The LTP Zap Deceits Continue

 In the English language "lost in the woods" is a phrase meaning "to be confused, bewildered or helpless." Neuroscientists trying to explain how human beings create memories have always been very much lost in the woods. Such scientists have no credible tale to tell on this topic. The problem is that nothing in the brain bears the slightest resemblance to some apparatus or mechanism for storing learned information. Humans create various types of devices for writing information, things such as pens, pencils, paint brushes, typewriters, laser jet printers, offset printers, and the read/write heads used by a computer hard drive. Nothing in the brain bears any resemblance to such things. 

So what do you if you are a neuroscientist trying to fool people into thinking that neuroscientists like yourself have some kind of understanding of how a human could form a memory? What such people normally merely do is to senselessly repeat the same old clueless charade that neuroscientists have been doing for about fifty years: they zap a tiny bit of brain tissue, creating some tiny change that lasts about as long as a suntan or the morning dew, and they try and pass off that little change as something like information storage, even though no information was stored. This is the witless nonsense of LTP experiments. 

What is misleadingly called “long-term potentiation” or LTP is a not-very-long-lasting effect by which certain types of high-frequency stimulation performed by scientists (such as stimulation by electrodes) produces a fleeting increase in the strength of synapses. In 2007 a scientist said on page 120 of her PhD thesis, "While LTP is assumed to be the neural correlate of learning and memory, no conclusive evidence has been produced to substantiate that when an organism learns LTP occurs in that organism’s brain or brain correlate."

So-called long-term potentiation is actually a very short-term phenomenon. Speaking of long-term potentiation (LTP), and using the term “decays to baseline levels” (which means “disappears”), a scientific paper says, "potentiation almost always decays to baseline levels within a week," while noting that even after considering LTP "we would be at a loss for a brain mechanism for the storage of a long-term memory."

The visual below depicts the deceit that is going on in the less deceitful  (but still very deceitful) LTP experiments. In these in vivo experiments, scientists use artificial fiddling to zap the brains of living mice or living rats with electricity, and then wrongly claim or insinuate that this sheds light on what naturally occurs in the brain. The claims are bogus, because when people learn and recall, they do not have electrodes or wires attached to their heads. 

But there is a form of such LTP deceit even worse than the deceit depicted above: the in vitro form of LTP deceit. The phrase "in vitro" refers to observations or experiments involving only tissue outside of a living organism, such as tissue in a test tube or glass beaker.  The typical scientist doing the in vitro form of LTP deceit will zap some dead tissue extracted from the brain of a mouse or rat, and will then insinuate (or have his allies insinuate) that this tells us something about learning occurring in living humans who were not zapped. This kind of deceit is depicted below:

I can give the latest example of the LTP zap deceit. It is a recent press release published by the MedicalXPress site that is a frequent purveyor of misleading neuroscience press releases. We have a headline of "How the brain regulates learning on a cellular level: 3D maps reveal synapses reorganizing in real time." The headline is bogus, because the press release does not discuss a study that did anything to study natural learning in humans or natural learning in animals. All that went on was that tissue extracted from the brains of rats was artificially zapped, and a study was made of synapse changes after such artificial zapping. 

The paper being promoted is the recent paper "Transition of the presynaptic vesicle cluster from a compact to dispersed organization during long-term potentiation."  Contradicting itself, the paper tells us, "Long-term potentiation (LTP) is a lasting form of synaptic plasticity that can persist for hours or even days."  Of course, it makes no sense  to describe something as "lasting" if it only persists for "hours or even days." The long-standing use of the term "long-term potentiation" for this very short-lived effect produced by artificial electrode stimulation is one of the most dishonest speech customs of neuroscientists.  So-called "long-term potentiation" should be called something like "artificially-induced short-term potentiation." The paper incorrectly refers to this LTP as "a cellular mechanism of learning." The description contradicts the paper's previous claim describing LTP as something involving synapses (synapses are not cells). The description also contradicts what the same six authors say in the preprint I mention below, where the authors refer to LTP as a mere "cellular model of learning." A model is not a mechanism. 

