Saturday, June 29, 2013

toronto

just in time to make it 2 for June:



Notes at the Robards Library on the U.Toronto campus, 3:30 pm on 6-26-13.

My feet are very tired. Got up this morning at 5, took a shower, kissed my wife goodbye, and went out to meet the waiting taxi. Had a coffee at the airport.

Got on the prop plane to Toronto at 6:30. Had a coffee on the plane, with a muffin and a cup of yogurt. Clearly I am thinking of food.

Looking out the plane window while we were still on the Boston tarmac, I noticed that I could see the flicker of sunlight through the propellers - I was sitting right next to the front of the left engine, on a plane that was two thirds empty - but only in my periphery. So the propellers were rotating no faster than 60 Hz. Once we went to take off and the engines revved up, I couldn't see the flicker anymore - revving up meaning revving faster, you see.

Got to Toronto by 9, the Billy Bishop airport, on a little island on the lake in front of the city. First person off the plane, last through customs. Canadian customs are actually pretty challenging! Dunno what was up with that.

Then, took a 1 minute ferry ride to the shore, and walked north on Bathurst street. Made it to Kensington market and found a little open air restaurant to get breakfast. It was almost 10. I was already soaked with sweat. Ninety degrees out, humid, and not a cloud in the sky, and I'm wandering the streets of a strange city with a 10 pound bag on my back and a poster tube on my arm. I had a cheese omelet, which came with salad and hashbrowns, it was pretty good. And toast.

I am so hungry. I then wandered for about an hour, through Toronto Chinatown, until I came to the Toronto Art Gallery or whatever it's called. Bought a ticket and discarded my luggage, and wandered the museum for 3 hours. Best part by far was the set of installations on the fourth floor, something I've never seen before: little repeating 3-d audiovisual pieces, rooms full of stuff with recordings playing - some of the recordings were little dramas, one was just a rainstorm, from start to finish. It was great. Had a coffee at the museum.

Then I left the museum and went the wrong way, south instead of north, deeper into the city instead of towards the University of Toronto. Finally I made it here, and now I'm resting in the library, cooling off and writing these notes. I took lots of little videos of my day so far.

From here, I need to 1) get something to eat, 2) get to a subway station, 3) figure out how to use the Toronto subway, and 4) use it to get to York, or as close as I can (then I have to take a bus, apparently). If all goes well I'll be at York University in no less than 90 minutes. Wish me luck! I'm so hungry.

part 2, 18:56pm, June 28 2013

Meeting is over. Sitting in the weird weird weird Billy Bishop Airport departure area/lounge. It would be much nicer if half the flights weren't delayed because of some storm.

Meeting was interesting. Had several talks with F.K., about my current in-review JOV paper, for which he is one of the reviewers; about my current little blur adapt project that I presented (to 3 people, I think) here at this meeting, he had some very helpful comments there; and on other random spatial vision lightness brightness topics. Lots of fun, I think talking to him made the whole meeting worthwhile.

Also met with D.G., as a sort of pre-interview for a postdoc position. Not sure I want to really apply. I was testing to see if it was something that might be up my alley, definitely far up it, but now I'm thinking maybe too far. It's probably too much of a stretch to try to work natural scenes and spatial vision into the level he's working at. I'll study his work over the next couple of weeks, then let him know.

Also managed lunch with F.W. to discuss migraine psychophysics. She seems to have cooled a bit on the migraine spatial vision business, but is still interested. Similar attitude to N.H. about the difficulty and unlikelihood of having migraineurs do vision tasks or perimetry during their auras, though I am not convinced. I will take the long view. M.D. is enthusiastic, I met with him last week. I am almost thinking of writing an entire proposal out, it seems it would be relatively straightforward. I feel I've put all the requisite pieces together, i.e. bounced ideas off all the important people. The main thing that's missing is predictions as to how certain psychophysical properties might be influenced, which is something that L.L. brought up on his own. So now, it seems I should get back to him.

