A more remote possibility is that planarian worms themselves have somehow changed over the last six decades\u2014falling victim to pollution or genetic drift. Gershman finds this scenario unlikely. \u201cWhat are the chances that a bunch of researchers just happened to do these studies at the particular time when this phenomenon happened?\u201d he asked, incredulous. \u201cThey just got extremely lucky, in the millions of years of planarian evolution? And then our luck ran out?\u201d<\/p>\n
No matter the reason, in 2026, despite their nervous system and simple brains, planarians don\u2019t learn. From an evolutionary perspective, this might actually make sense. \u201cThe reason that we learn associations, to some degree, is so that we can predict danger and avoid it,\u201d Snyder said. But planarians have a different relationship to danger. Their regenerative physiology, so key to McConnell\u2019s experiments, protects them from blunt trauma. Bitten in half, they simply grow back. What use is memory to such a creature? \u201cThat\u2019s a whole other philosophical conundrum,\u201d she said.<\/p>\n
It\u2019s a great time to be wrestling with such conundrums. Planarian learning may be a dead end, but memory transfer experiments with other organisms are back in scientific vogue\u2014and those experiments appear to be working. In 2018, the neuroscientist David Glanzman of the University of California, Los Angeles, performed a memory transplant<\/a> on the sea slug Aplysia californica, a darling model organism<\/a> for memory research owing to its relatively simple nervous system and gigantic neurons. After training the slugs to respond to a shock to their tails, Glanzman was able to transfer the sensitization from one slug to another via a direct injection of genetic material<\/a>. This suggested that some aspect of the memory was stored in RNA, which was McConnell\u2019s contention.<\/p>\n Then, in 2021, the Princeton University geneticist Coleen Murphy found that Caenorhabditis elegans worms\u2014microscopic roundworms with 302 neurons to their name\u2014could learn to avoid a pathogenic bacterium by eating, or even just swimming around in<\/a>, pureed worms who had learned the hard way. Murphy\u2019s group identified a retrotransposon, a jumping segment of genetic material, called Cer1, that appears to \u201ccarry a memory<\/a>\u201d between individuals, she said. A few years later, a group at the Indian Institute of Science published a paper suggesting that trained C. elegans worms release extracellular vesicles\u2014small lipid particles containing genetic information\u2014that can impart their training<\/a> to their na\u00efve counterparts.<\/p>\n None of these researchers are half as flashy as McConnell was, but their work indicates that he may have been right about worm memory after all. He just bet on the wrong kind of worm\u2014and doubled down on it, despite inconsistent evidence. In the end, he lost his reputation, but his sheer gusto sparked the curiosity of another unconventional scientist. Fortunately, this one\u2019s following the evidence.<\/p>\n At Harvard, Gershman is shifting his focus from the inscrutable planarian to the more legible C. elegans. It may not regenerate when it\u2019s cut in half, but C. elegans is a long-standing model organism in neuroscience<\/a>\u2014and it\u2019s been consistently shown to learn. With new experiments underway, Gershman is cautiously optimistic. \u201cI just hope we\u2019re not going down another rabbit hole,\u201d he told me. A wormhole, on the other hand\u2014that\u2019s for certain.<\/p>\n Original story<\/a> reprinted with permission from Quanta Magazine<\/a>, an editorially independent publication of the Simons Foundation<\/a> whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.<\/p>\n","protected":false},"excerpt":{"rendered":"A more remote possibility is that planarian worms themselves have somehow changed over the last six decades\u2014falling victim…\n","protected":false},"author":2,"featured_media":670800,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[13533,61,60,184000,3021,87,413,18290,82,217037,58271,176641],"class_list":["post-670799","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-animal-behavior","tag-ie","tag-ireland","tag-memories","tag-memory","tag-neuroscience","tag-psychology","tag-quanta-magazine","tag-science","tag-scientific-method","tag-scientific-research","tag-worms"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/670799","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=670799"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/670799\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/670800"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=670799"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=670799"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=670799"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}