It not correct to call the idea of LTP or effects produced by LTP zapping a "model of learning," for the simple reason that in science a model is a detailed theory explaining how something happens, and LTP involves no such detailed theory, but merely the vague idea of "synapse strengthening" or its artificial elicitation, which is something vastly different from having an account of how human experiences and human learned knowledge could be naturally encoded into brain states or synapse states. Scientists have no credible detailed theories explaining how there could occur either memory encoding in brains or memory storage in brains. 

The paper is behind a paywall, but we can assume that the research corresponds to that described in a preprint with a very similar title, the title of "The presynaptic vesicle cluster transitions from a compact to loose organization during long-term potentiation," particularly since that preprint has exactly the same six authors, and mentions exactly the same very narrow topic, and also because I see the preprint repeats (using some nearly identical language) some of the language in the abstract of the published study.  Looking at that preprint, we get the details of what was going on. 

We read of "theta-burst stimulation (TBS) to produce long-term potentiation (LTP)." This is brain tissue zapping. Later we read of "2 hours of theta-burst stimulation (TBS) to produce LTP." So it wasn't just a single brain zap that was delivered, but two hours of brain zapping.  

And the experiment did not involve brain zaps of living rats. The experiment involved the in vitro zapping of brain tissue extracted from rat brains. We read this in the preprint:

"Brain slices from the middle of the rat hippocampus were prepared as previously described. Two concentric bipolar electrodes were lowered into the middle of stratum radiatum in area CA1 separated by 500 µm, stimulating independent axons. Control stimulation (one pulse every two minutes for 40 minutes) was delivered to one of the electrodes and TBS to the other one (8 trains of 10 bursts at 5 Hz of four pulses at 100 Hz delivered 30 sec apart). 2 hours following TBS, the slices were fixed, processed, and imaged."

So the scientists electrically zapped for two hours some dead tissue extracted from the brains of rats, rats who were not even trained to learn anything or remember anything. Can we learn from such an effort anything at all about how learning or memory occurs in living humans who were not electrically zapped?  Of course not. 

But how does the press release discuss this study having no relevance to learning or memory? With a bogus headline of "How the brain regulates learning on a cellular level: 3D maps reveal synapses reorganizing in real time." An honest headline would have been "What happened after they spent 2 hours zapping dead cells taken from rat brains."

LTP research is a cesspool of misleading junk science, and in vitro LTP experiments are the lowest nadir of that cesspool. An honest description of these experiments in news articles and science paper abstracts would have these characteristics:

(1) It would be made clear that artificial electrical stimulation was occurring, unlike anything that occurs in learning humans. 

(2) It would be made clear that the experiments involved rodents, not humans. 

(3) Whenever the experiments involved extracted brain tissue, it would be made clear that the experiments involved only zapping dead tissue stored in something like a test tube.  

(4) It would be made clear that no information storage resulted from this zapping, and that the zapped tissue did not end up storing any data or information  or knowledge transmitted by the electrical zapping. 

Just as sun-tanning from a tanning machine never results in information storage in skin, LTP experiments never produce data or information or knowledge stored in brains or brain tissue.

Part of the deceit involving the terms LTP and "long-term potentiation" involves using such terms to refer both to artificial zapping manipulations and also to natural variations in synapse strengths.  Through this technique writers try to create the impression of LTP as being something that naturally occurs. Erroneously claiming that LTP originally referred to a long-lasting increase, a science paper describes how the term LTP became fuzzy:

"Originally, LTP referred to a long-lasting increase in the synaptic response (potentiation) resulting from stimulation at high frequency (Bliss and Lomo, 1973). Over the years this term became fuzzy as it has been applied to pretty much any increase in synaptic strength regardless of the specific induction procedure."

Real science (as opposed to junk science) involves the precise communication of truth. When writers confuse things so badly that artificial electrical zapping is conflated and confused with natural events going on in brains, then we are in a realm of deceit or confusion much different from well-functioning truthful science. I don't know whether what I describe above as deceit is willful deceit or simply very bad misrepresentation by those who are confused or self-deceived or very careless or very clumsy. But since the first definition Merriam-Webster gives of deceit is "the act of causing someone to accept as true or valid what is false or invalid," I consider it fair to use the word "deceit" in describing these misrepresentations.