Interesting things I saw... C.B.'s keynote address was pretty bad. I don't know what the general opinion was, but it seemed for the wrong audience - like he was addressing a bunch of visual physiologists in 1992. Don't know what was going on there. Good talks were R.K. on superior colliculus, showing us maps and explaining function, things that if I've ever learned them I've forgotten; G.L.'s talk was interesting, reading and training reading with CFL patients; H.W.'s talk was good, R.B.'s I thought was too much review; A.P.'s talk on form perception and V4 was very interesting. A.P.'s and R.K.'s were like little topical seminars on things I didn't know; I guess R.B.'s was similar but I already knew all of it. D.Z. gave a talk on how MRI magnets affect the fluid in the semicircular canals, resulting in constant nystagmus for anyone who gets into an MRI machine. I remember the slight shock I got the one time I was put in an MRI magnet, but I don't remember noticing nystagmus. I might have thought it was concentration problems, instead.

So that was the meeting. Mostly good, a little slow in some places. I got to attend the retirement of the great H.W.. Poster sessions were too brief, barely worth the trouble, though I did get F.K.'s comments and H.W. came by and didn't complain about anything, though he didn't volunteer compliments or suggestions either. He thought the phase filter was a neat idea, though.

***

Observations on Canada

The way of speech is different. They do say 'soarry' instead of 'sarry', and they say it a lot. I hear a lot of 'os' instead of 'as', 'possengers' instead of 'passengers'. There's something else, a character that feels narrow somehow. I don't know what 'narrow' means there, but it feels right, so I'm using a word that feels right to describe a feeling that I can't otherwise describe. May all be in my head.

The York campus, which is in the northern Toronto suburbs, had lots of animals. I saw a raccoon, a groundhog, and a rabbit, and lots of black squirrels. I saw the groundhog and the rabbit at the same time. I don't think I've seen a raccoon up close since I was a kid, probably out at the cabin or something. And I'm not sure I've ever seen a groundhog up close. This was all right in the middle of campus.

When I was trying to get up to York, just having gone into the Spadina station, I got turned around and lost and couldn't find my way. An older guy, long white hair bound up behind his head, heavy set, white beard, noticed that I looked confused, stopped, and told me where to go.

Again, I feel that the people are different. A part of it must be in the speech, which sounds American but is subtly different. I think a professional would be necessary to explain the differences completely. Multiple idioms that I've heard from C* and D*, many times up here. I wish I could explain the feeling better, because I don't think it's all language. Maybe more visits will resolve this place better for me. It may be because this is big Toronto City, but people seem to dress strangely, less conservatively than Americans in general. Gaudiness isn't standard but seems more common than on Boston streets, at least. I guess I can't generalize from Toronto to Canada. Toronto is clearly an immigrant city, I would say barely half the people I saw in the city were white, lots of Chinese, black, brown, etc. In that sense, it reminds me more of San Francisco or LA. It's very unlike Montreal, which did not have such an American appearance, and which at the same time was much more white.

Aside from the people, it looks exactly American. No obvious differences in infrastructure. The York campus has lots of tunnels and connected buildings, which I would guess is more due to the winter cold and snow and not some sort of Canadian preference for warrens. When I walked through the city I got feelings of China-ness somehow, I think because there was so much construction going on. Nothing about watching the streets makes it look different in any obvious way from watching American streets.

All flights are delayed by hours. Some are nearly canceled. I don't know what's going on, must have been a string of storms across the northeast.

First time ever, I saw another Tennesseean at a vision meeting. He was an undergraduate from MTSU of all places, said he was from Bellevue. I questioned him a bit and he just talked and talked. Despite being from Bellevue, he seemed not to have heard of Cheatham County or Kingston Springs, and so I didn't like him. Complained of Tennessee as a place to escape, where no one wants to return. How can you want to escape if you don't even know your surroundings? Not that I'm not ambivalent about this myself, and I'm half over as old as this guy, but I don't think I was ever that bad. Main thing that rubbed me wrong was that he talked too much, which I guess is just a personality trait. It will probably get him places, I don't know.

Back to Canada. The buses were just like American buses. The subways were regular subways, long cars like the China style, where you could walk from end to end. Spadina station where I first got on was a link between two lines, one of which I didn't travel on, but it looked a lot like the Boston green line, trolly cars running through tunnels. I would have liked to try that one. The friendly white-haired guy got off one of those.

