Daniel Dombeck, Place Cells Hippocampus
<p>Jan 07, 2016 05:58 PM this YouTube is beautfully clear.</p>
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asst prof at NW.
mouse VR.</p>
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HM Henry Molaison... studied in 1950s...
had epilepsy in mid teen years.
early 20s... debilitated...
did bilat MTL removal... did not get rid of sz.</p>
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interviewd by Brenda Milner...</p>
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looked normal and had nl critical thinking and intelligence but could not form new memorys
anterograde amnesia.</p>
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HC required for memory formation and recent memory recall.
work in 1950s. this focused subseq work on HC = hippocampus.</p>
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model system: mouse has 9 mm brain wide.</p>
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Morris water maze...</p>
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search for hidden platform...
at beginning do random search... see landmarks in room.
after several days they go straight for it.
but if you inactivate HC before or immed after then cannot do it (same as HM)</p>
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*
shows place fields and place cells... they tile whole environment.
1/4 to 1/3 of cells in HC are place cells.</p>
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get global remapping when rodent placed in new enviro
and then orig place fields return in original enviro...
cognit map of enviro...
firing patterns of these cells gives us a view into cognition (how do they form)</p>
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can now image these cells;
need lots of mechanical stability...
make a miniature scope and head mount it...</p>
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or fix animal to scope with head place.</p>
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see Dombeck in Neuron in 2007.
see Uexkull in 1937 with snails!!!</p>
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in plane motion is only 3 to 5 mcrons.
and can do motion correct algo. with HMM.</p>
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acquire at 4 to 8 frames per sec.
get good stability.</p>
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use fast CCD camera...
most of mvmt is < 30 hz !!!
adn improved fluorphors.
removes in frame distortion.</p>
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VR enviro: in front of huge monitor with VR environment.
use Quake 2 video game engine!!!
HC activated similar to freely moving animals.</p>
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look at correl of firing of neurons and position on the 180 cm virtual track.</p>
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areplace cells in HC spatially organized.
random vs spatial.
RANDOM is the answer... there is NO organization (they are NOT spatially organized.)
(unlike the motor cortex)</p>
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putting cells close together does minimze communic energy and wiring and transit time.</p>
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(this is unlike motor cortex... keep eg cells that control forelimb close together)</p>
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unlike HC: used by Place cells (for location) but also when why and where.
random network is best to maximize storage capacity.</p>
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