Microscopy: Miniature Microscopes for Deep Tissue Imaging (Mark Schnitzer)

<p>Jun 08, 2015 03:46 PM &nbsp;iBioEducation &nbsp;38 minute video: &nbsp;excellent intro to Mark's work.</p>

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pub Nov 2013;</p>

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100B neurons; &nbsp;100 tr synapses</p>

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what are large-scale patterns of activity;</p>

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watch cells firing in large populations;</p>

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freely moving subjects....</p>

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how to do deep tissues in vivo;</p>

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light scattering is problem &nbsp;(not absorption)</p>

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confocal: &nbsp;150 microns depth</p>

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2P microsc: &nbsp;500 to 700 microns;</p>

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we do microendoscopy...</p>

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shows 1000 micron &nbsp;on penny

and one that is 350 microns &nbsp;on dime...</p>

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capillary flood flow in HC CA1...</p>

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rodent, live: &nbsp;fluor: &nbsp;can see indiv &nbsp;RBCs &nbsp;single file!!! &nbsp;and now higher...</p>

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see capil &nbsp;flow in CA1 &nbsp;&nbsp;broader than diam of capillary &nbsp;(rbc is abt 8 microns; &nbsp;actually 7.5)

they get squished in transit;</p>

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can do time-lapse over 1 year;</p>

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each scope is &nbsp;2.5 grams &nbsp;2 photon M</p>

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and high speed &nbsp;1.1 gram epi-fluor scope..</p>

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2 forms of fluor microenoscopy...</p>

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Jurgen Jung did this &nbsp;here...</p>

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epi-fluor: &nbsp;&nbsp;fast, full frame; &nbsp;mercury arc lamp... &nbsp;

100 hz &nbsp;and up to one khz...

but &nbsp;cannot get &nbsp;3d image stacks</p>

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laser-scanning 2photon = 2PM</p>

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it scans... can get 3d optical sectioning...

can park probe: &nbsp;then go 650 microns in depth into the tissue; &nbsp;from face of probe;

can get focal excitation;</p>

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GRIN &nbsp;is gradient refrac index &nbsp;&nbsp;one micron.</p>

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shows &nbsp;doublet scopes and triplets &nbsp;(colinear, sequential)</p>

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we have hundreds of these... economy of scale...</p>

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shows sarcomere contralie dynamics...

collab with Scott Delp;</p>

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uses in humans and in mice</p>

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see striations in muscle</p>

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look at glioma &nbsp;in &nbsp;tumor angiogenesis;</p>

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HC &nbsp;in mice &nbsp;CA1 &nbsp;total depth 530 microns...

CA1 &nbsp;pyram &nbsp;neurons...

input from DG;</p>

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do the &nbsp;dendrites of CA1 pyrams &nbsp;remodel? &nbsp;&nbsp;NO &nbsp;&nbsp;(no change)

(ie no changes in dendrites but there are changes in dendritic spines)</p>

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can see spines....</p>

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&nbsp;next; &nbsp;awake, behaving mice *</p>

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approach head 1: &nbsp;head-fixed &nbsp;but restricts behavior;</p>

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&nbsp;la Tank lab: &nbsp;&nbsp;can run on Tank ball;

using 2PM;</p>

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looks at Bergmann glia in cerebellum...gap junction coupled &nbsp;in glia; &nbsp;cells light up when running

label astrocytes...</p>

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tiny &nbsp;scopes &nbsp;born on the head; &nbsp;miniature scope;</p>

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freely behaving; &nbsp;up to 100 hz

one photon imaging...

long expts;</p>

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chronic implanted;</p>

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collab Oleg Solgard; &nbsp;&nbsp;2PM...</p>

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capill flow speeds;</p>

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but can use &nbsp;integrated &nbsp;CMOS &nbsp;5 mm inside package...</p>

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miniature scope &nbsp;(Mark has compnay)</p>

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Abbas El Gamal &nbsp;collab...</p>

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CMOS camera; &nbsp;has illumination;</p>

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shows microcirc &nbsp;in &nbsp;cerebellum...</p>

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cerebellar cortex... &nbsp;up to 100 hz...</p>

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speed of flow in caps;</p>

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neuronal dynamics</p>

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Yaniv Ziv and Laurie Burns...</p>

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CA1 &nbsp;&nbsp;viral vector &nbsp;Gcamp3 &nbsp;&nbsp;2x &nbsp;RT.</p>

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600 CA1 neurons tracked; &nbsp;get temp &nbsp;dynamics;</p>

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long periods of quiescence &nbsp;but occas activity;</p>

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HC &nbsp;place cells encode &nbsp;spatial memroies...</p>

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cell 159 &nbsp;lights up in upper L corner of cage...

remapping of plac efields...</p>

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could also use scope for imaging diagnostics...</p>

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