Forgot to mention til now, had a headache yesterday morning, give it a 7, maybe even 8. Woke up with it and it got worse through the morning, coming and going. Quasi-hangover, but I'd just had 3 beers with a full dinner the night before, not enough for a real hangover, though I think the alcohol probably did cause it, in addition to dehydration from the long trek across the city and the general relief of arrival. Slept terribly Wednesday night, partly from the headache starting, and partly from Terry calling and texting me every 10 minutes starting around 6am, probably had barely 5 hours total.

Right eye trigeminal was sore, still sore today, but the headache disappeared over lunch yesterday, went from a 7 to nearly zero. I was still a bit dazed and confused, but got over it pretty quickly. Slept well last night, got at least 8 hours in, maybe more.

Wednesday, June 12, 2013

accidental maxwellian view?

Busy this month, and keeping it to myself so far.

The title of this post is just a guess. Let's talk about some interesting entoptic (or maybe just optic) phenomena.

First is something that I've noticed before, in the same context that I'm going to describe here, but also during our winter trip to China in late 2011, lying in bed one morning and watch the sunrise through the curtains, with my eyes full of sleep.

I'm standing at Fenway Station, waiting for the train to come and take me home. I'm soaking wet because its pouring rain and I didn't take an umbrella. My glasses are specked with water droplets. The sun has set.

I find that I can attend to the fine structure of the images projected on my retina (I'm doing this one eye at a time) through the water droplets. This is a little strange, since the droplets are just a couple of centimeters in front of my eyes, so it should be impossible for me to focus on them and to resolve such fine details, but I'm doing it anyways.

The droplet images - for the most part circular, disk-shaped - look like something between an amoeba and an image of the sun. The amoeba-ness is from their speckled, squirmy, internal structure, like a bag of little bits and pieces. The details are fine, near my acuity limit. The sun-ness is from their perimeter, which has a rim that stretches outward, like the corona of the sun in eclipse. I will draw a picture and put it here, since I can't find anything like it on the internet.

These things I've noticed before. My theory is that the droplets are acting as little lenses, focusing an image near my pupil, which is then - in a sort of accidental Maxwellian view - getting perfectly focused on my retina. The structure I'm seeing is the texture of the interface between the water and the surface of my glasses, little bits of dust and et cetera. It's like seeing a water droplet through a microscope, which adds (through psychological association perhaps) to the impression of seeing an organism. The rim is the edge of the droplet, the meniscus, and the corona is the stretching of the edge due to surface tension.

All that is just a guess! Nobody I talk to seems to have a good explanation, but that seems as good as any.

The next part I had not seen before.

I found that in my left eye, but not in my right, when I blinked, I saw bright specks, pin points of light, against the background of the droplets. I couldn't see the specks outside of the droplets.

When I attended more closely, I discovered extremely fine structure to the points of light. Basically, they looked like this:

I tried a sinc function, but that wasn't quite right, because I couldn't see more than a couple of rings, like you see here. What you see here is the product of a radial sin function, with the center set to 1, and a radial Gaussian. In words, each pin point was surrounded by a black ring, which was surrounded by another bright ring, then a dim ring, and then I'm not sure. Each little point was the same as the others, but I had to get them near the fovea to see them clearly. They were tiny; they each were only a few arcmin across. And, they were bright: the central point was white, and the ring surrounding it was black.

I really don't know what these things were. I have forgotten a crucial detail: did they move when my eye moved? I feel that I could look from one to the other, but I don't remember if this is really how it was, or if it's just how it seemed. If that's how it was, they can't have been on the surface of the eye, and it's hard to explain why I only saw them in the left. At the time, it made sense to me that they were on my cornea, specks of dust, so I think they must have been fixed to my point of view. They slowly faded and became less distinct, and I would occasionally blink to restore them.

So, weirdness at Fenway.

