<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif">On Sun, Jan 24, 2016 at 7:49 AM, Anders Sandberg </span><span dir="ltr" style="font-family:arial,sans-serif"><<a href="mailto:anders@aleph.se" target="_blank">anders@aleph.se</a>></span><span style="font-family:arial,sans-serif"> wrote:</span><br></div><div class="gmail_extra"><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
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<div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Neat. Generally LTP is seen as the
first of a longer cascade of fixation of memories. Most research
has been about cellular skeleton changes, but perineuronal nets
might also work. <br>
It might actually be a good experiment for cryonics to see what
the process does to these nets. (I think John mixed up the
perioneuronal net (protein networks) with perineuronal space in
the sleep reference. )<br></div></div></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"></div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">As I understand it </div>the extracellular matrix <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">is</div> the space between brain cells<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> and that is where the </div><font face="arial, helvetica, sans-serif">perineuronal net <div class="gmail_default" style="display:inline">is located along with a lot of fluid, and the volume of the </div></font>extracellular matrix <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">changes a great deal between sleep and wakefulness so the net must be tough enough to resist damage even when things get crowded. But I'm no expert on this so I may have misunderstood. </div></font></div><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Incidentally, the Sejnowski lab had a nice result on the
distribution of synaptic strengths:<br>
<a href="http://papers.cnl.salk.edu/index.php?SearchText=Bartol%2C%20T.%20M.%20Jr.%20Bromer%2C%20C.%20Kinney%2C%20J.%20P.%20Chirillo%2C%20M.%20A.%20Bourne%2C%20J.%20N.%20Harris%2C%20K.%20M.%20Sejnowski%2C%20T.%20J." style="margin:0px;padding:0px;border:0px;outline:0px;font-size:12.8px;vertical-align:baseline;text-decoration:none;color:gray;font-weight:bold;font-family:Helvetica,Arial,'Liberation Sans',FreeSans,sans-serif;font-style:normal;font-variant:normal;letter-spacing:normal;line-height:19.2px;text-align:left;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background:rgb(255,255,255)" target="_blank">Bartol, T. M. Jr. Bromer, C.
Kinney, J. P. Chirillo, M. A. Bourne, J. N. Harris, K. M.
Sejnowski, T. J.</a><span style="color:rgb(0,0,0);font-family:Helvetica,Arial,'Liberation Sans',FreeSans,sans-serif;font-size:12.8px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:19.2px;text-align:left;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important;background-color:rgb(255,255,255)"><span> </span>Nanoconnectomic
upper bound on the variability of synaptic plasticity, eLife,
4:e10778, 2015<span> </span></span><br>
</div>
<a href="http://papers.cnl.salk.edu/PDFs/Nanoconnectomic%20upper%20bound%20on%20the%20variability%20of%20synaptic%20plasticity%202015-4475.pdf" target="_blank">http://papers.cnl.salk.edu/PDFs/Nanoconnectomic%20upper%20bound%20on%20the%20variability%20of%20synaptic%20plasticity%202015-4475.pdf</a><br>
They show that each synapse stores at most about 4.7 bits. While
their press material claims this is "an order of magnitude more"
than previous estimates, the actual estimate most people have been
doing is about one bit, so the difference isn't dramatic. But doing
nanoconnectomics is an awesome method.</div></blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">I wish we knew how much redundancy there is in the brain, biological operations are not nearly as reliable as the electronic operations we use in computers so I would guess there must be a lot of </div><font face="arial, helvetica, sans-serif">redundancy</font><div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif"> to ensure accuracy.</font></div></font></div><div><div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif" size="4"><br></font></div></div><div><div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif" size="4"> John K Clark</font></div></div><div><div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif" size="4"><br></font></div></div><div><div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif" size="4"> </font></div></div><div><br></div><div> </div></div><br></div></div>