Planaria Memory

[Orb]

You know, I was taught that planaria would gain the knowledge of their cannibalized brethren when I was in JR. High! Granted that was 13-14 years ago, but a heck of a lot later than the 1930's! I had no idea that wasn't true. :mad: Does anyone else remember learning this?

Edited for clarity.

[Jeff Corey]

Look up James V. McConnell or The Worm Runner's Digest.

[aggle-rithm]

You know, I was taught that planaria would gain the knowledge of their cannibalized brethren when I was in JR. High! Granted that was 13-14 years ago, but a heck of a lot later than the 1930's! I had no idea that wasn't true. :mad: Does anyone else remember learning this?

Edited for clarity.


I remember it. From what I recall, the experiments involved first chopping up the planaria and letting it regenerate into numerous new individuals, each which remembered a task taught the original. From this the hypothesis of RNA memory was constructed, and the "cannibalism" experiment followed.

I remember that the source of this information (I can't remember if I was taught it at school or read it in one of my many childhood science books) made it clear that planarians are not humans. Their invertebrate nervous system is much simpler. A human couldn't assimilate memories from a random body part any more than he/she could regenerate from dismembered pieces.

[Jeff Corey]

Good thing, too. Otherwise they might consider recycling professors emeriti.

[jpenn]

Recycling intelligence… Hmmmm. Does anyone remember “Soylent Green”

[aggle-rithm]

Recycling intelligence… Hmmmm. Does anyone remember “Soylent Green”


Mmmmm.... Soylent Green.....

[Piggy]

Soylent green is planaria! Soylent green is planaria!

[tracer]

I remember that the source of this information (I can't remember if I was taught it at school or read it in one of my many childhood science books) made it clear that planarians are not humans. Their invertebrate nervous system is much simpler. A human couldn't assimilate memories from a random body part any more than he/she could regenerate from dismembered pieces.
Too bad for those information sources that the memories weren't being "assimilated" by the flatworms at all; they were just following trails that earlier worms had left.

[Jeff Corey]

Not true. There were no trails to follow. It was Pavlovian conditioning, not maze learning.

[Piggy]

Not true. There were no trails to follow. It was Pavlovian conditioning, not maze learning.
Actually, I believe McConnell's experiments were indeed maze learning.

[Piggy]

On second look, seems to have been both (http://www.woodrow.org/teachers/bi/1998/planaria/backgroundpage.htm), first classical conditioning, then task performance.

More here (http://www.everything2.com/index.pl?node_id=826389) and here (http://en.wikipedia.org/wiki/Memory_RNA).

[Jeff Corey]

In any case, there were no trails to follow. Maybe in old rat studies, but not in any of McConnell's.
"Well,you can't really dust for vomit."
Nigel Tufnel

[Piggy]

In any case, there were no trails to follow. Maybe in old rat studies, but not in any of McConnell's.

Interesting. I don't know much about these tests.

So where do the cites I provided have it wrong? Wiki doesn't cite McConnell by name as running maze studies, but the everything2 post does. The Woodrow site refers to task experiments by McConnell.

So what actually happened?

[Jeff Corey]

The first studies involved Pavlovian (classical) conditioning, pairing a light with shock to condition body contraction to the light alone (CS).
http://www.dur.ac.uk/robert.kentridge/bpp2mem1.html
The maze studies came later, but involved the planaria swimming through them, making it unlikely that they were leaving trails. In dry rat mazes, odor trails must be removed after every trial run.