03 January 2004


I think I’ve managed something I should have done some time ago. I think I’ve finally managed to record some action potentials....


This is an extracellular recording of sensory neurons in nerve 2 of an abdominal ganglion of a crayfish (Procambarus clarkii) tail. At one point in this recording, the tail flexed spontaneously, so about one third of the way in from the left, you see a substantial increase in the number of spikes (neural activity). It’s a recording of many neurons at once, so you see lots of spikes with different sizes and shapes and such.

Turns out that the major problem was that I’d wired some cables together wrong. Stupid DIN plugs. Fortunately, my crack about British engineers didn't stop me from getting good help from the hardware support people and Cambridge Electronics Devices, who made my amplifier and analogue/digital board. And it was good to know that my grief over soldering plugs and cables together yesterday actually paid off.

The next step – well, it’s not so much a step as a marathon. I’m going to have a ton of refinements to do to make sure that I'm getting good recordings. I have to make a bucket more cables and connectors and wires. And I really have to convince myself that this isn’t all some weird recording artefact that has nothing to do with the crayfish. Heaven knows I’ve been fooled before, but let’s not talk about that.

Oh, and here’s something to make the British engineers feel batter: another old joke. “In heaven, the police are British, the food is French, and the engineering is German. In hell, the police are German, the food is British, and the engineering are French.”

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