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          <p style="text-align:center"><font size="4"><a href="https://84454458.streak-link.com/Cu_jCCG2NjDCvG8wmgY2VS0k/https%3A%2F%2Fwww.wwtns.online" target="_blank"></a></font></p></div></div></div></div></blockquote></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div class="gmail_quote"><div dir="ltr"><p style="text-align:center"><font size="4"><a href="https://streaklinks.com/A9c7PbbpKY7PxB6PaAJWGD3-/https%3A%2F%2Fwww.wwtns.online" target="_blank">https://www.wwtns.online</a>
              - on twitter: wwtns@TheoreticalWide - on Youtube</font></p></div></div></div></div></blockquote><div style="text-align:center"><br></div><div style="text-align:center"><font size="4">New on the VVTNS YouTube Channel </font></div><div style="text-align:center"><font size="4"><a href="https://www.wwtns.online/past-seminars-2025-2026" target="_blank">https://www.wwtns.online/past-seminars-2025-2026</a></font></div><div style="text-align:center"><font size="4"><br></font></div><div style="text-align:center"><div><span style="font-family:spinnaker,sans-serif;font-size:20px"><b><font color="#000000">Computation Through Neuronal-Synaptic Dynamics</font></b></span></div><div><br></div><div><span style="color:rgb(13,13,13);font-family:Roboto,Noto,sans-serif;text-align:start"><font size="4">lecture delivered on January 14,  2026  by</font></span></div><div><p style="background:transparent;border:0px;outline:0px;padding:0px;vertical-align:baseline;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;font-size-adjust:none;font-kerning:auto;font-feature-settings:normal;font-stretch:normal;font-size:18px;line-height:1.6em;font-family:spinnaker,sans-serif;margin:0px"><span style="background:transparent;border:0px;margin:0px;outline:0px;padding:0px;vertical-align:baseline;font-family:helvetica-w01-roman,helvetica-w02-roman,helvetica-lt-w10-roman,sans-serif"><span style="background:transparent;border:0px;margin:0px;outline:0px;padding:0px;vertical-align:baseline"><span style="background:transparent;border:0px;margin:0px;outline:0px;padding:0px;vertical-align:baseline"><font color="#000000">David Clark</font></span></span></span></p><p style="background:transparent;border:0px;outline:0px;padding:0px;vertical-align:baseline;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;font-size-adjust:none;font-kerning:auto;font-feature-settings:normal;font-stretch:normal;font-size:18px;line-height:1.6em;font-family:spinnaker,sans-serif;margin:0px"><span style="background:transparent;border:0px;margin:0px;outline:0px;padding:0px;vertical-align:baseline;font-family:helvetica-w01-roman,helvetica-w02-roman,helvetica-lt-w10-roman,sans-serif"><span style="background:transparent;border:0px;margin:0px;outline:0px;padding:0px;vertical-align:baseline"><span style="background:transparent;border:0px;margin:0px;outline:0px;padding:0px;vertical-align:baseline"><font color="#000000">Kempner Institute </font></span></span></span><span style="color:rgb(0,0,0);background-color:transparent;font-family:helvetica-w01-roman,helvetica-w02-roman,helvetica-lt-w10-roman,sans-serif">at Harvard University</span></p></div><div><br></div><div><font color="#000000"><br></font></div></div><div style="text-align:left"><font color="#000000"><b>Abstract: </b><span style="font-family:spinnaker,sans-serif;font-size:14px;text-align:justify">Computations in neural circuits are often construed as being implemented through the coordinated dynamics of neurons. In this picture, the role of synaptic connectivity is to sculpt neuronal dynamics to implement computations of interest. Of course, synapses are not static but change on a variety of timescales, including fast timescales comparable to those of neurons. Thus, a more accurate view of computation in neural circuits may involve the coupled dynamics of neurons and synapses. This form of computation is closer to what is implemented by Transformers via an equivalence between ongoing synaptic plasticity and self-attention. I  will first describe a nonlinear recurrent neural-network model with ongoing Hebbian dynamics of “fast” synapses atop unstructured “slow” synapses. I will then describe two computations implemented through neuronal-synaptic dynamics, which can be studied in this model using techniques including dynamical mean-field theory and random-matrix theory. First, there exists a novel phase termed “freezable chaos” in which a stable fixed point of neuronal dynamics is continuously destabilized by synaptic dynamics. This allows for the creation of a stable fixed point at any neuronal state visited by the network by halting synaptic plasticity. Second, I will describe an effect termed “persistent oscillations” in which, following stimulation by a periodic signal, a plastic network continues to autonomously reproduce a similar signal for a duration exceeding any intrinsic timescale in the system. Thus, ongoing Hebbian plasticity can provide a dynamic form of working memory, complementing the static form provided by freezable chaos. Ongoing experimental work suggests that this effect is realized in cortical organoids. Overall, this line of work suggests that synapses should be promoted to first-class dynamical degrees of freedom in our conceptual understanding of neural-circuit function.</span></font></div><div style="text-align:center"><br></div><div style="text-align:center"><p style="text-align:left;background:transparent;border:0px;outline:0px;padding:0px;vertical-align:baseline;font-variant-numeric:normal;font-variant-east-asian:normal;font-variant-alternates:normal;font-size-adjust:none;font-kerning:auto;font-feature-settings:normal;font-stretch:normal;line-height:1.6em;font-family:spinnaker,sans-serif;margin:0px"><i style="background-color:transparent;font-family:Arial,Helvetica,sans-serif;color:rgb(80,0,80)"><font color="#000000"><span style="font-family:helvetica-w01-light,helvetica-w02-light,sans-serif;text-align:justify"><b>About VVTNS :</b> Launched as the World Wide  Theoretical Neuroscience Seminar (WWTN</span><span style="font-family:helvetica-w01-light,helvetica-w02-light,sans-serif;text-align:justify">S) in N</span></font><span style="color:rgb(0,0,0);font-family:helvetica-w01-light,helvetica-w02-light,sans-serif;text-align:justify">ovember 2020 and renamed in homage to Carl van Vreeswijk in Memoriam (April 20, 2022), Speakers have the occasion to talk about theoretical aspects of their work which cannot be discussed in a setting where the majority of the audience consists of experimentalists. The seminars, </span></i><i style="background-color:transparent;font-family:Arial,Helvetica,sans-serif;color:rgb(80,0,80)"><span style="color:rgb(0,0,0);font-family:helvetica-w01-light,helvetica-w02-light,sans-serif;text-align:justify">held on Wednesdays at 11 am ET,</span></i><i style="background-color:transparent;font-family:Arial,Helvetica,sans-serif;color:rgb(80,0,80)"><span style="color:rgb(0,0,0);font-family:helvetica-w01-light,helvetica-w02-light,sans-serif;text-align:justify">  are 45-50 min long followed by a discussion. The talks are recorded with authorization of the speaker and are available to everybody on our YouTube channel.</span></i></p></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><br></div></div></div></div></div></div><div hspace="streak-pt-mark" style="max-height:1px"><img alt="" style="width:0px;max-height:0px;overflow:hidden" src="https://mailfoogae.appspot.com/t?sender=aZGhhbnNlbDBAZ21haWwuY29t&type=zerocontent&guid=bc8ff73d-ffb4-4f9e-9ff6-05e964f1bb46"><font color="#ffffff" size="1">ᐧ</font></div>