrites make up 90% of neural tissue. 
(2) Synaptic delays, each about .5 millisecond, which end up being a huge slowing factor because so very many synapses must be traversed to pass through a decent amount of cortex tissue.
(3) Synaptic unreliability or noise, the fact that a signal across a synapse is typically transmitted with only between 10% to 50% likelihood, a factor that is typically ignored but which has a huge impact on effective speed.
(4) Synaptic fatigue, the fact that a synapse will so often need a rest period after firing, a period that can be more than a minute.
(5) Tortuosity, the fact that nerve signals must travel through sinuous paths that are not straight lines.
(6) Folding of cortex tissue, a further slowing factor. 

(7) Low myelination in the cortex, where the gray matter has little myelination. 

Every one of these factors is ignored by 95% of discussions of brain signal speed in the popular press. Altogether these factors should cause us to conclude that the brain cannot possibly be the source of very fast recall and very fast thinking in people such as mathematical savants. 

After discussing how brains were first compared to telegraph systems and then compared to telephone systems, Cobb is asked "what came after the telephone?" He describes the latest silly machine metaphor, whose silliness he fails to perceive:

"Well, the dominant metaphor is that the brain is something like a computer. It’s carrying out some kind of calculations. And that idea, which came into being in the 1940s and early 1950s, still dominates over 70 years on." 

To see why this metaphor makes no sense, read my post entitled "The Brain Has Nothing Like 7 Things a Computer Uses to Store and Retrieve Information."  Among the reasons why it is senseless to claim that brains make minds and brains are like computers, some additional reasons are:

• Minds are conscious, and computers are not.
• Minds can have novel abstract ideas, and computers cannot. 
• Minds can have curiosity and morality, but computers cannot. 
• Minds have experience and feelings, and computers do not. 
• Minds can be interested in things, but computers cannot. 
• Minds can experience pleasure and pain, but computers cannot.

A very general question that we should be asking again and again to scientists is: "What forced you to believe that?" When there is a good evidence basis for thinking something, scientists will be able to discuss some evidence that forced them to believe some particular thing, regardless of whether they wanted to.  There is nothing at all that forced scientists to believe that brains produce thinking. They simply adopted such a belief because they didn't want to believe in souls or because they wanted to say they had an answer to a deep question they did not understand.  The lack of any good evidence  basis for believing that brains produce thinking is suggested by the very wobbly "not in one moment" answer given by Cobb quoted above. 

Neuroscientists should not be asking, "What machine created by humans should we compare the brain to?" Instead, neuroscientists should be asking, "What low-level facts that we have learned about the brain should cause us to reduce and limit our ideas about what the brain could be capable of?" Above I have listed many such facts, senselessly ignored by neuroscientists.  There are many other such facts mentioned in other posts on this blog. 

Seeing Only Synaptic Instability and Variability, They Misleadingly Call It "Synaptic Plasticity"

 Some of the terms most often used by biologists are misleading terms. Perhaps the biggest example is the term "natural selection." Selection is a term meaning a choice by a conscious agent. The so-called "natural selection" imagined by those who use such a term does not actually involve any selection or choice.  The "natural selection" imagined by biologists merely involves a survival-of-the-fittest effect, in which fitter organisms survive longer or reproduce more. The duplicity of using the term "natural selection" for some imagined effect that is not actually selection is a word trick that was started by Charles Darwin, who coined the term "natural selection."

Then there is the term "body plan." To the average person this sounds like a plan for building the body of an organism. But biologists routinely use the term "body plan" to mean something much, much less: merely the features common to all the organisms that make up a phylum. According to such a definition, all species in the Chordata phylum (including humans, bears, dogs and fish) have the same body plan, which consists of little more than a backbone and a tendency towards bilateral symmetry (having the same features on the left and right side). With such a definition of "body plan," biologists can make very misleading statements that fool us into thinking they know far more than they do.  Biologists may say that they know how humans got their body plan,  and by "body plan" mean little more than a backbone-based body structure.  90% of the people hearing such a boast about a body plan will misunderstand, and think that such biologists are claiming that they know how the incredibly organized human structure arises from a vastly less organized speck-sized egg (something biologists do not actually know, largely because DNA does not specify anatomy). 

Then there is the term "long-term potentiation." What is misleadingly called “long-term potentiation” or LTP is a not-very-long-lasting effect by which certain types of high-frequency stimulation (such as stimulation by electrodes) produces an increase in synaptic strength.  The problem is that so-called long-term potentiation is actually a very short-term phenomenon. A 2013 paper states that so-called long-term potentiation is really very short-lived:

"LTP always decays and usually does so rapidly. Its rate of decay is measured in hours or days (for review, see Abraham 2003). Even with extended 'training,' a decay to baseline levels is observed within days to a week."

