<div dir="ltr">FYI<div>'Dendritic action potentials' just joined 'somatic action potentials'. The game just changed.</div><div><br></div><div><div>==============================<wbr>==============</div><div>Moore, J.J., Ravassard, P.M., Ho, D., Acharya, L., Kees, A.L., Vuong, C., and Mehta, M.R. (2017). Dynamics of cortical dendritic membrane potential and spikes in freely behaving rats. Science.<br></div><div><br></div><div>Earlier Arxiv version <a href="http://biorxiv.org/content/early/2016/12/28/096941" target="_blank">http://biorxiv.org/content/ear<wbr>ly/2016/12/28/096941</a></div><div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">See <a href="http://science.sciencemag.org/content/early/2017/03/08/science.aaj1497" target="_blank">http://science.sciencemag.<wbr>org/content/early/2017/03/08/s<wbr>cience.aaj1497</a></div><div style="font-size:12.8px">and commentary </div><div><span style="color:rgb(0,0,0);font-family:marrsans,helvetica,"arial black",arial,sans-serif;letter-spacing:-0.02em">"Why our brains may be 100 times more powerful than believed"</span><br></div><div style="font-size:12.8px">here: <a href="http://newatlas.com/brains-more-powerful/48357/" style="font-size:12.8px" target="_blank">http://newatlas.com/brai<wbr>ns-more-powerful/48357/</a><br></div><div style="font-size:12.8px">==============================<wbr>======================</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Check out the video of the DAP waveform in the supplementary material.</div><div style="font-size:12.8px"><div style="font-size:12.8px"><a href="http://science.sciencemag.org/content/suppl/2017/03/08/science.aaj1497.DC1" target="_blank">http://science.sciencemag.org/<wbr>content/suppl/2017/03/08/<wbr>science.aaj1497.DC1</a><br></div><div><br></div></div><div style="font-size:12.8px"><span style="font-size:12.8px">Neocortical sub- and suprathreshold dendritic membrane potential (DMP) breaking out into localised firing within the dendrite structure. Dendrite firing has been observed for a long time, but this is the first time anyone has seriously accessed its origins and correlated it with behaviour. Collectively the DMP are very strong (as represented by voltage measured in tissue: Higher than somatic action potentials!) and much faster. This is because neural tissue is 90% dendritic and there are collosal numbers of post-synaptic densities (synapses).</span><br></div></div></div><div style="font-size:12.8px"><span style="font-size:12.8px"><br></span></div><div style="font-size:12.8px"><span style="font-size:12.8px">Talking about action potentials just got orders of magnitude more involved.</span></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">cheers</div><div style="font-size:12.8px"><br></div><div>Colin</div><div><br></div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Mar 16, 2017 at 7:40 AM, William Flynn Wallace <span dir="ltr"><<a href="mailto:foozler83@gmail.com" target="_blank">foozler83@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:#000000">addition - see at bottom</div><div class="gmail_extra"><br><div class="gmail_quote"><span class="">On Wed, Mar 15, 2017 at 3:09 PM, William Flynn Wallace <span dir="ltr"><<a href="mailto:foozler83@gmail.com" target="_blank">foozler83@gmail.com</a>></span> wrote:<br></span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:#000000"><br></div><div class="gmail_extra"><br><div class="gmail_quote"><span class=""><div><div class="m_-7147128270103446851h5">On Wed, Mar 15, 2017 at 2:26 PM, Adrian Tymes <span dir="ltr"><<a href="mailto:atymes@gmail.com" target="_blank">atymes@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto"><span><div>On Mar 15, 2017 11:00 AM, "William Flynn Wallace" <<a href="mailto:foozler83@gmail.com" target="_blank">foozler83@gmail.com</a>> wrote:<div class="gmail_extra"><div class="gmail_quote"><blockquote class="m_-7147128270103446851m_-3926913758068364148m_6814686469066804297m_6202488792997825301quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div class="m_-7147128270103446851m_-3926913758068364148m_6814686469066804297m_6202488792997825301quoted-text">On Wed, Mar 15, 2017 at 12:29 AM, Adrian Tymes <span dir="ltr"><<a href="mailto:atymes@gmail.com" target="_blank">atymes@gmail.com</a>></span> wrote:<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">At any given instant, a neuron may either be firing or have a time<br>
until next firing - but a firing is a (mostly) discrete event, with<br>
one firing distinct from the next.<br>
<br>
If it was not distinct - if it was "always firing" - then there would<br>
be no such thing as "speed" of firing. Rather than toggle on then off<br>
at various rates, it would simply be always on.<br></blockquote><div><br></div></div><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">-------------</div><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">There is a great deal of controversy about rate of firing, from about 1 every 6 seconds to 200 per second, up to a couple of thousand at the fastest (for cortical neurons). By always firing I meant only that it never rested more than a few seconds at the very most. Yes, discrete - absolute refractory period.</div></div></div></div></blockquote></div></div></div><div dir="auto"><br></div></span><div dir="auto">Right. And during that refractory period, the output is 0, regardless of how long it will be or has been to the next/previous firing.</div><span><div dir="auto"><br></div><div dir="auto"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="m_-7147128270103446851m_-3926913758068364148m_6814686469066804297m_6202488792997825301quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">So, again, that gives three states - not changing speed, slowing, increasing<br></div></div></div></div></blockquote></div></div></div><div dir="auto"><br></div></span><div dir="auto">No, two states: firing, or between firings.</div><div dir="auto"><br></div><div dir="auto">You are declaring the acceleration to be a state, when the state is more like the current position, and the simplification is that most ANNs don't even consider velocity let alone acceleration.</div></div></blockquote></div></div><div><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">-------------------</div><br></div></span><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><span class="">OK, I think we are in agreement: you and the ANN at looking at the state of the neuron at a fixed point in time, and I am looking at it over a period of time. Maybe we need to look at both to understand the neuron</span><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0);display:inline">.</div></div></div></div></div></blockquote><div><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">addition - come to think of it, whether the neuron is firing or not at a specific point in time, is a function of where on its body you measure the chemical exchange; we know that the spike travels the length of the cell body, a traveling wave, such that at the receiving end - the dendrite - you can measure the influx of ions into the body, whereas at its opposite end nothing is happening yet. Maybe this makes no difference. What do I know?</div><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0);display:inline"></div></div></div></div></div></blockquote><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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