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The location of memory is a bone of contention. Most academics believe some kind of synaptic ping pong takes place every time we think about something. If that's the case, I must be having an amateur tournament.
Toshiyuki Nakagaki of Hokkaido University and his colleagues says it doesn't look quite like ping pong. But, he's at a loss to offer a different metaphor.
His homies start by running a series of experiments testing the memory of a single celled slime mold. They put Physarum on an agar plate and subject it to cold dry conditions for the first 10 minutes of each hour. The cells slow down their activity during the cold spells, return to normal when things warm up.
Three hours later, they stop screwing with the thing and watch for changes in behavior. Curiously enough, at the top of the hour many of the cells behave as though they encounter a cold snap. The "cold response" behavior tapers off over time and immediately returns with the next cold setting - at the correct time intervals. Toshi and his buds repeat the experiment with the same results for intervals ranging from 30 to 90 minutes.
Physarum cells apparently show the ability to memorize and anticipate repeated events. For those of us whose memory is worse for wear: slime molds don't have a brain.
Wed, 5 Aug 2009 15:19:17
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