So-called long-term potentiation is no more long-term than a suntan. The use of the term "long-term potentiation" for such an effect is deceptive, particularly when it is suggested that so-called "long-term potentiation" might have something to do with explaining memories that can last for 50 years or longer. 

Another very misleading term used by biologists is the term "synaptic plasticity."  To explain why the term is misleading, let me look at what has been observed regarding synapses and dendritic spines: something that is merely instability and high variability. 

As a general rule, individual synapses are too small to be well-observed in large numbers by scientific equipment.  By using equipment such as electron microscopes, scientists can zoom in on one or a few synapses. But with so many billions of synapses in the brain it is effectively impossible to reliably determine whether synapses are responding to some sensory input or learning experience. Easier than observing individual synapses is the task of observing what are called dendritic spines. Dendritic spines are little bumps on dendrites. In the visual below, the bottom part shows a closeup of the tiny red circle in the top part. 

The dendritic spines have a close relation to synapses, because synapses are typically found clustered around such dendritic spines. 

What do scientists see when observing such dendritic spines? They see them very slowly appearing and disappearing, and very slowly randomly changing in size. Dendritic spines are rather like pimples on the face of a teenager with acne, pimples that slowly come and go, increasing or decreasing in size. The correct word to describe such constant changes in all dendritic spines is variability, not plasticity. There is no evidence of such dendritic spines changing in some systematic way, some kind of way suggesting information storage.  There is no robust evidence that any dendritic spines have ever changed in some way that correlates with learning or memory formation. 

There are two terms in the English language that correctly describe what we observe in dendritic spines and synapses. The words are "instability" and "variability."  But neuroscientists don't like to use those words when talking about synapses. Instead, they prefer to use the term "synaptic plasticity." Such a term is very misleading. 

When I do a Google search for "plasticity definition," the first result I get gives me a definition of "the quality of being easily shaped or modified."  The Merriam-Webster online dictionary gives two definitions of "plasticity":

1. The quality or state of being plastic especially: capacity for being molded or altered.

2. The ability to retain a shape attained by pressure deformation.

It is rather clear what the intention was when scientists first started using the term "synaptic plasticity."  The intention was to bring to mind the idea of synapses being like clay in which memories can be written. Used by the Babylonians who used cuneiform, writing in clay was one of the oldest methods used by humans to record information. Clay had two great advantages: (1) a person using a metal stylus could instantly write letters on clay; (2) clay could permanently store letters written on it. 

There are two reasons why it is very misleading to be using the term "synaptic plasticity." The first is that no one has ever observed any effect in which synapses quickly take on some particular shape or pattern in response to some causal factor. Nothing like any molding or shaping effect has ever been observed. 

The second reason is that term "plasticity" implies the retention of some pattern that was produced by a shaping or molding effect. The second Merriam-Webster definition of plasticity is "the ability to retain a shape attained by pressure deformation."  What we observe in dendritic spines and synapses is such a high level of variability and instability that there is every reason to doubt that they could be capable of retaining any pattern if such a pattern were ever to be impressed on them. 

Dendritic spines last no more than a few months in the hippocampus, and less than two years in the cortex. This study found that dendritic spines in the hippocampus last for only about 30 days. This study found that dendritic spines in the hippocampus have a turnover of about 40% each 4 days. This study found that dendritic spines in the cortex of mice brains have a half-life of only 120 days. The wikipedia article on dendritic spines says, "Spine number is very variable and spines come and go; in a matter of hours, 10-20% of spines can spontaneously appear or disappear on the pyramidal cells of the cerebral cortex." Referring to in vivo observations of dendritic spines in the mouse hippocampus, the paper here says the authors "measured a spine turnover of ~40% within 4 days."  The 2017 paper here ("Long-term in vivo imaging of experience-dependent synaptic plasticity in adult cortex") found the following regarding dendritic spines in the cortex of rodents:

"About 80% of synapses were detectable for a day or longer; about 60% belonged to the stable pool imaged for at least 8 days. Even this stable pool was found to turn over, with only, 50% of spines surviving for 30 days or longer. Assuming stochastic behaviour, we estimate that the mean lifetime of the stable pool would be on the order of 120 days."

The paper here states, "Experiments indicate in absence of activity average life times ranging from minutes for immature synapses to two months for mature ones with large weights."

