Month: September 2022

OLD FINDINGS. "McConnell's original results revealed a pattern of ‘savings’, where the learning curve of retrained animals is better (faster) relative to that of to naïve animals." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

DOLDRUM PERIOD. "Although extensive work on planarians' learning and memory has long suggested that memories can survive brain regeneration (McConnell, 1966), the limitations of previous manual experiments have led to these important questions being largely neglected by recent workers; these limitations included small sample sizes, difficulties in precise reproduction of protocols, and lack of quantitative analysis." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

CONFIRMATION OF RESULTS. "Our results support the findings of Best and Rubinstein, and show a statistically significant shorter feeding delay for the familiarized worms compared with unfamiliarized worms. Most importantly, the memory survives long enough to allow for regeneration after amputation, and indeed we show that memory traces survive entire brain regeneration in a ‘savings’ paradigm." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

MEMORY TRACES. "Worms that had regenerated from headless fragments from original familiarized worms displayed significant shorter feeding latency compared with unfamiliarized worms, suggesting that memory of the original environment was not located exclusively in the brain, and had become imprinted onto the newly built brain during regeneration. In the past, such results have been received with skepticism." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

REVIVAL OF OLD FINDINGS. "Our data reveal the presence of memory savings in regenerated tail fragments from trained worms. We suggest that some trace of memory is stored in locations distributed beyond the brain (because the place conditioning association survives decapitation)." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

AFFIRMATION. "Our results, obtained using a highly sensitive, objective, quantitative analysis system, support previous findings of Best and Rubenstein that planarians are capable of acquiring a relatively complex, explicit-like memories of environmental familiarity." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

NEW PHASE OF RESEARCH OPENS. "Moreover, this memory survives long enough to allow full regeneration after amputation. Remarkably, headless fragments, regenerated from original environment-familiarized worms, display significant environmental familiarity in a savings paradigm." http://jeb.biologists.org/content/216/20/3799 View in LinkedIn

SO ENDS this fragment of historical interest that continues to survive controversy, and with new methods has vindicated an old finding that used problematic procedures. That a memory trace can survive regeneration in planaria is an intriguing finding. More, that a molecule can contain such detailed information as a specific behavior. A memory encoded in a molecule that can be reawakened in a new host. Remarkable. View in LinkedIn

SONG OF DARWIN. "The more I study nature, the more I become impressed […] that the contrivances and beautiful adaptations [acquired through natural selection] transcend in an incomparable degree [those] which the most fertile imagination of the most imaginative man could suggest with unlimited time at his disposal." (CD). http://www.sciencedirect.com/science/article/pii/S0960982214003881 View in LinkedIn

POLYMERIZATION CYCLES. "Tkachenko and Maslov have proposed a new model that shows how the earliest self-replicating molecules could have worked. Their model switches between "day" phases, where individual polymers float freely, and "night" phases, where they join together to form longer chains via template-assisted ligation. The phases are driven by cyclic changes in environmental conditions, such as temperature, pH, or salinity, which throw the system out of equilibrium and induce the polymers to either come together or drift apart." https://publishing.aip.org/publishing/journal-highlights/origins-life-new-model-may-explain-emergence-self-replication-early View in LinkedIn