Month: September 2022

VINDICATION. "Everything changed when, in late 1965, four independent labs reported successful memory-transfer experiments using rats (and in one case, cross-species transfer between rats and mice). Two of these reports appeared in the high-impact journals Science and Nature." https://lnkd.in/esKEPF7 View in LinkedIn

RAT NEWS. "No one could argue that rats cannot learn. Within a few months, more than 50 labs, including teams at Berkeley, Harvard, MIT and Yale, conducted transfer experiments. McConnell, after failed attempts using salamanders and mynah birds, also turned to rats. And then things got really interesting." https://lnkd.in/esKEPF7 View in LinkedIn

METHODOLOGICAL CONSTRAINTS. "These remarkable discoveries have not had sufficient impact on the field and were largely abandoned because of practical difficulties inherent in manual experiments. While the basic findings were validated in some cases, they failed to be reproduced in others, and the whole line of research became abandoned." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

SAMPLING SIZES. "Manual behavior experiments involve limited sample sizes, difficulties in precise reproduction of protocols, and lack of quantitative analysis. As a result of these difficulties, even the capacity for long-term memory planarians has been questioned." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

THEORY CATCHES UP. "While modern discoveries such as epigenetic modification and RNAi now offer mechanistic explanations of some of the original results, the primary barrier to molecular-level investigations into the dynamics of memory during CNS regeneration has remained: the difficulty of developing a robust learning assay in planarians." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

BIAS. "McConnell's results are now attributed to observer bias. No blinded experiment has ever reproduced his results of 'maze-running'. Subsequent explanations of maze-running enhancements associated with cannibalism of trained planarian worms were that the untrained flatworms were only following tracks left on the dirty glassware rather than absorbing the memory of their fodder." https://en.m.wikipedia.org/wiki/Planarian View in LinkedIn

MIXED RESULTS. "These remarkable discoveries have not had sufficient impact on the field and were largely abandoned because of practical difficulties inherent in manual experiments. While the basic findings were validated in some cases, they failed to be reproduced in others, and the whole line of research became abandoned." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

RECENT VINDICATION. "In 2013, Tal Shomrat and Michael Levin have shown that planarians exhibit evidence of long-term memory retrieval after regenerating a new head." https://en.m.wikipedia.org/wiki/Planarian View in LinkedIn

NEW METHODOLOGY. "To establish a system for the investigation of the dynamics of memory in a regenerating brain, we developed a computerized training and testing paradigm that avoided the many issues that confounded previous, manual attempts to train planarians." (Shomrat and Levin, 2013). http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

MINIMAL BIAS. "Our protocol minimizes bias caused by manual procedures, allows an unprecedented level of quantitative rigor in behavioral analysis, and applies the procedure to a large sample size in a relatively short time frame. Additionally, in contrast to Best and Rubinstein's protocol, our procedure checks for long-term memory, several days after the training ended." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn