{"id":101,"date":"2013-06-13T00:22:15","date_gmt":"2013-06-12T22:22:15","guid":{"rendered":"http:\/\/javierorlandi.com\/?p=101"},"modified":"2015-09-30T18:44:29","modified_gmt":"2015-09-30T16:44:29","slug":"the-emergence-of-spontaneous-activity-in-neuronal-cultures-coherence-from-noise-2","status":"publish","type":"post","link":"http:\/\/javierorlandi.com\/?p=101","title":{"rendered":"The emergence of spontaneous activity in neuronal cultures, coherence from noise"},"content":{"rendered":"<p style=\"text-align: justify;\">Barcelona Computational and Systems Neuroscience (BARCCSYN)<br \/>\nBarcelona, Spain. 13-14 June <strong>2013<\/strong><\/p>\n<p><!--more--><\/p>\n<p style=\"text-align: justify;\"><strong>Abstract:<\/strong><\/p>\n<p style=\"text-align: justify;\">When neurons are grown in vitro and left unperturbed, they create their own network of \u00a0connections and eventually reach a state where they fire simultaneously in a strikingly regular \u00a0collective pattern of nearly periodic bursts [1]. Even though the spontaneous activity of \u00a0neuronal networks is widely recognized as a fundamental problem in neuroscience, the \u00a0mechanisms governing these bursts of spontaneous activity are not well understood. In \u00a0neuronal cultures many conflicting views coexist, from burst initiation zones in 1D systems [2], to leading neurons [3] and network interactions [4] amongst others. Here we give new insights\u00a0on the emergence of spontaneous activity in two-dimensional neuronal cultures and tackle \u00a0this problem with two complementary approaches. Using high-speed calcium imaging\u00a0techniques in cultures derived from cortical neurons of embryonic rat brains, we show that the\u00a0collective bursts of activity are in fact propagating waves of activity that are locally nucleated.<\/p>\n<p style=\"text-align: justify;\">The nucleation develops in specific sites of the cultures that are independent of each other\u00a0and have a well defined size. With in silico modelling, we elucidate the origin of the bursting\u00a0activity in terms of a new phenomenon that we call noise focusing, a fast nucleation\u00a0mechanism that relies both on detailed network topology and on the neurons\u2019 integrate-andfire dynamics. The phenomenon consists of a selective, highly directional noise amplification\u00a0mechanism that drives activity avalanches towards a few focal points that act as noise\u00a0attractors. The resulting scenario challenges common understanding of neuronal cultures\u00a0while providing a simple physical explanation of all the existing data with no appeal to any\u00a0biological guidance of the network architecture.<\/p>\n<ol>\n<li>Eckmann JP, Feinerman O, Gruendlinger L, Moses E, Soriano J, Tlusty T: The physics of living\u00a0neural networks. Phys Rep 2007, 449:54-76.<\/li>\n<li><span style=\"text-align: justify;\">Alvarez-Lacalle E, Moses E: Slow and fast pulses in 1-D cultures of excitatory neurons. J\u00a0<\/span>Comput Neurosci 2009, 26:475\u2013493.<\/li>\n<li><span style=\"text-align: justify;\">Eckmann JP, Jacobi S, Marom S, Moses E, Zbinden C: Leader neurons in population bursts of\u00a0<\/span>2D living neural networks. New J Phys 2008, 10:015011.<\/li>\n<li><span style=\"text-align: justify;\">Eytan D, Marom S: Dynamics and effective topology underlying synchronization in networks\u00a0<\/span>of cortical neurons. J Neurosci 2006, 26:8465\u20138476<\/li>\n<\/ol>\n<p style=\"text-align: center;\">[\u00a0<a href=\"http:\/\/www.crm.cat\/en\/Activities\/Pages\/ActivityFoldersAndPages\/Curs%202012-2013\/BARCSYN2013\/BARCSYN2013.aspx\">web<\/a>\u00a0]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Barcelona Computational and Systems Neuroscience (BARCCSYN) Barcelona, Spain. 13-14 June 2013<\/p>\n","protected":false},"author":1,"featured_media":102,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[8],"tags":[],"_links":{"self":[{"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/posts\/101"}],"collection":[{"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=101"}],"version-history":[{"count":5,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/posts\/101\/revisions"}],"predecessor-version":[{"id":475,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/posts\/101\/revisions\/475"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=\/wp\/v2\/media\/102"}],"wp:attachment":[{"href":"http:\/\/javierorlandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=101"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/javierorlandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}