Claims by neuroscientists that they have found "representations" in the brain (other than genetic representations) are examples of what very abundantly exists in biology: groundless achievement legends. There is no robust evidence for any such representations.
Excluding the genetic information stored in DNA and its genes, there are simply no physical signs of learned information stored in a brain in any kind of organized format that resembles some kind of system of representation. If learned information were stored in a brain, it would tend to have an easily detected hallmark: the hallmark of token repetition. There would be some system of tokens, each of which would represent something, perhaps a sound or a color pixel or a letter. There would be very many repetitions of different types of symbolic tokens. Some examples of tokens are given below. Other examples of tokens include nucleotide base pairs (which in particular combinations of 3 base pairs represent particular amino acids), and also coins and bills (some particular combination of coins and bills can represent some particular amount of wealth).
Other than the nucleotide base pair triple combinations that represent mere low-level chemical information such as amino acids, something found in neurons and many other types of cells outside of the brain, there is no sign at all of any repetition of symbolic tokens in the brain. Except for genetic information which is merely low-level chemical information, we can find none of the hallmarks of symbolic information (the repetition of symbolic tokens) inside the brain. No one has ever found anything that looks like traces or remnants of learned information by studying brain tissue. If you cut off some piece of brain tissue when someone dies, and place it under the most powerful electron microscope, you will never find any evidence that such tissue stored information learned during a lifetime, and you will never be able to figure out what a person learned from studying such tissue. This is one reason why scientists and law enforcement officials never bother to preserve the brains of dead people in hopes of learning something about what such people experienced during their lives, or what they thought or believed, or what deeds they committed.
But despite their complete failure to find any robust evidence of non-genetic representations in the brain, neuroscientists often make groundless boasts of having discovered representations in brains. What is going on is two types of things:
(1) Misspeaking and language abuse by neuroscientists, in which they misleadingly use the term "representations" to refer to mere fleeting blips of brain activity that may properly be called "neural correlates" but not honestly called "representations."
(2) Pareidolia, people reporting seeing something that is not there, after wishfully analyzing large amounts of ambiguous and hazy data. It's like someone eagerly analyzing his toast every day for years, looking for something that looks like the face of Jesus, and eventually reporting he saw something that looked to him like the face of Jesus. It's also like someone walking in many different forests, eagerly looking for faces on trees, and occasionally reporting a success.
Let's consider the first of these two things. You are using language in a misleading way when you refer to a mere correlate as a representation. I will give an example. Imagine you do a study in which you photograph faces of American football fans when their team scores a touchdown. You might be able to detect a correlation between the times that a touchdown was scored and particular expressions of fans. You may find that football fans are more likely to look like this just after a touchdown was scored.
But you would be speaking in a misleading way if you called such an expression a "representation" of a touchdown. The expression is merely one that is a correlate of a touchdown: it is an expression more often occurring when a touchdown occurs (and also when any successful play occurs, such as a long run or a long pass).
There is in American football an actual representation of a scoring event: the sign that a referee makes when he places his two arms up in the air. So the sign below is an actual representation of a football touchdown or a field goal.
It is a big mistake to be using the term "representation" when referring to something that is merely a correlate. This is mistake that today's neuroscientists keep making.
Let us consider some EEG readings or brain scans that may be taken of some organism when the organisms see something and then respond to that thing. Visual perception causes greater activity in the visual cortex of that brain. Such an increase is merely a correlate of the seeing of something, not a representation of what was seen. When presented with some stimulus such as a piece of cheese put in front of it, a mouse may move its muscles to move toward the food. Muscle movements produce spikes in EEG readings. But if you pick up a spike in an EEG reading when a mouse moves toward some cheese, that is not correctly called a representation of the cheese. It is instead merely a neural correlate of responding to the cheese.
The paper "Brain-wide representations of prior information in mouse decision-making" is an example of a recent science paper misspeaking when using the term "representation." No representations were actually found. All that was observed were neural correlates. The authors confess, "It remains unclear where and how prior knowledge is represented in the brain." The truth is that no evidence has ever been found of learned knowledge stored anywhere in the brain of any organism.
The paper "A brain-wide map of neural activity during complex behaviour" is is another example of a recent science paper misspeaking when using the term "representation." The paper studied mice with implanted electrodes. The authors have section titles such as "Representation of visual stimulus," "Representation of choice," "Representation of feedback," and "Representation of wheel movement." All of these uses of "representation" are illegitimate.
Let's look at each of these sections:
"Representation of visual stimulus": It soon becomes clear that all that the authors have picked up is fleeting correlates of something a mouse has seen. We read, "a decoding analysis based on the first 100 ms after stimulus onset revealed correlates of the visual stimulus side in many cortical and subcortical regions." The 100 ms refers to a mere tenth of a second.
"Representation of choice": All that the authors have picked up is fleeting neural correlates of muscle movements associated with the choice. We have another observation window of 100 milliseconds, merely a tenth of a second. The analysis going on is correctly described as "neural correlates of muscle movement associated with a choice," but not correctly described as "representation of choice."
"Representation of feedback": All that the authors have picked up is fleeting neural correlates of mice getting some reward, within an observation window of a fifth of a second. This is no actual "representation of feedback."
"Representation of wheel movement": All that the authors have picked up is fleeting neural correlates of muscle movements. Such neural correlates are not correctly described as representations.
How in theory might you get actual evidence of a brain making a choice? It could not be through any research involving mice. It could only be done with humans. It might work rather like this:
Humans would have their brains scanned, or be connected to EEG devices allowing their brain waves to be read. The human subjects would be offered a choice between two different foods. The subjects would be instructed to close their eyes and remain motionless, as a countdown timer ticked down: 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0. The subjects would be instructed that when the timer reached 0, they should silently make a choice in their minds as to which of the foods they would select, and then remain motionless for another 30 seconds. The interval of the countdown could be varied, with it sometimes being 20 seconds, sometimes 20 seconds, and sometimes 10 seconds.
The data would then be analyzed by blinded analysts, who did not know what moment corresponded to the timer reaching 0, and did not know which choice was made. The analyst would attempt to figure out which of the two choices was made, purely from the brain data. The analyst would also attempt to figure out at which second the choice was made, purely from the brain data.
The experiment would fail. Excluding the neural correlates of muscle movements, brains do not show any sign of being involved in decisions. When a person makes a decision without moving his muscles or changing his facial expression, there is no neural correlate of this action. Brains have no actual representations of decisions, and no actual representations of beliefs, or anything someone has learned.
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