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nibotI woke up from a dream, feeling well-rested and generally refreshed, with sunshine streaming in through my window onto my face. The sunlight appeared in my dream, as my vision in the dream had become very strange. Horizontal bands of light or something.
I think that being woken up `gently` really helps with the remembering of dreams. I rarely (a small number of times per year) remember my dreams, or even that I had been dreaming. However, a few times this year I remembered my dreams after being woken up by the radio; but these memories were only ephemoral, and faded quickly. The alarm clock is a harsh jolt into reality, involving the piercing noise and a walk across the room. I wonder how difficult it would be to make a home-made EEG (electroencephalograph) to monitor sleep patterns. This could be monitored by a simple device which could produce external stimulus (sound, light) in pursuit of a number of goals: a) wake up optimally so as to remember dreams; b) wake up at the proper point in the sleep cycle so as to feel optimally refreshed; c) investigate lucid dreaming.
When I was much younger, specifically in the third grade, I remembered my dreams vividly, and could usually influence my actions in the dream. This was very exciting not only because the laws of physics did not apply (I could usually fly) but also because my dreams frequently verged on the nightmarish. This phenomenon suddenly disappeared towards the end of grade school and since then I've never really remembered my dreams at all, and I've always wondered why.
Feynmann did some personal `research` on the matter, and his main conclusion was that it is simply necessary to train your memory (by writing down everything you can remember about your dreams when you wake up, for example) in order to (re-)develop the lucid dreaming capacity.
I've talked to my roommate a little about it, and we both have noticed that we tend to remember our dreams a lot more frequently when we're on some kind of vacation from school; somehow the daily stress of school destroys the memory of dreams, but perhaps this is just a result of the sudden-return-to-awakening addressed above. I dunno. It would be fun to make an EEG and investigate the phenomenon quantitatively.
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Re: Electroencephaloscope project
Date: 2002-02-12 04:54 pm (UTC)Wireless would of course be nice, but we'll have to start with wired (minimize complexity). Also, there is the problem that the signal acquisition (discrimination of the microvolt signal against the one volt background) would have to happen before wireless transmission... so you'd have to have an electronics box on your head anyway. So, let's not get ahead of ourselves (no pun intended, hahaha).
I was thinking about data acquisition, and I had the thought that, once we have the signal isolated and amplified (suitable for display on an oscilliscope), we might be able to just pipe it into the microphone input on a sound card. And some kind of audio recorder, perhaps as simple as a regular audio tape recorder, could record signals offline.
I was amused by your note about your computers always being on. I can imagine them monitoring you while you sleep.. and us outsiders could SSH in and see, "Oh, Kaolin is dreaming..."
Re: Electroencephaloscope project
Date: 2002-02-13 02:46 pm (UTC)> says that REM sleep is indistinguisable from eyes-closed-relaxation by
> EEG, which could be problematic for us in investigating dreaming. I
> assume we could add some other sensor somewhere to be able to
> differentiate between the states..
it shouldn't be too difficult to know whether someone is awake or asleep. REM only occurs within a given context of going through other stages, and waking similarly (relatively).
an electrooculogram seems simple enough -- two electrodes, one above and to the outside of the right eye, another below and to the outside of the left eye....
this (http://www.google.com/search?q=cache:0epaCylxi8YC:sensor.phys.dal.ca/minilabs/eye/eye.html+electrooculogram&hl=en) is a good paper that doesn't seem to be available normally. we should probably scalp it and put it somewhere.
"The potential difference between the canthi was measured using an HP 1505A Electrocardiograph. The ECG is essentially a very sensitive difference and isolation amplifier with a typical gain of 1000."
"The ECG outputs were connected to the analog inputs of a PCI-1200 DAQ card, configured in differential mode with unity gain."
Syllabus (http://bisleep.medsch.ucla.edu/sleepsyllabus/fr-a.html) from a course on sleep. really good overview of stuff.
"In practice, the EEG, EOG, and EMG are simultaneously recorded on continuously moving chart paper, so that relationships among the three can be seen immediately. The following are examples of the changes typically seen in these three measures during wakefulness and the major sleep stages (Figures 2 and 3)."
Re: Electroencephaloscope project
Date: 2002-02-13 09:52 pm (UTC)Which is kinda what I was just realizing above.
La la la.