Friday, May 24, 2013

Binding Problem

I am still evolving, as I read all this NCC stuff, but in testing myself and my thinking, I find that I produce something very similar to what I have produced several times in the past year or so (also under the Vision tag):


My view has been that the phenomenal visual scene can be likened to a stack of qualia or phenomenal properties, all simultaneously experienced or bound together in such a way that it is often difficult to see the bound parts as distinct from one another, although they are distinguishable in principle. The root of this stack is the set of phenomenal properties that I believe are most often identified with ‘qualia’, i.e. properties that have scalar magnitudes or intensities. Brightness and darkness, color, contrast, and then at a slightly higher order, orientation, scale, direction, speed. These are familiar as physical objects of study either in the psychophysical field of spatial vision, or as determinants of sensitivity in the neurophysiology of the first few synapses of the initial retinocortical pathway for visual encoding. But they are not the only phenomenal properties of visual scenes, and in fact they are not the properties of scenes that we spend the most of our ordinary visual time analyzing. Instead, we spend most of our visual effort attending to more fuzzily inferred properties of the scene: identities, utilities, depths, valences, affordances. These are the properties of a scene that are immediately apparent to us, but they are the ones that require the most inference: the shape and meaning of a word; not so much its contrast or color, which we can easily adapt to and forget, although they remain in our phenomenal consciousness. I am reminded what Foucault said regarding the multiple layers of a calligram: “As a sign, the letter permits us to fix words; as line, it lets us give shape to things.” All these things are simultaneously present and part of the seen scene, but we tend to attend selectively to certain levels.

I think it is clear from this conception of the phenomenal scene that indicating the presence of phenomenal properties, i.e. that something is present in consciousness, requires the presence of the higher level inferences, but not necessarily of the lower level ‘root’. I can daydream or close my eyes and continue to experience visual phenomena, although they are indistinct and insubstantial, and I can tell you about what I experienced, and then we can argue over whether or not visual imagery constitute visual phenomena. However, if all I have is the spatial scene, but I am unable to make any inferences about it, then I cannot report anything about it – reporting presumes context, or cause, or object, and these all require higher level inferences. Or rather, perhaps I could report, but my reports would be nearly meaningless, not least because objective meaning is tied to subjective meaning, which is what we have removed in this example. My reports would, at best, maybe with some minimal inferences, allow me to transmit information about the perceptual magnitude of local, ‘low-level’ features. I would then be performing in a psychophysics experiment, and you would probably be using signal detection theory to interpret my responses. Norma Graham noted the strange convenience of this situation more than 20 years ago, when she noted, “It is (or we can hope it is) as if the simplicity of the experimental situation has made all the higher level stages practically transparent.”

Sunday, May 19, 2013

[last Monday, the 13th,  I woke up with a great headache that lasted more than 48 hours. left side on the first day, right side on the second. nothing else particularly interesting.]

notes after midnight on May 17, 2013

When I was about 12, I could go outside some afternoons, in my backyard, and see giant helicopters flying across the sky, with what looked like trucks and tanks suspended below on long cables, in long processions, one giant helicopter after another. That would have been nineteen-ninety, ninety-one, the Gulf War. Just now, on my last night in this house, to which my family moved in winter of nineteen eighty-five, when I wasn't yet six years old, I went out to the car to get the computer that I'm now writing on, and I hear a roar, a helicopter, coming from the southeast. I stand and wait to see it, and can't find it, as it's getting so loud that I can feel the vibrations. I'm confused at the conflict between what I hear and what I don't see, just a sky of stars, and then I see it, an enormous shadow, a blank space against the stars, flanked by dim lights, and the sound I hear finds its match.

Now I lay on the floor of the living room, what we called the room where my mother's pianos sat for more than 25 years, which is now empty but for little piles of human junk here and there. I'm sleeping here just for the strangeness of it, and because I figure if I sleep in my old bedroom, a smaller space as the boy who painted cats might advise me, I will get a cave cricket in the mouth. Usually a room looks larger when you clear it out, but the piano room looks smaller without the pianos. The true nature of the house is revealed in this room, a set of almost ramshackle wooden boxes, this room the boxiest of all of them.

