<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div>I hate to jump into this, but...<div><br></div><div>Speaking as a true novice, I would like to point out that the neurogenesis that occurs on a daily basis is very specific to the dentate gyrus; if someone knows of "daily neurogenesis" elsewhere, I would like to hear about it. </div><div><br></div><div>This is not the same as learning in an ANN - these new neurons have a specific function, which some of the best minds in our field are currently trying to figure out <font class="Apple-style-span" color="#000000">(see </font><em style="text-decoration: inherit; "><font class="Apple-style-span" color="#000000"><span class="Apple-style-span" style="font-style: normal;">Aimone</span></font></em><font class="Apple-style-span" color="#000000">, J., </font><em style="text-decoration: inherit; "><font class="Apple-style-span" color="#000000"><span class="Apple-style-span" style="font-style: normal;">Wiles</span></font></em><font class="Apple-style-span" color="#000000">, J., & Gage, F. (2006). Potential role for adult neurogenesis in the encoding of time in new memories. Nature Neuroscience, 9(6), 723-727. for one example).</font></div><div><br></div><div>It is only if you don't have a good weight change rule (e.g., STDP) and/or you believe in localist encodings that you need neurogenesis to learn.</div><div><br></div><div>(shields up! ;-))</div><div><br></div><div>g.</div><div><br></div><div><div><div>On Sep 2, 2008, at 12:50 PM, Asim Roy wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> <div style="WORD-WRAP: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space"> <div><span class="Apple-style-span" style="TEXT-DECORATION: underline; -webkit-text-decorations-in-effect: underline">Asim Roy</span>: "a "blank slate" simply implies a network whose connection weights and other parameters have not been set yet -"<br><span class="281005119-02092008"><font face="Arial" color="#0000ff" size="2"> </font></span></div> <div dir="ltr"><span class="531280007-01092008"><strong><u>Jim Bower's response</u></strong>: </span>And, no such thing in biology, where development doesn't end and learning begins - it is continuous, and development probably recapitulating evolutionary history. Another reason why the mainstream ANN models make no sense.</div> <div dir="ltr"><font face="Arial" color="#0000ff" size="2"></font> </div> <div dir="ltr"><font face="Arial" color="#0000ff" size="2"></font> </div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff">Jim, would love to get some references for your statement:- "development probably recapitulating evolutionary history." This really is the kind of process in the brain that I am looking for. Just a few references would suffice.</font></span></div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff"></font></span> </div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff">By the way, learning takes place during development too. Just ask anyone in cognitive science. Development is not disassociated from learning. And ANN never implied learning begins after development. That's a misconception. </font></span></div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff"></font></span> </div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff">On the "blank slate" idea in ANN, just look at the phenomenon of adult neurogenesis. Our adult brains generate new cells in the thousands on a daily basis and they are part of the "blank slate" because they don't come with ready-made connections or anything. The process that you refer to as "<font color="#000000">development probably recapitulating evolutionary history" </font></font><font color="#0000ff">is called "learning" in ANN. It's that process that constructs networks out of these new cells and makes them operational.</font></span></div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff"></font></span> </div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff">Asim<span class="281005119-02092008"><font face="Arial" size="2"> Roy</font></span></font></span></div> <div dir="ltr"><span class="531280007-01092008"><font color="#0000ff"><span class="281005119-02092008"><font face="Arial" size="2">Arizona State University</font> </span></font></span></div> <blockquote dir="ltr" style="MARGIN-RIGHT: 0px"> <div><font face="Arial" color="#0000ff" size="2"></font> </div> <div><font face="Arial" color="#0000ff" size="2"></font> </div> <blockquote> <div class="OutlookMessageHeader" dir="ltr" align="left"><font face="Tahoma" size="2">-----Original Message-----<br><b>From:</b> comp-neuro-bounces@neuroinf.org [<a href="mailto:comp-neuro-bounces@neuroinf.org">mailto:comp-neuro-bounces@neuroinf.org</a>]<b>On Behalf Of </b>james bower<br><b>Sent:</b> Wednesday, August 27, 2008 9:05 AM<br><b>To:</b> CompNeuro List<br><b>Subject:</b> [Comp-neuro] Discussion - Kuhn - and brief comments<br><br></font></div> <div>A few brief comments -- given that school has started, and I now have to prepare to "influence" the latest next generation.</div> <div><br></div> <div>First a BIG POINT:</div> <div apple-content-edited="true"><span class="Apple-style-span" style="WORD-SPACING: 0px; FONT: 12px Helvetica; TEXT-TRANSFORM: none; COLOR: rgb(0,0,0); TEXT-INDENT: 0px; WHITE-SPACE: normal; LETTER-SPACING: normal; BORDER-COLLAPSE: separate; -webkit-text-decorations-in-effect: none; orphans: 2; widows: 2; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0"><span class="Apple-style-span" style="WORD-SPACING: 0px; FONT: 12px Helvetica; TEXT-TRANSFORM: none; COLOR: rgb(0,0,0); TEXT-INDENT: 0px; WHITE-SPACE: normal; LETTER-SPACING: normal; BORDER-COLLAPSE: separate; -webkit-text-decorations-in-effect: none; orphans: 2; widows: 2; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px"> <div style="WORD-WRAP: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space"> <div> <div> <div><br></div> <div>Klaus Stiefel: pre-paradigmatic " What he meant by that is a disagreement about the basic explainanda"</div> <div><br></div> <div>No, Kuhn was focused on process to quote: "the early developmental stages of most sciences (are) characterized by continual competition between a number of distinct views of nature, each partially derived from, and all