:)
Re: Electroencephaloscope project
Date: 2002-02-14 05:04 pm (UTC)Here's a simple question. I understand the three electrodes used by the EKG: one on either side of the chest, and one far away, i.e. on a foot. The far-away electrode is grounded, just to have a common reference. With respect to ground, the two chest electrodes have voltages V1 and V2. We want to measure the difference (V1 - V2) which is complicated by the fact that the difference is about 1/1000 the value of either V1 or V2. This is accomplished via an "instrumentation amplifier". How do we connect up muliple (more than two) electrodes, however?
Oh yeah, so I read a little bit about "in-amps" and about DAC, and I added some links to the eeg (http://splorg.org/people/tobin/projects/eeg) page. It sounds like there are all kinds of experiments we could do with this.. I'm pretty excited to build one. Just need to find a lab to work in, with soldering irons and o-scopes and whatnot.
Re: Electroencephaloscope project
Date: 2002-02-14 06:04 pm (UTC)> > alpha/beta/theta wave EEG machine, it has all the bits and bobs you
cool cool. does it measure the intensity (read: rms power) of the bandpass
filter of each wavelength or something more complicated? :)
> Now to find some components... I think I am going to try building an
> instrumentation amplifier out of three op-amps before I get a real modern
> in-amp. We'll see. I still haven't found myself lab space at this
> university.
Well, I've got lots of spare toys at home. I wish I had a sillyscope but they
cost a bit. Might be worth it, finally... not that I have any room for it,
but I sorta due. When is your stint in Sweden done? :)
> I'd like to suck the data threw a ADC into a computer. I think it would
> make sense in this case to do some lowpass filtering for antialias
> purposes and then do the rest of the signal processing in the PC. Have
> any comments about PC data acquisition?
Hmm. Why do the signal processing in the PC? That's rather slow. I mean,
it's cool to have raw data, but when you can get physics to do the work, you
might as well let it (though we could record separate channels... raw data...
one sort of filter... another...)
Oooh. I just remembered/looked up/noticed that my EE145L book had an EOG lab,
as well as ECG, EMG...
Huh. you know what else I just noticed/remembered? the EE145L book is also
the EE145M book, just depends on whether you're talking the first half or the
second half. =) =) =) as mentioned previously, 145M is the computer data
acquisition part. Today's valentine's and I'm probably unbelievably busy for
the next four days, but I'll see about scanning through it and see what tools
those experimentsuse. looks like it's just doing A/D and D/A through the
parallel port. Parallel ports are cool (conceptually simpler than serial so
long as your data is in bytes)...
there's a good experiment on doing FFTs of the human voice. should be simple
to do a little filtering and have it work on ECG/EEG/EOG ... :)
just a note, I'd prefer to go with 8bit D/AC. just simplifies the project on hell of a lot, unless we're seriously using someone else's craziness for computer interaction.
hmm, notes on your waveform thingamy: I'd recommend makign a Gdk widget. They're cool. As for redrawing/not redrawing... use double buffering and just redraw the new part that's going onto the screen. you might even want to keep an image twice as wide as what you're displaying and keep that updated, so the refresh is a bare minimum.
as for the three electrodes... the ground is attached to the shielding of the two other electrodes (according to my notes, for an EOG but same setup basically).
Re: Electroencephaloscope project
Date: 2002-02-27 05:22 pm (UTC)Tjernobyl's ultimate goal is to visualize thought with ferrofluid, which I thinks on a number of interests we have, also. :)
maybe we should make a journal just for this project? (I think good idea, so we don't have to keep tracking back to this post).
I haven't had time to look at/play with anything, though I'm looking forward to incorporating the test equipment with wireless stuff. =) oh yeah, I did look at oscilliscopes on ebay a bit. didn't know what I was looking at though. Anyone have recommendations on some high quality low-end oscilloscopes? I'm looking for $300 or under, if possible. (http://www.livejournal.com/talkread.bml?itemid=23608224)
Re: Electroencephaloscope project
Date: 2002-03-22 06:56 pm (UTC)Just found eegspectrum (http://eegspectrum.com) today, looks interesting...
Hamfests and other surplus electronics retailers tend to have cheap scopes... though they've never been cheaper new. Radio Shack has handheld LCD scopes, good for getting a rough idea of what's going on anyway...
Bitscope (http://www.bitscope.com/) is an interesting option as well. 100mhz open design scope with computer interface.
Re: Electroencephaloscope project
Date: 2003-01-14 12:44 am (UTC)Tom Watts