We have no good evidence that any dendritic spines survive for more than  a few years. There is an often-cited paper from the year 2000 with the title "Stably maintained dendritic spines are associated with lifelong memories." The title is misleading, like the title of so many scientific papers.  The paper actually found that "a tiny fraction of daily formed new spines (~0.2% of the total spines) could persist for 3–5 months." So the paper found that only 1 in 500 dendritic spines persist for as long as 5 months.  The paper resorts to some dubious math to try to hypothesize that some dendritic spines may last for years. 

More recent papers have made even more clear the high turnover rate of dendritic spines, and have made it seem less likely that any dendritic spines survive for more than a few years.  The 2015 paper 

"Impermanence of dendritic spines in live adult CA1 hippocampus" states the following, describing a 100% turnover of dendritic spines within six weeks:

"Mathematical modeling revealed that the data best matched kinetic models with a single population of spines of mean lifetime ~1–2 weeks. This implies ~100% turnover in ~2–3 times this interval, a near full erasure of the synaptic connectivity pattern."

The paper here states, "It has been shown that in the hippocampus in vivo, within a month the rate of spine turnover approaches 100% (Attardo et al., 2015; Pfeiffer et al., 2018)." The 2020 paper here states, "Only a tiny fraction of new spines (0.04% of total spines) survive the first few weeks in synaptic circuits and are stably maintained later in life."  The author here is telling us that only 1 in 2500 dendritic spines survive more than a few weeks.  Given such an assertion, we should be very skeptical about the author's insinuation that some very tiny fraction of such spines "are stably maintained." No one has ever observed a dendritic spine lasting for years, and the observations that have been made of dendritic spines give us every reason to assume that dendritic spines do not ever last for more than a few years. 

The same studies that show such short lifetimes for dendritic spines show that while they exist, dendritic spines very rarely maintain the same size and shape.  During their short lifetimes, dendritic spines tend to change very much in size and shape.  

So dendritic spines and synapses are unstable and highly variable things, and there is no evidence that they can retain some pattern that might be impressed on them. There is no evidence that dendritic spines or synapses quickly change in respond to something an organism has learned or experienced.  There is zero robust evidence of any kind of code used by which information is imprinted on dendritic spines or synapses. We know that the proteins in such dendritic spines and synapses are very short-lived, having average lifetimes of less than two weeks. While we can honestly refer to synaptic instability and synaptic variability, we have no observational warrant for using the phrase "synaptic plasticity." 

This confusion in which mere variability is incorrectly described as plasticity is shown in the Wikipedia.org article on dendritic spines, where we read this:  "Dendritic spines are very 'plastic', that is, spines change significantly in shape, volume, and number in small time courses." Such random changes will be seen in any group of dendritic spines observed, and they are correctly described as "variability" rather than "plasticity."  Rather than stating that dendritic spines or synapses are "plastic" (a claim for which there is no robust evidence), we should merely be saying that dendritic spines and synapses are variable and unstable.  We have good evidence that dendritic spines are constantly undergoing random changes. We have no good evidence that such changes are any type of "plasticity" shaping or molding effect produced by sensory experience or learning. 

What often goes on in neuroscience literature is a very careless confusion between variability and plasticity.  Variability refers to something that undergoes random changes. Plasticity refers to some effect in which something molds or shapes in response to the action of something acting like a molder or shaper.  We have lots of evidence for the constant variability of synapses and dendritic spines. We have no good evidence for plasticity occurring in such things. Similarly, we have very good evidence for variability in the sky above our heads, which constantly undergoes changes as different clouds drift by. We have no evidence for plasticity in the sky above our heads.  

There have been studies that have claimed to provide evidence for synaptic plasticity in the sense of synapses changing in response to some experience, but such studies have provided no actual robust evidence backing up such claims.  In a typical study of this type some animal will be given some sensory experience or learning experience, and then some dendritic spines or synapses will be watched.  The paper may claim that some increases in dendritic spines or synapses were  observed, and that this is evidence that such things were responding to the sensory experience or learning experience.  The flaw in such reasoning is obvious. Since a mouse has something like a trillion synapses and very many billions of dendritic spines, which tend to undergo random changes,  there is no reason to think that some small group of dendritic spines or synapses chosen for study would be exactly the right dendritic spines or synapses that might be responding to some sensory input or learning experience. It would be far more likely that some dendritic spines or synapses chosen for study would have no connection at all to some sensory experience or learning experience, and that any change observed would be mere random variation. 

