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ref: -2011 tags: HiLo speckle imaging confocal boston university optical sectioning date: 02-19-2019 06:18 gmt revision:2 [1] [0] [head]

PMID-21280920 Optically sectioned in vivo imaging with speckle illumination HiLo microscopy

  • Ah, brilliant! Illuminate a sample with a speckle pattern from a laser, and use this to optically section the data -- the contrast of the speckle pattern shows how in focus the sample is.
    • Hanece, the contrast indicates the in-focus vs out-of-focus ratio in a region.
  • The speckle statistics are invariant even in a scattering media, as scattering only further randomizes an already random laser phase front. (Within some limits.)
  • HiLo microscopy involves illuminating with a speckle pattern, then illuminating with standard uniform illumination, resulting in a diffraction-limited optically sectioned image. PMID-18709098
  • Algorithm is :
    • Take the speckle image and subtract the uniform image δI\delta I
    • Bandpass δI\delta I
    • Measure the standard deviation of the δI\delta I to get a weighting function C δs 2C^2_{\delta s}
    • Debias this estimate based on sensor..
    • Generate low-passed image from the weighted uniform image, LP[C δsI u] LP[C_{\delta s} I_u] , and high-pass from the difference HP=1LPHP = 1 - LP
    • Resultand image is a weighted sum of highpassed and lowpassed images.
  • Looks about as good as confocal.
  • Cited by...

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ref: Friston-2002.1 tags: neuroscience philosophy feedback top-down sensory integration inference date: 10-25-2011 23:24 gmt revision:0 [head]

PMID-12450490 Functional integration and inference in the brain

  • Extra-classical tuning: tuning is dependent on behavioral context (motor) or stimulus context (sensory). Author proposes that neuroimaging can be used to investigate it in humans.
  • "Information theory can, in principle, proceed using only forward connections. However, it turns out that this is only possible when processes generating sensory inputs are invertible and independent. Invertibility is precluded when the cause of a percept and the context in which it is engendered interact." -- proof? citations? Makes sense though.
  • Argues for the rather simplistic proof of backward connections via neuroimaging..

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ref: -0 tags: rap poem life philosophy date: 04-07-2011 15:39 gmt revision:1 [0] [head]

so son why you looking so glum
why you not making that symbol with your index finger and thumb?
yea boy i know she couldn't kickit for real
true true puddin, if fun were a sale then she got quite a steal

the thing about the brain is with physical consequence
get computed with aplomb, clarity and consonance
when emotional matters get sucked into the fray
only a fool will guess where the causality will stray

it's almost fucking impossible to disentangle yourself
which is why im yappin to you rather than to cough cough to myself
dissatisfaction with her life is only slightly attached to angst in yer life
but blaming yourself is not what she did, so don't do it. 

externalize events, it's a common adult strategy
makes you feel a lot better irrespective of causality
titrating the blame like ah chemistry class
it's like the assholes are those who don't look at their own ass

speakin of which, point your telescope over there, 
no not the squirrel, check the thing that fills out the chair
now amusements can be had, amusements are given
the butcher is calling, high time to make a killin

you don't need to go to walking the Walden like Thoreau
to pick up the coinage that self questioning will throw
those who fail this will be a needle-nosed stasis
while you me and charley will be making a praxis

alright my brother time to show that squirrel who's bonafide
self-bootstrapping is best done while physically occupied. 

just having some fun :-)