I get to hear the crickets and frogs outside, and the constant truck of I-40. I mentioned the stars. And I get to spend one last night in this string of boxes in the countryside, set in an undrainable swamp, in the Harpeth hills. Only yesterday did I get that cliched phrase - you have these hills or those hills, hills is an appendage for a pleasant or obscure prependage. But this place is in the hills, and it was flooded by the Harpeth only 3 years ago, so I think it deserves the name.

I'm not sure what to make of all of it. I never quite understood my surroundings when I lived here, I only saw what was just at my nose and never questioned it or looked further, though I thought I did. Now I think I know how to see further, but coming back here and wandering around, I feel the old ignorance surface, and it's a strange feeling of simultaneously knowing where I am and never having known, and really only knowing that I'll probably never be back.

Sunday, May 12, 2013

may may may



May's a slow month even when I don't go to VSS, I guess. One post last year in May, and may be this is the only one for 2014.

Bunches of stuff going on. Flying into Huntsville Wednesday. Procrastinating on a short fellowship application to go to Melbourne. Pestering a professor in Nashville for a job. Doing lots of cleanup work in Boston, finishing big papers, reviewing other people's papers, fixing RA projects, starting little papers. Practicing Chopin waltzes and Bach sinfonias to pass the time. Read Plato's Apology and Crito last week, still haven't committed to Phaedo. Started playing RoTK XI again this weekend. Cleared out of the kitchen on orders from my landlord. Playing with natural scene statistics, inventing new analyses. Always, always trying to learn Chinese.

Despite all this, I feel as though I'm doing nothing at all. Perhaps this is an explanation? I don't know, I haven't read it.

Saturday, April 27, 2013

midnight aura

Olive the Cat wakes me up every morning sometime between 2 and 5, and I go put food in her bowl. This morning, at 2:30, I'm awakened by her scratching at the baseboard, and as I wake up I think I see fortification spectrum... turns out I'm about halfway through an aura. Left visual field, about 15 minutes in (noting for reference that the pain is on the right side, supraorbital nerve). I debated turning on the computer so I could record the remainder, but I think it was too far along to be worthwhile. The spectrum extended from fovea straight left, then arced downward. I watched it for a while - I'm still impressed at how straight it is at that point, I wonder if the CSD wave somehow gets caught up in the base of the calcarine sulcus.

The scotoma seemed very small, even when the wave was well into the periphery the blind region didn't seem thicker than the scintillations. The scintillations were very clear, whereas usually I don't see them very clearly - maybe because I was dark adapted the whole time, or my brain was in a sleepytime state, or maybe it was just a random thing. I did notice that closing my eyes, even though it didn't change the apparent luminance of the scene very much, made the phosphenes completely disappear for several seconds, and they would fade back into view only weakly, slowly. I couldn't go back to sleep for ~45 minutes. Ears were almost ringing, headache started. Minor, 5/10.

Yesterday, and maybe Thursday, several times, I noticed flashes, spots, in my periphery, and thought, 'something is up'. Yesterday afternoon, I'm sitting at my computer, reading text near the lower bezel, and I feel I see a phosphene or blind spot just below fixation, where the aura usually starts - it lasts ~10 seconds and disappears. Maybe that represented a false start? The cortex is weakly susceptible, and maybe there are false starts, and then it kicks off - or doesn't. Also, after the syncope episode, I've started to wonder if the tinnitus I get now and then is, at least sometimes, an aura - I had an episode yesterday.

I was dreaming about something as I woke up, and it seemed relevant somehow, but of course I've completely forgotten it now.

Wednesday, April 24, 2013

feeling very aggravated today, not going to say why. i want a new job. i said too much already.

intermittent intense photophobia the last couple of days, and much of today a strange buzzing distant feeling - could be that aggravation, but i'm voting prodrome. see what happens in the next few days.

ugh. is this even worth posting? i wrote a poem on patriot's day about the marathon bombing, but i'm not going to show it to you. it was four stanzas, four lines each, with a loose rhyme scheme as follows: xxxA, xxxB, ccxA xxxB. that's all you're getting.

i feel like my mind is a dismantled car engine, pieces scattered across the floor. is that how it seems to other people? my mind, i mean, is that how it seems to them, when they perceive it? what am i saying, when do others have an opportunity to perceive my mind? ugh. a dismantled engine scattered across the floor in a locked room, and the lights are too bright.

Friday, April 12, 2013

syncope

quick note:

went for the mri tonight; radiologist said everything looks ok, but wait to see what the neurologist says; and i can come get a copy of the pictures next week. mri was interesting, hypnotic, staring at a blank plastic surface inches from your face, keeping absolutely still, listening and feeling these musical, super loud rhythms coming from the machine.

interesting in a different way was what happened first: the nurse tried to put a contrast agent into my blood through a vein in my arm; she failed on the first time, sticking the needle into the vein and through the other side; the second time, she hit a nerve, and i went into vasovagal syncope.

everything started to tingle, my field of view started to fade, i broke into a sweat, i felt nauseated, and then

then, everything was black, and i didn't know anything or sense anything - yet i had some sort of minimal awareness. i had a vague feeling of waking up from a deep sleep in a place i didn't know. i remember feelings that i associate in some way with sunlight, trees, and mountains. i felt confused.

then, i started to feel my body - i was in a chair, but i couldn't move. why am i in a chair? where am i?

then i started to hear a shuffling sound, loud and abrasive, felt my body being rifled back and forth - the confusion was growing.

then my vision came back - when i asked her later, the nurse said my eyes were open all along, deviated down and leftward - and only then i remembered i was in the MRI clinic. at first i thought, when did i go to sleep? i wasn't sleepy.., and then i realized that i must have passed out. everything started to come back.

the nurse was calling for the doctor and others to come, and struggling to put a blood pressure meter on my arm. the sounds were all muffled for about 30 seconds or so, as though i had earplugs in. at the same time, there was intense tinnitus.

after a few minutes i felt normal again. the shuffling noise, i think, was blood rushing back into my ears, and maybe also the agitated movements of the nurse. i was soaked with sweat. they gave me a can of juice and an oxygen tube in my nose. i didn't notice anything interesting about the oxygen. i talked with the amused radiology resident, Amad, and we decided not to do the 'GAT', the contrast, unless the scan turned up something worrying, which it didn't.

this was the first time i've ever passed out, but i often get woozy from needles, getting blood drawn etc, and i stopped giving blood in college because each time the wooziness got worse - the last time i couldn't walk out of the clinic, had to lie down for 20 minutes. point is, this wasn't important, just weird.

so, the quick note is: order of losing consciousness - all at once. order of regaining consciousness - awareness of self, body, hearing, and vision. glad i've been reading those tononi papers - i would estimate my phi went something like this:

Thursday, April 11, 2013

physics and psychophysics

reading papers on "information integration theory" lately. up to this most recent one - barrett and seth, PLoS-CB 2011 - i had an okay grasp on the math, but now i'm considering skimming. the first author of this paper is a theoretical physicist by training, so i don't feel too bad that i can't quite take it. feeling a little bad led me to this train of thought:

in my field of psychophysics we use mathematics to describe human behaviors, with those behaviors driven by simple physical stimuli. some psychophysical models can be rather complicated, but the more complicated they get, the less realistic they get, because so to speak they inevitably start biting off more than they can chew. for example, channel theory is a bunch of mathematical objects, but they have to be fit to particular contexts. even a simple psychophysical rule or law involves constants that vary from person to person, from apparatus to apparatus.

no one in psychophysics should fool themselves into thinking that they can someday come down to a simultaneously correct and meaningful mathematical theory of whatever phenomenon they are studying, because every phenomenon is an artificially isolated part of a much more complicated whole, and the ways that the circumstances of the phenomenon can be varied are nearly infinite. but thankfully, no one in psychophysics does, i think, fool themselves this far; we recognize that mathematics is a good tool for getting a handle on what we are studying, at the same time that what we are studying is clearly variable in ways that we can only hope not to approximate too poorly. for us, mathematics is an operational description of what we're studying.

