Wednesday, August 29, 2012

dream science?

Too many entries - let this be the last one for August.

Fantastically, incredibly, unbelievably, implausibly, Monday night I had a dream that directly relates to Monday's entry. I'll leave out irrelevant details: I dreamed that I was experiencing a migraine aura.

In the dream, I noticed the phosphene-like foveal scotoma, and at first had the "is it an afterimage? what bright light did I look at?" reaction, and then realized what it really was. It was upsetting, actually, because the last one was just 1 week previous, and I felt like once a week is a bit too frequent.

I then set about trying to record the aura with my perimetry program, except that my computer was now a large, flat panel lying on the floor, like a giant i-pad. The layout was of course different - not a blank gray screen, but a thin-line black grid, like a Go board, on a wood-brown background. Jingping was there, and kept trying to move the grid around, and I kept telling her to stop.

Once I was trying to record it, the scotoma was no longer foveal, but extended 10-20 degrees out, straight to the left and then arcing downward towards the inferior vertical meridian. This makes me think that I wasn't actually experiencing an aura in my sleep - to get from the foveal scotoma to 10-20 degrees should take 15-20 minutes, and I don't think that much time actually passed in the dream - it seemed like less than a minute. Of course, time and space are both funny in dreams, so who knows. There was no headache on Tuesday, anyways.

It was very frustrating trying to set the fixation point in the dream perimetry program. I just couldn't fixate - I would set it in one place, and then felt that it should be somewhere else. I think I finally gave up and started sticking my hand in the scotoma to probe its size.

So, whether or not I was really experiencing an aura, or just dreaming that I was experiencing one, is an interesting question. It seemed like a real one, and I noted lots of spatial details: the tiny phosphenic bead of the foveal scotoma, the fuzzy noisiness of the peripheral scotoma arc (though the periphery seemed clearer somehow in than true peripheral vision), the thin black lines of the perimetry grid, the unfixable fixation spot.. If visual experience includes V1 activity, and if the visual aura occurs in V1, and if V1 is quiet or suppressed during dreaming, how could I have seen what I did, unless spatial vision includes a good deal of higher-level inference?

It seems that I proposed an experiment on Monday afternoon, and then did the experiment in my sleep that night. I have never been so efficient!

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