Part of the problem is the enormous number of synapses.  Humans have something like 100 trillion synapses, and  even mice have a trillion synapses. So it is impossible to do some experiment that observes something like a molding or shaping effect in which synapses take some particular shape or configuration in response to some sensory input or learning experience.  Even if you were to do some in vivo experiment in which you saw some synapses change just after a learning experience or sensory experience, you would have no way of knowing whether such a change was just a random change that would have occurred even if the learning experience or sensory experience had not occurred. 

Given a brain in which there are something like a trillion synapses and dendritic spines which are undergoing random changes, like pimples on the face of a teenager with acne, you absolutely do not show an effect of plasticity (synapses or dendritic spines changing in response to a learning or sensory experience) by showing that some small number of synapses or dendritic spines increased in size or strength after something was learned. We would expect that perhaps 25% of any randomly selected dendritic spines or synapses would increase after some learning occurred, even if this was in no way produced by learning or sensory experience. Similarly, if I claimed that stocks sometimes rise in response to what I write, I would provide no robust evidence for such a claim by showing that five or ten stocks had risen in value on some day I wrote something. At least a quarter of all stocks will increase in value on a random day.  

A 2021 scientific paper gives us a sentence of unproven dogma, followed by another sentence confessing the lack of observations to support such a dogma:

"A defining feature of the brain is the ability of its synaptic contacts to adapt structurally and functionally in an experience-dependent manner. In the human cortex, however, direct experimental evidence for coordinated structural and functional synaptic adaptation is currently lacking."

Or to put it more concisely, there's no good evidence for synaptic plasticity, in the sense of synapses molding in response to something learned or experienced. Scientists looking for evidence of memories forming in the brain are still empty-handed, although their misleading words often suggest otherwise.  Another recent paper kind of gives us a hint that "there's no there there" by saying at its beginning, "After decades of research on memory formation and retention, we are still searching for the definite concept and process behind neuroplasticity," which has a "still grasping for moonbeams" sound to it. 

He's Strangely Seeking Memories in Cells Below the Neck

Psychiatrist Thomas R. Verny has written a very interesting article entitled "Enduring Memory."  Below the title we read the line "How can animals whose brains have been drastically remodelled still recall their kin, their traumas and their skills?"

In the first sentence of the article Verny mentions a concept he calls "cellular memory," and which he defines as "the idea that memory can be stored outside the brain, in all the body’s cells."  This is an idea that is completely contrary to what our scientists have been teaching for many decades, that memories are stored in the brain.  The term "cellular memory" is a poor term for such a concept, since anyone hearing such a term would think of memory being stored in brain cells.  A better term for such an idea would be "below-the-neck cellular memory." 

Verny discusses some reasons for rejecting claims that memories are stored only in the brain. He mentions the case of a French civil servant who was found to have only a thin sheet of brain tissue, since almost all of his brain had been gradually replaced by a watery fluid.  He fails to give us a link to the original story, which can be read here. By following that link you can see photos that show how almost-empty the brain was of that person with an IQ of 75.  

Verney discussed other similar cases. He states, "Following hemispherectomy – where half the brain can be removed to control seizures – most children showed not only an improvement in their intellectual capacity and sociability but also their apparent retention of memory, personality and sense of humour."  By reading my post here, you can read many specifics about such cases, including papers giving IQ scores before and after removal of half of a brain, showing little change. The details given in that post back up the claim of Verney I just quoted. Verney fails to mention the cases documented by the physician John Lorber, who showed that quite a few patients with much less than half of a brain had above-average intelligence. 

Verney then makes a statement that makes no sense. He states, "If people who lack a large part of their brain can function normally, or even relatively normally, then there must exist, I thought, some kind of back-up system that can kick in when the primary system crashes."  The phrase he should have been using in such reasoning is  "half of their brain or most of their brain," since we know from hemispherectomy operations and hydrocephalus cases that people can function relatively normally when half or most of their brain is lost.  

There is no warrant from the cases discussed above for the idea that there exists some "back-up system" that "can kick in" when half or most of the brain is lost, replacing function that was previously carried out by the brain.  Instead, the evidence discussed above should cause us to conclude that the brain is not the source of our intellectual functions and is not the storage place of our memories. Such cases support the idea that human memory and human cognition are aspects of a human soul or spirit rather than products of the brain or any other physical part of the body.  Just as there is nothing in the brain that bears any resemblance to a system for storing and retrieving memories, there is nothing below the neck that bears any resemblance to a system for storing and retrieving memories. 

