Friday, November 20, 2020

No One Can Credibly Explain Why a Brain Would Store a Memory in One Specific Spot

 The theory of the Christmas activity of Santa Claus is one that very small children will accept, but a theory that a child will discard once he gets a little older.  There are too many obvious detects in the theory for a mature mind to hold it: the impossibility of fitting toys for all the world's children in a single sled, the impossibility of such a sled being able to deliver millions of toys on a single night, and the impossibility of Santa Claus getting into so many locked homes.  Like the theory of Santa Claus, the theory that brains store memories does not hold up well to scrutiny.  Among dozens of good reasons for rejecting the theory, there are:

  • the fact that brain proteins have a lifetime of less than two weeks, which is 1000 times shorter than the longest length of time that humans can remember things (60 years or so);
  • the fact that no one has any coherent explanation as to how human learned knowledge could ever be translated into neural states or synapse states;
  • the fact that humans can form new memories instantly, much faster than the time required for some kind of cellular or synapse modification to occur;
  • the fact that no one has ever found any trace of stored information (other than the DNA information in all cells) by studying brain tissue;
  • the fact that removing half of someone's brain (as is sometimes done to treat epilepsy patients) has little effect on memory;
  • the fact that no one can explain how a brain (without any indexing system and without any position notation system) could ever instantly find the exact spot where some memory was stored in it, which would be like instantly finding a needle in a haystack. 
The more we scrutinize the theory that memories are stored in brains, the more problems we become aware of. Let me discuss a problem that was not one of the 30 reasons I previously gave for rejecting the claim that memories are stored in brain, but a different reason.  I refer to the problem that no one can give a credible explanation as to why a brain would store a memory in one specific spot in the brain. 

Let us consider some examples of information storage, and consider the question:  when a piece of information is stored, why is it stored at the specific place that it is stored?

Example of information storage

Why is the information stored in the specific spot where it is stored?

Arrival of a new email

All new emails are put at the top of a “stack” of emails

A student taking notes on one day in a class on some subject

The student selects a subject notebook, and writes at the first blank page of the notebook

A person making a diary entry

The person makes the entry in whatever page is marked with a date corresponding to that day's date

You save a new file on your computer

You are provided an interface allowing you to select some folder or directory on your digital device. After you choose a name for the file, the operating system in your computer creates a new file in the specified location, using an operating system routine for selecting empty space in that location.

You buy a book, and take it to your house

You manually select at random an empty space on a bookshelf, and put the book there

You receive an important letter you want to save

You select the appropriate file folder in your file box or file cabinet, and stick the letter in that file folder

You add an item to a “to do list” document you have on your computer

You simply scroll down to the end of your document, and write the new item at the end of the document

You just type some new text in whatever computer document you are currently working on.

Within your document is a blinking cursor that represents the current position, and your newly typed text is added at that position in your document.

You take a new photo with your digital camera. 

The digital storage card in your camera is like a stack of photos, and each new photo gets added to the end or beginning of the stack.

So we can see that when information is physically stored, there are specific reasons why particular items of information get stored in specific locations. Let us now consider the human brain, and the theory that a new memory gets stored in some tiny little spot in the brain. Such a theory raises the question: why would a brain store some new memory exactly at that spot, rather than any of 10,000 other little spots in the brain? There are various possibilities you can imagine, but none of them seem to be credible. 

One possibility you might imagine is that a brain puts a new memory kind of "at the top of the stack" or "at one end of a chain." Being very imaginative, you can imagine extraterrestrial organisms that might have some kind of stack-like brain or chain-like brain, so that the organism might put each new memory at the top of such a stack or at one end of such a chain. But the human brain bears no resemblance to a chain or a stack. There is no "end writing position" or "first writing position" in the brain to which a brain could write if it were following a "put new information at the end" rule, or "put new information at the beginning" rule. 

Another possibilty you might imagine is that a brain might have something like a cursor or a movable write unit that moves from place to place in the brain to write memories at different locations. If the brain had such a thing, we could explain why a brain would store a memory in one specific spot. The explanation would simply be that the writing of a new memory occurs at whatever location the cursor or movable write unit is located. However, the human brain has no such thing as a cursor or movable write unit.  There is nothing that moves around in the brain other than electricity and chemicals.  We can certainly imagine some strange extraterrrestrial organism with a brain including a movable writing unit having the job of moving around in the brain and writing to different locations, but there is no sign of any such thing in the brain. 

You do not get around this difficulty of explaining why storage would occur at some exact location by speculating that there is one tiny brain region (such as the hippocampus)  where the brain stores all its new memories.  For such a region of the brain would consist of 10,000 smaller sub-regions, and the question would always remain: why was the memory put in one specific spot rather than in any of the other 10,000 spots?