in physics, on the other hand, they have things down to the level where you will hear physicists talk about mathematical objects and physical phenomena as more-or-less the same thing. quarks and bosons, gravity and magnetic fields, are things that are only really understood through mathematics. my knowledge of physics mostly comes from reading feynman and hawking, and watching random lectures (and once having been a physics undergrad, briefly), so it's not like i have anything like an up-close viewpoint of the physicist's perspective, but i think this viewpoint is plainly very popular. john wheeler talked about the root of all reality being information, which is only a mathematical construction as far as the human mind is concerned - obviously he felt the isomorphism was close enough to make this sort of claim.

apparently, for physicists to achieve this nearly perfect mathematical description of physical reality, the mathematics had to get pretty complicated. so, when you read a paper by a physicist on a topic that you feel like you should have a good handle on - you're a psychologist, the topic is consciousness - you have quite a bit of difficulty in parsing his descriptions, even though you realize that he's not talking about anything approaching the sophistication of string theory or QED.

so.. i'll go back and give it another 20 minutes, maybe make it another half-page. also, tomorrow night i'm having an MRI of my neck, to check for dissections in my carotid arteries. fun fun fun.

(only now did i realize that this topic would have been perfect for a new dialogue.. maybe i will recast it?)

Tuesday, April 09, 2013

visual cortex is weird

Migraine weirdness:
1. The weekend after the AF, neck was constantly sore in a weird way. No sign of headache. Soreness disappeared yesterday (Monday).
2. Monday saw waves of photophobia, but it never lasted more than twenty minutes or so, or it was low-level enough that I could adapt to it, and wouldn't notice until the ambient light changed.
3. Today, a bit of photophobia and a faint headache, slightly nauseated. Am I just hyper-sensitive? Also, this morning when I awoke, saw the m-scaled lattice that I've mentioned before; it flashes on for just a few hundred milliseconds, and fades as the morning-light bedroom scene comes into view. I would say it looks most like Form Constant III as described by Bressloff et al (no I am not on any drugs, though Bressloff prefers to refer to drug-induced hallucinations):

(This image is from Bressloff et al's 2002 Neural Computation paper. Note the coincidental opposite symmetry between this kind of m-scaled 'spiral' pattern and the ancestor map in the previous post, which can be seen as another kind of spiral lattice - something like what you'd get if you plotted a flat lattice in the visual field and looked it it in cortical space.)

Also, to reiterate an observation I made in the AF post, in light of reading all this stuff about integrated information and consciousness over the past few days: migraine scotoma are invisible, unlike the disturbingly visible grayness I saw when my left retina stopped working. The normal explanation for the invisibility of cortical scotoma is that it is "filled in", which I've always felt was fishy.. I know it's well-studied, and now I'll have to read about it.

My feeling is that there is no filling in, at least not in the way it's usually talked about, but rather that the scotoma is a scotoma in visual space period - if you don't see the space, you don't see any blankness, and you see the scene continue directly from one side to the other, not knowing any better. Maybe it's hard to justify this intuition, but I think it's similar to noting (as hemianopia patients do) that beyond the edges of the visual field, there's not an expanse of nothingness, but rather no expanse at all. If there is no expanse, there is no edge, so you get the strange condition of not being able to see the boundaries of your own visual field, because the boundary would have to be defined as between two expanses. With a proper mapping between visual direction and field location, you can be properly aware of the geometry of the visible field, without any need for it to be bounded. (Put another way, topologically, the space behind my head is equivalent to a hole in the visual field - if I can't perceive that space as being bounded by the same boundary as the visible field, why should I be able to see the boundaries, and the invisible expanse, of a cortical scotoma?)

Friday, April 05, 2013

ancestral geography

 
I've not been working on this too much, but I took a couple of hours yesterday to fill in another space in my records, and then I got the idea to make the figure you see here. The tree plot is a map of all my known ancestors, with their distances from the center scaled to their birth years, relative to my birth year of 1979. Red lines are women, blue lines are men. The rings are labeled as to year.

The colored backgrounds indicate - by correspondence with the geographical map on the right - where these people were born, or at least where they spent their early lives. Where they combined to produce the next generation tells you, more or less, where they wound up.

The dominant region is clearly West Tennessee, whence hailed my mother's mother's people and my father's father's people, going back to before the Civil War (the double ring). My mother and many of her father's people came from Southeast Tennessee, part of the crimson. My father's mother's father came from Michigan, just across the border from the source of most of his family in northern Indiana, indicated by the magenta.

