Memories that can survive decapitation.

By Seriously Science | July 15, 2013 10:00 am

Photo: flickr/Rodrigo Diaz Lupanow

If one animal could become an honorary superhero, my vote would be for the planarian. This flatworm has truly astonishing powers of regeneration. Accidentally cut off your planarian’s head? No problem! It will grow a new one … and its old head will grow a new body, giving you two pets instead of one! But that’s not all. According to this study, if you trained your original flatworm, both of the animals that result from cutting it in half will remember the training. That’s right — planarian memories can survive decapitation. Anyone out there know of an animal with a real-life superpower more awesome than that?

An automated training paradigm reveals long-term memory in planaria and its persistence through head regeneration.

“Planarian flatworms are a popular system for research into the molecular mechanisms that enable these complex organisms to regenerate their entire body, including the brain. Classical data suggest that they may also be capable of long-term memory. Thus, the planarian system may offer the unique opportunity to study brain regeneration and memory in the same animal. 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 planaria. We then used this new system to train flatworms in an environmental familiarization protocol. We show that worms exhibit environmental familiarization, and that this memory persists for at least 14 days – long enough for the brain to regenerate. We further show that trained, decapitated planaria exhibit evidence of memory retrieval in a savings paradigm after regenerating a new head. Our work establishes a foundation for objective, high-throughput assays in this molecularly-tractable model system that will shed light on the fundamental interface between body patterning and stored memories. We propose planaria as a key emerging model species for mechanistic investigations of the encoding of specific memories in biological tissues. Moreover, this system is likely to have important implications for the biomedicine of stem cell-derived treatments of degenerative brain disorders in human adults.”

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CATEGORIZED UNDER: fun with animals
  • JonFrum

    I learned about the planarian at a summer day camp at the old Children’s Museum in Boston back in the 1960s – cool stuff.

  • facefault

    McConnell’s 1960 memory transfer experiment got false results because the new planaria were following trails left by the old planaria, didn’t it? I read this paper, and didn’t see any way their procedure would control for that.

  • j2saret

    I did some experimental design for a psychology degree involving the transfer of memory in planeria. It turns out that the untrained worms ingested chunks of trained tissue from the trained worms. The worm was too simple an organism for results to have any use.
    The old Worm runners digest might be on line so my facts can be checked.
    Planaria are just the cold fusion of the life sciences

  • Greenisgood

    I am growing a TickleMe Plant that moves like an animal when you Tickle It! Just google pet TickleMe Plant…you may not believe this is real!

  • Flightlessbird1983

    Planerians have proglottids that are complete packages needed for regeneration and these proglottids can form endless chains for regenerating endlessly.

  • 1064nm

    Enquiring minds want to know: How do you “train” a flatworm? Btw, planarians have been a favorite animal since my first microscope at age 9.


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