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Index of Subjects Hi Dave, Angus & all, Hello Dave -- they were probably not stunned and you almost managed to re-discover the `headless learning` insect preparation first uncovered by my old boss, back in St. Andrews, Scotland in the 60s (though he used cockroaches). This caused a stir at the time because very little was then known about the neural mechanisms behind any kind of learning, of great interest then as now: the search was on for a so-called `simple` system in which to elucidate these mechanisms at the level of single nerve cells, and this insect system looked promising to some at the time. To shock such an insect you need 2 electrodes connected through a switch to opposite terminals of a voltage or current source, as Dave says. If you tether the insect (to stop it running away) so that its front legs rest on one electrode and the body or the other legs touch the other electrode, then close the switch, a roach will immediately raise its front legs, so breaking the circuit and terminating the shock. The elevation lasts for a few seconds then the legs come down. After a few more such shocks, the roach keeps its legs up for longer periods (it has learned by association). This happens even with the head removed, showing that the changes reside in the thoracic nervous system, not the main brain. The ingenious part of this was the `yoked control` -- the same current was sent also through a hapless second roach, which got the same number of zaps as the first, but these were now not related to its forelegs` position and so it failed to learn the `legs-up` trick. This fizzled out after a few years because no-one got very far with the single neuron approach in the thorax and much better preparations were discovered where this approach did work. Eric Kandel, who appears fairly often in science segments on Charlie Rose's midnight TV show on PBS, got the Nobel Prize a few years back for his work on learning in this area, but on different neural systems. So Dave, perhaps you might have got there first. Steve Quoting Angus MacLean <angusmcl@ns.sympatico.ca>: > Hi David: > Wow, David, quite the experiment. Now that I know how fastidious they > are about their appearance, I find myself changing my mind about > them! My wife thinks I would do well, in her eyes perhaps, to follow > their example more. > Thanks, > Angus > > At 10:27 AM 18/11/2009, you wrote: >> Hi Angus, Steve & al, Nov18, 2009 >> The earwig thread prompted me to dig out an old e-mail to another >> site; pasted below. >> >> Abundant or sparse they must feed something else. No longer abundant here. >> DW >> >> START OF PASTE\\\\\\\\\\\\\\\\\ >> Mar 9, 2003 >> On a related note-- >> Shortly after earwigs appeared in Kentville, and started taking over >> lawns & gardens, I wondered about the feasibility of an active earwig >> trap, i.e. using electric shock to herd them into traps, so I borrowed >> some scrap electronic components that when assembled formed a variable >> voltage and harmless low current power supply. To observe behavior when >> they were exposed to shocks, I made a small chute of lucite with thin >> brass strips spaced such that when an earwig walked along the chute it >> closed the circuit. I don't recall the voltages now but, at low voltage >> there was no response, at higher voltage they stepped lively and at even >> higher voltages tiny sparks from foot hairs could be seen in dim light, >> there was sometimes an odor of burning protein and/or earwigs were >> stunned and remained immobile for ~5-30 seconds. Their behavior after >> being shocked and especially after being stunned, convinced me 1) that >> earwigs were just small people with slightly different body parts and 2) >> that one should not herd earwigs by electric shocks even if a trap of >> this kind could be made to work. >> After they came to, they sat back so fore legs were free to move and >> laboriously groomed head, antennae and front leg joints (I can't recall >> with certainly that mid and hind legs were groomed) apparently using >> fluids from the mouth. After this bath, presumably to remove materials >> that are released from between joints when under stress, they would >> resume normal posture and walk off. >> >> >> Yours truly, Dave Webster, Kentville >> END OF PASTE\\\\\\\\\\\\\\\
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