roughly compatible with, the dictates of scientific observation and method, (In pre-paradigmatic science) what differentiates these various schools (is) not one or another failure of method - they are all "scientific" - but what we shall come to call their incommensurable ways of seeing the world and practicing science within it" (pg 4 The Structure of Scientific Revolution.) If this discussion over the last two months doesn't make it clear that, as a field, we currently have "incommensurate ways of seeing the world and practicing science within it" I don't know what does. Kuhn goes on to say: "Men (sic) whose research is based on shared paradigms are committed to the same rules and standards for scientific practice." Again, this discussion makes it pretty clear to me that we have not yet reached that point. In fact, (and I would say reflecting this fact) the kind of discussion we have been having here seldom ever happens as we are content (and being pre-paradigmatic can get away with) agreeing to not discuss what we don't agree on, another characteristic of pre-paradigmatic science -- and the reason I don't mind starting these discussions.</div> <div><br></div> <div>Bryan Bishop: "There's a few too many layers of folk psychology here,"</div> <div><br></div> <div>I agree, and have characterized all of biology as fundamentally folkloric in nature -- based on story telling, with few real definitions of anything. Something comp bio (neuro) will, I hope, eventually fix.</div> <div><br></div> <div><br></div> <div><br></div> <div>And on to the approaches we don't agree on:</div> <div><br></div> <div><span class="Apple-style-span" style="TEXT-DECORATION: underline">Bryan Bishop</span>: "I bet it becomes clear that trying to do "natural language processing" from statistical inferences doesn't get us as much hard science as the brain could provide."</div> <div><br></div> <div>Of course, I agree -- and also agree that this field continues to be distorted by what is essential snake oil we sell to the Department of Defense about how studying the brain will help win wars. This rather self serving commitment to "neuro-morphic engineering" as it is now called, has been distorting our science for a while. In the last 8 years even more dramatically. </div> <div><br></div> <div>Mario Negrello: "I'd say instead that some approaches gather more acolytes, and then overflow others in sheer voluminous quantity,"</div> <div><br></div> <div>Unfortunately, as just noted, very often related to who you are selling the science to (funders) and also, unfortunately, how 'easy' the methods are and therefore how many can jump on the bandwagon without much preparation (or even knowledge of the brain in this case) -- 20 years studying the realistic model of the Purkinje cell and counting. </div> <div><br></div> <div> <div><br></div> <div>Bard Ermentrout: " I suspect that it would be too hard to adjust parameters for realistic models "</div> <div><br></div> <div>Is hard bad? Or is the brain, in fact, hard?</div> <div><br></div></div> <div><br> <div apple-content-edited="true"> <div style="WORD-WRAP: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space"> <div> <div> <div><span class="Apple-style-span" style="TEXT-DECORATION: underline; -webkit-text-decorations-in-effect: underline">Igor Carron</span>: "The groundwork of theory as you put it has, in nuclear technology, always been a way to acquire and use experimental findings." <div><br></div>And this, in fact, is the value of theory -- not to capture 'truth' as many in comp neuro seem be believe, but to organize experimental studies -- the more the theory is removed from the actual structure of the brain - the more it exists by itself, disconnected from the ability to improve, or more importantly to refute it.</div> <div><br></div> <div><br></div> <div><span class="Apple-style-span" style="TEXT-DECORATION: underline; -webkit-text-decorations-in-effect: underline">Asim Roy</span>: "a "blank slate" simply implies a network whose connection weights and other parameters have not been set yet -"</div> <div><br></div> <div>And, no such thing in biology, where development doesn't end and learning begins - it is continuous, and development probably recapitulating evolutionary history. Another reason why the mainstream ANN models make no sense.</div> <div><br></div> <div><br></div> <div>Asim Roy: "Is there a way in computational neuroscience to verify any of these theories of learning? "</div> <div><br></div> <div>Wrong question.</div> <div><br></div> <div><br></div> <div>Axel Hutt: " can (neuro)biology really treat a population of some thousand elements ? "</div> <div><br></div> <div>We will need to figure out how - numerous groups are working on it.</div> <div><br></div> <div><br></div> <div>Anibalmastobiza: "cerebellum, usually considered as a center for motor processing and coordination just as it was for the basal ganglia that now we know that is also involve in cognition"</div> <div><br></div> <div>While I appreciate the support, I have another question for cognitive neuroscientists, how come anything that lights up in a brain scan becomes a "cognitive center" seems weird to me. </div> <div><br></div> <div><br></div> <div>Jim</div> <div><br></div> <div><br></div> <div><br></div> <div><br></div> <div><br></div></div></div></div></div></div> <div><br><br class="webkit-block-placeholder"></div> <div><br class="webkit-block-placeholder"></div> <div>==================================</div> <div><br class="webkit-block-placeholder"></div> <div>Dr. James M. Bower Ph.D.</div> <div><br></div> <div>Professor of Computational Neuroscience</div> <div><br></div> <div>Research Imaging Center</div> <div>University of Texas Health Science Center - </div> <div>- San Antonio</div> <div>8403 Floyd Curl Drive</div> <div>San Antonio Texas 78284-6240</div> <div><br></div> <div>Main Number: 210- 567-8100</div> <div>Fax: 210 567-8152</div>Mobile: 210-382-0553 <div><br> <div> <div>CONFIDENTIAL NOTICE:<br>The contents of this email and any attachments to it may be privileged or<br>contain privileged and confidential information. This information is only<br>for the viewing or use of the intended recipient. 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