There's a lot of northern South Carolina, in the region of Spartanburg and, just across the border in southern North Carolina in Mecklenburg county, indicated by the yellow. A branch of my mother's mother's family had come through Kentucky, the light green.

Middle Tennessee, the olive green, has generated a number of us, including a part of my mother's father's family (the ill-fated Lewis Morgan and his mother Nancy Sewell, who must have been in the first generation born in Nashville), and my father and myself at the center.

If you follow this further out (I stopped 6 generations back, at the four-greats grandparents level), everyone that I know of is in Virginia (you can see those touches of orange in the periphery), South Carolina, Pennsylvania, Massachusetts, or Ireland. It is amazing what you can learn from the internet!

Thursday, April 04, 2013

amaurosis fugax

Yesterday, about 5 o'clock, sitting at my desk. Go to stretch, arms behind me, pulling on my shoulder, started to greyout (I don't know a better term for this - whatever you call the visual consequence of ocular hypotension) just a bit - which is normal for me when I stretch after having sat still for too long - and instead of resolving the greyout continues. My field of view starts to fade in blotches, but I can still see - I realize that it's just in one eye. I close one, then the other, and now I know that the view from my left eye is fading.

I jump up and run to Eli's office, and by this time, my left eye view is almost completely blank, except for a space around the fovea, maybe 5° wide and 2° high. This makes sense - the foveal blood supply comes from the choroid, not the apparently blocked ophthalmic artery. The blankness is plainly visible as a flat gray. This is different from the scotoma of the migraine aura, which is as visible as the space behind my head. The boundary between the visible center and the blankness is shimmering, flickering, like the smoldering edge of slowly burning paper. Eli gets his ophthalmoscope to try and see what's happening, and the superior field starts to fade back into view.

It's then stable for about a minute, the inferior field is blank gray, and there's a smoldering horizontal boundary between the superior and inferior fields. I see some strange parafoveal phosphenes, like super-high contrast arcs. Eli is shining a light in my eye, and I'm shocked to realize that this bright light is totally failing to punch through the grayness. I wave my hand in the scotoma and though I can't see it, I feel like I can sense the motion.

The inferior nasal field returns, very subtly, so that I just realize it's back without noticing much about how it returns. It's patchy but quick - then the inferior temporal field returns. After this point, I can't find any other blind areas; everything has returned. In fact, I can't find any obvious differences between the two eyes, though at this time Eli is urging me to go to the ER to get examined. My heart is pounding and my head is starting to hurt. For the next 10-15 minutes, as I'm on my way to the hospital, I can see my pulse with the left eye, but then no more, and everything is back to normal.

Eli gets me in to see someone at MEEI, and I'm examined by an ophthalmology resident. The doctor pronounces this a case of ocular migraine, which as far as I understand means "we don't know, but everything looks ok".

Typical Wednesday afternoon. Hey, April is here!

**edit @ 16:21**

While I don't like the 'migraine' label, I guess I can't deny that there might be something to it. It is unknown what the proximal cause of a migraine is, though it's definitely associated with cortical spreading depression in the brain, the physiological correlate of a migraine aura; the current consensus seems to be that the CSD produces substances that inflame tissues in the brain, which then is perceived as pain, and which fits with the experience of headache beginning partway through the aura.

But what causes the CSD? One sure way to cause it is to deprive an area of cortex of blood - stroke causes CSD even in areas of cortex that still have blood supply but happen to be nearby the ischemic areas. So it could be that the aura/CSD is caused by a very local, transient ischemia. The ischemia can't be very large or long-lived because there don't tend to be other symptoms accompanying the well-described auras.

I would be happy if I could confirm that this episode is somehow related to the migraines, i.e. that I experienced a spasm of the ophthalmic artery of the same sort that I usually experience on a much smaller scale, and deeper in my brain, immediately preceding a migraine aura. I also do not feel much affection for this experience, in contrast to the fascinating auras - I hope this does not happen repeatedly, because I don't think it can be good for the retina to periodically starve it of oxygen.