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Living Fossils Have Long- And Short-term Memory Despite Lacking Brain Structures Of Modern Cephalopods

Date:
June 1, 2008
Source:
The Journal of Experimental Biology
Summary:
Nautilus, the ancient living ancestors of modern cephalopods, have both long and short-term memory, despite lacking the brain structures that modern cephalopods evolved for long-term memory.
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Nautilus, the ancient living ancestors of modern cephalopods, have both long and short-term memory, despite lacking the brain structures that modern cephalopods evolved for long-term memory.
Credit: iStockphoto/Dmitry Rukhlenko

Robyn Crook from the City University of New York reports that Nautilus, the ancient living ancestors of modern cephalopods, have both long and short-term memory, despite lacking the brain structures that modern cephalopods evolved for long-term memory.

Nautiloids are the sole surviving family of externally-shelled cephalopods that thrived in the tropical oceans 450--150 million years ago. However, in the intervening years their modern soft bodied relatives dumped the shell and developed complex central nervous systems; which makes Nautilus ideally suited to discover the 'evolutionary pathways that led to the development of the complex coleoid [soft bodied cephalopod] brains' say Robyn Crook and Jennifer Basil. Knowing that the simple Nautilus brain lacks the structures required for memory in more sophisticated cephalopods, Crook and Basil decided to test the living fossil's memory.

Training Nautilus pompilus to associate the smell of food with a blue light, the cephalopods eventually learned to respond to a flash of blue light by extending their tentacles. Then the scientists tested the cephalopods memories with a flash of light 3min, 30min, 1h, 6h, 12h and 24h after training. Amazingly, Nautilus remembered their training for up to an hour before the memory was lost, but then the memory returned 6h later, lasting up to 24h. Nautilus has both short and long term memory, just like modern cephalopods, despite lacking the same brain structures.

Crook and Basil are optimistic that the unsophisticated Nautilus brain could teach us how modern cephalopod brains evolved.


Story Source:

The above post is reprinted from materials provided by The Journal of Experimental Biology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Crook, R. and Basil, J. A biphasic memory curve in the chambered nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea). Journal of Experimental Biology, 2008; 211 (12): 1992-1998 DOI: 10.1242/jeb.018531

Cite This Page:

The Journal of Experimental Biology. "Living Fossils Have Long- And Short-term Memory Despite Lacking Brain Structures Of Modern Cephalopods." ScienceDaily. ScienceDaily, 1 June 2008. <www.sciencedaily.com/releases/2008/05/080531074905.htm>.
The Journal of Experimental Biology. (2008, June 1). Living Fossils Have Long- And Short-term Memory Despite Lacking Brain Structures Of Modern Cephalopods. ScienceDaily. Retrieved September 4, 2015 from www.sciencedaily.com/releases/2008/05/080531074905.htm
The Journal of Experimental Biology. "Living Fossils Have Long- And Short-term Memory Despite Lacking Brain Structures Of Modern Cephalopods." ScienceDaily. www.sciencedaily.com/releases/2008/05/080531074905.htm (accessed September 4, 2015).

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