Matt Jones wrote:
>> In article <Pine.SGI.3.94.961017082443.17491H-100000 at proteus> Joseph
> Strout, jstrout at ucsd.edu writes:
> >many other stimuli.) The cells are not activated in any coherent
> pattern,
> >so the result appears as random points of light.
>> I've "seen stars" on occassion just by standing up too quickly, with no
> physical jolt to my head at all. I think the two explanations above about
> firing of cells in visual cortex (and maybe other cells in the pathway
> between retina and cortex) are probably right on. The phenomenon can be
> caused by any unusual state change of the system: a blow to the head,
> transient anoxia (from standing up without taking a deep breath), from
> taking drugs like LSD, or whatever.
>> What I find really interesting is that it's not just random points of
> "light", It's randomly *moving* points of light. The stars sort of swim
> around in little wavy arcs. They appear to be generated at random
> locations in the visual field, then swim a little way, then fade out
> quickly, but not instantaneously. It's really pretty cool. So my theory
> about this is that we're not just "seeing" some neurons firing, but
> actually watching the propagation of activity in waves across fields of
> neurons through the tissue. As a thumbnail estimate, I'd say that each
> little star occupies maybe one tenth of one percent of my entire visual
> field, or less. They don't seem to change much in size as they swim
> around, suggesting that the propagating wave of activity involves an
> approximately constant number of neurons as it travels (maybe this is too
> naive).
>> So does anyone know how many neurons, or what fraction of the area of
> visual cortex, accounts for one tenth of one percent of the visual field?
> Is it just one tenth of one percent of visual cortex area? And how many
> neurons (principal, glutamatergic neurons) is that?
>> Interesting subject, seeing stars...
>> -Matt
>> P.S. - Does anybody else notice this movement, or is it just me? Also,
> has anybody noticed what happens when two stars cross paths? Do they
> annihilate each other (as many disturbances in excitable media do), or do
> they each just keep on going?
...your observations are =HOT!= ken collins
_____________________________________________________
People hate because they fear, and they fear because
they do not understand, and they do not understand
because hating is less work than understanding.