Without doing anything to substantiate his speculation about memories stored below the neck, Verny then goes into a discussion of evidence that animals can maintain memories despite massive brain damage.  He discusses evidence from planarian experiments, which I discussed in my post here. There is evidence that decapitated planarians can retain memories they have learned. Verny also mentions studies showing that animals can retain memories very well after hibernation, which causes large loss of brain cells. He also discusses evidence that caterpillars turning into butterflies can retain as butterflies things they learned as caterpillars, despite the almost total reorganization of the organism during metamorphosis. 

Failing to provide any evidence of memories being stored in any cells (either below the neck or above the neck), but merely evidence of organisms remembering things despite heavy brain damage, Verny concludes by stating this:

"It seems credible to conclude that memory, in addition to being stored in the brain, must also be encoded in other cells and tissues in the body. In other words, we are all endowed with both somatic and cognitive memory systems that mutually support each other. In aggregate, the evidence suggests that aspects of intelligence and consciousness traditionally attributed to the brain have another source as well. Our memories, our tastes, our life knowledge, might owe just as much to embodied cells and tissues using the same molecular mechanisms for memory as the brain itself. The mind, I conclude, is fluid and adaptable, embodied but not enskulled."

Other than facts suggesting the brain cannot be the source of human thinking and the storage place of human memories, there are no reasons to believe the idea of cognition and memory coming from cells below the neck. We know that a person can lose very many of his cells below the neck without any effect on cognition or memory. Specifically:

• A person will not lose any of his memories or cognitive abilities if he loses an arm, both arms, a leg or even both legs. 
• A very overweight person may gradually lose half of his weight through either dieting or food deprivation, but this will have no effect on his memories or cognitive abilities.
• A person may have a lung transplant, but this will have no effect on his memories or cognitive abilities. After getting such a transplant, he will not have some knowledge he did have before, that was learned by the person from whom the lung came. 
• A person may have a heart transplant, but this will have no effect on his memories or cognitive abilities. After getting such a transplant, he will not have some knowledge he did not have before, that was learned by the person from whom the heart came. 

Before 1800 no one ever lost half of their brain because of surgical operations. Hydrocephalus that damages the brain occurs in about 3 cases in 1000, but cases involving major brain damage are much more rare, involving fewer than 1 case in 1000.  It is hardly believable to assume that evolution would have provided some back-up cognitive system to deal with such rare cases. Believing such a thing would be like believing that some organism would evolve a parachute-like organ on its back, to cover the maybe 1 case in 1000 when organisms of that type might fall off a cliff.  We have no evidence in the natural world that organisms have systems that serve only to cover extremely rare unfortunate events. 

The posts on this blog discuss many reasons for disbelieving the claim that memories are stored in brains, and quite a few of these reasons would apply in equal force to claims of memories stored below the neck. I will give one example. One of the greatest wonders of the human mind is the wonder of instantaneous memory recall, such as occurs when you instantly provide information on a topic after hearing a single word or name.  For reasons discussed here, such a capability cannot be explained by neural action, because the brain is completely lacking in anything like an indexing system, a coordinate system, or a position notation system that would allow the exact position of some stored memory to be instantly found.  Exactly the same objection applies to the body below the neck, which is also completely lacking in anything like an indexing system, a coordinate system, or a position notation system.  And just as there is no evidence of anything in the brain that could write learned information or read learned information, there is no evidence of any such thing existing below the neck (except for hands that don't write inside the body).  

We have no evidence of memories being physically stored below the neck. We do have very much evidence that humans have something like souls.  A major part of this evidence is what occurs during out-of-body experiences, in which people (with not diminished minds and memories) report floating out of their bodies and observing their bodies from a higher elevation. Such experiences (which have never been explained in a credible manner by materialists) are reported by significant fractions of the population. The source here discusses a variety of surveys taken to try to determine how common out-of-body experiences are.  It gives  numbers which suggest that out-of-body experiences occur to significant fractions of the human population, something like between 10% and 20%. Observation of a person's body from some height above the body is extremely common in near-death experiences, which are reported by significant fractions of the population. 

In the long paper here, 14 cases of out-of-body-experiences are discussed. We read this: "In all of the cases that we have described in this paper, the experiencer reported all three features that we discussed earlier as having the most relevance for the question of survival of consciousness: normal or enhanced mentation when the physical body is ostensibly unconscious, seeing the physical body from a different position in space, and perceiving events beyond the normal range of the physical senses."

Rather than assuming that memories that cannot be found in the brain exist in the body below the neck, a better assumption is that memory is a fundamental aspect of the human soul.