We cannot get around this difficulty by imagining that a brain simply selects a random brain location to write some memory.  The selection of one specific random location is something that a human mind or a computer program can do, but there is no evidence that the human body ever subconsciously selects a random location in the body.  If you ask me to select a random city in America, I have knowledge of the cities in America and a mind capable of performing such a random selection task.  But it would be absurd to maintain that a brain has some kind of subconscious knowledge of some set of possible brain locations where a memory could be written, and some kind of subconscious ability to make a random choice from such a set of locations, choosing subconsciously a random place to write a memory. Nor could we ever explain how a brain (completely lacking in any coordinate system or position location system) could ever cause a memory to be stored exactly in some precise spot that it had randomly selected. Such a thing would be as hard as writing to hay strand #282,035 after your mind had randomly chosen such a hay strand as the place in a huge hay stack where something should be written.  

You also do not get around this difficulty by speculating that a brain stores a single new memory in very many separate spots, as that creates a host of difficulties such as how the memory could be divided up into so many different spots, and how the information could be instantly distributed to so many different spots. Then there would be the extremely great difficulty that a memory stored in many different spots would be like scattering each word on a page so that each word was stored in a different spot in your home. Just as such a thing would make it a thousand times harder to instantly retrieve the information on the page, a memory scattered among a thousand different brain places would be vastly harder to retrieve, making it all the more harder to explain how humans are able to instantly retrieve a memory.  Moreover, if we imagine a thousand different storage locations for a single memory, then we simply have the original problem a thousand times worse; for the question would be: why were those thousand locations chosen rather than any of a million other possibilities for the thousand places to store the memory?

There is no credible theory of how a neurally stored memory would end up in one specific spot in the brain, rather than any of a thousand other little spots in the brain.  What I have discussed here is only one of very many reasons why the idea of a neural storage of memories is untenable. 

Let us consider a case in which a memory arises, and what neuroscientists would need to explain under the theory that memories are stored in brains. Let's imagine a case in which a 13-year-old boy is scared very bad when someone sticks a gun in his mouth. The boy grows into a man who remembers this event for 70 years; and whenever he sees a hand gun (even guns with a different color or caliber), he instantly thinks of that moment when someone placed a gun in his mouth. Here are the things that would need to be explained under the theory that memories are stored in brains.
  • How a brain could instantly form a permanent memory (for such a memory would appear instantaneously as soon as this traumatic event occurred), at a speed many times faster than the minutes required for some protein synthesis needed for synapse strengthening or synapse modification. 
  • How a brain could translate into neural states or synapse states this sensory experience of having a gun placed in your mouth.
  • How a brain could somehow select some location (among countless thousands of brain spots) for this memory to be stored.
  • How a brain could somehow find such a location inside a brain that has no coordinate system and no position notation system, so that the memory could be stored in such a location.
  • How a brain could instantly retrieve this memory whenever the boy saw a gun, which would be like instantly finding a needle in a haystack, given a brain with no coordinate system and no position notation system.
  • Why such a memory could be retrieved by a brain, even when the person saw guns of a different color and caliber than the gun that was inserted in his mouth. 
  • How this neural memory trace would somehow be translated into a recollection briefly active in the person's mind after he saw a gun years later. 
  • How this memory could ever be accurately stored and accurately recalled (with a transmission across innumerable synapses) in a brain with so much signal noise that each time a signal passes across a synapse, it is transmitted with a reliability of less than 50%. 
  • How this memory could be preserved for 70 years, in a brain consisting of proteins with such short lifetimes (two weeks or less) that 3% of the brain's proteins are replaced every day. 
To  explain this case of the boy instantly forming this memory in a brain and remembering it for 70 years, neuroscientists would need to explain all of these things. Neuroscientists cannot even give a credible explanation for any one of these things.  

1 comment:

  1. Memories would presumably have to be stored via information. All information can, in principle, be represented by a string of numbers, say 100011011000. But how would we know what memory that such a string of numbers represents? Books can contain lots of info, but we only understand them as we know the meaning of English words. We also have to remember the meaning of English words. Likewise we have to remember what memory 100011011000 stands for. As it stands it's not a memory any more than a knot in a hanky is.

    So we need further info. Something like 111001? But then we get the exact same objection. How do we know what 111001 stands for? Yet more info? Then we get an infinite regress.

    My view is that memories cannot and are not stored. We have to be in touch with them directly, so to speak. Compare to vision. We may not be able to see something clearly, even misinterpret what we are seeing. But that doesn't rule out we are not directly seeing that something i.e we are not just acquainted with a representation of the seen object in our minds.