The EurekAlert site at www.eurekalert.org is yet another "science news" site that seems to just pass on press releases coming from university press offices. Nowadays university press offices are not a very reliable source of information, as they tend to display all kinds of "local bias" in which the work of researchers at the university gets some adulatory treatment it does not deserve. University press offices often make grandiose claims about research done by professors at their university, fawning or hype-filled claims that are often unwarranted. The press releases from university press offices often make unimportant or dubious research sound as if it was some type of important breakthrough.
The EurekAlert site says that it is "a service of the American Association for the Advancement of Science." That makes it sound like we would be getting some kind of "official science news" or at least news of better-than-average reliability. But very strangely at the bottom of each news story on the site, we read this notice: "Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system." That basically means that we should not trust any headlines we read merely because they appear on the EurekAlert site. At the post here I discuss various untrue headlines that appeared on the EurekAlert site.
The latest untrue headline to appear at the EurekAlert site is a headline from two days ago, one which stated "USC team shows how memories are stored in the brain, with potential impact on conditions like PTSD." Nothing of the sort occurred. All that happened was that some scientists tracked some new synapses being created and an equal number of synapses being lost after some tiny zebrafish learned something.
We read text in the story that contradicts the story's headline:
"They made the groundbreaking discovery that learning causes synapses, the connections between neurons, to proliferate in some areas and disappear in others rather than merely changing their strength, as commonly thought. These changes in synapses may help explain how memories are formed and why certain kinds of memories are stronger than others."
Notice the contradiction. The headline claimed that the team had showed how memories are stored in the brain. But the text of the story merely makes the much weaker claim that the type of thing observed "may help explain how memories are formed."
The quotation above is not even an accurate description of what was observed. The scientists did not find that synapses "proliferate in some areas and disappear in others." Instead what was observed in each area of the zebrafish brain studied was a roughly equal number of gains of synapses and losses of synapses. Below is one of the visuals from the paper (from the page here and the site here). It shows synapses losses and gains in only one tiny part of the zebrafishes brain during a small time period. Notice the blue dots (representing synapse losses) are roughly as common as the yellow dots (representing synapse gains).
Data results such as this are best interpreted under the hypothesis that we are merely seeing random losses and gains of synapses that continually occur, and that the result has nothing to do with anything being learned. It has long been known that synapses are short-lived things. 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." Synapses randomly appear and disappear, just as pimples randomly appear and disappear on the face of a teenager with a bad case of acne.
Zebrafish have only about 100,000 neurons, and there are perhaps 1000 synapses for every neuron. That makes very roughly about 100 million synapses in the zebrafish brain. Given synapses that have average lifetimes of no greater than a few months, we would expect that every hour about 100,000 synapses in the zebrafish brain would randomly be lost or would randomly appear. The synapse loss and gain shown in the USC data is about what we would expect under such numbers. The visual shows hundreds of synapse losses and gains, but this visual only maps such losses and gains in a tiny portion of the zebrafish brain.
The type of learning tested on the zebrafish was something called tail-flick conditioning or TFC. At the link here we are told this:
"The total numbers of synapses before TFC are not significantly different among the different groups: superlative learner (L, N=11 fish), partial learner (PL, N = 6), nonlearner (NL, N=11), US only (N=11), NS (N=11), and CS only (N=11) (p > 0.3, Kruskal Wallis).
B The total numbers of synapses after TFC are not significantly different among the different groups (p > 0.3, Kruskal Wallis)."
So there was no increase in synapses for the zebrafish who learned something (the L and PL groups) compared to the zebrafish who did not learn anything (the NL group). The study has not produced any evidence that learning or memory formation produces an increase in synapses.
The study also failed to support the widely-made claim that synapses strengthen during memory formation or learning. In the EurekAlert
story we read this:
" 'For the last 40 years the common wisdom was that you learn by changing the strength of the synapses,' said Kesselman, who also serves as director of the Informatics Division at the USC Information Sciences Institute and is a professor with the Daniel J. Epstein Department of Industrial and Systems Engineering, 'but that’s not what we found in this case.' ”
Oops, it sounds like neuroscientists have been telling us baloney for the past 40 years by trying to claim that memories are formed by synapse strengthening (an idea that never made any sense, because information is never stored by a mere strengthening of something). The USC scientists have not presented anything that can serve as a credible substitute narrative. "Synapses being lost at the same rate as synapses being gained" makes no sense as a narrative of how memories could be stored, just as "words being written at the same rate as words being erased" makes no sense as a description of how someone could write a book using pencil and paper.
By visually diagramming the high turnover rate of synapses, and by reminding us of the short lifetimes and rapid turnover of synapses, what the USC study really has done is to highlight a major reason for rejecting all claims that human memories are stored in synapses. Synapses only last for days, weeks or months, not years; and the proteins that make up synapses have average lifetimes of only a few weeks or less. But human memories often last for 50 years or more. It makes no sense to believe that human memories that can last for 50 years are stored in synapses which last a few months at best, and which internally are subject to constant remodeling and restructuring because of the short lifetimes of synapse proteins.
In an article he wrote at the site The Conversation, USC scientist Dan Arnold describes his own results in a give-you-the-wrong-idea way, stating the following: "When we compared the 3D synapse maps before and after memory formation, we found that neurons in one brain region, the anterolateral dorsal pallium, developed new synapses while neurons predominantly in a second region, the anteromedial dorsal pallium, lost synapses." The results (as shown here) were actually that both regions lost and gained synapses at roughly equal rates. Arnold confesses, "It’s still unknown whether synapse generation and loss actually drive memory formation."
So why is it that the press release for this work contained the untrue headline "USC team shows how memories are stored in the brain, with potential impact on conditions like PTSD"? Why is it that scientists so very often allow very untrue press releases about their work to be issued by the press offices of their universities, press releases that are making claims that are not supported by their work, and claims that often contradict the statements of such scientists? Is it because scientists are willing to condone lying hype to appear about their work, for the sake of getting more of the paper citations that scientists so much long for (the paper citation count being for a scientist being a number as important as a baseball player's batting average)?
A particularly pathetic aspect of the phony press release headline is that this counting of synapse losses and synapses gains in tiny zebrafish has a "potential impact on conditions like PTSD." Such research has no relevance to humans with post-traumatic stress syndome, and the claim that it does is as phony as the claim that the study "shows how memories are stored."
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