{"id":18,"date":"2011-01-24T08:00:41","date_gmt":"2011-01-24T07:00:41","guid":{"rendered":"http:\/\/blog-lecerveau.mcgill.ca\/?p=187"},"modified":"2022-01-04T21:06:25","modified_gmt":"2022-01-04T20:06:25","slug":"lhippocampe-entier-revele-ses-secrets","status":"publish","type":"post","link":"https:\/\/www.blog-lecerveau.org\/debutant\/2011\/01\/24\/lhippocampe-entier-revele-ses-secrets\/","title":{"rendered":"L\u2019hippocampe entier r\u00e9v\u00e8le ses secrets"},"content":{"rendered":"<p><img loading=\"lazy\" class=\"alignleft size-full wp-image-271\" src=\"https:\/\/www.blog-lecerveau.org\/wp-content\/uploads\/Theta-wave.jpg\" alt=\"Theta-wave\" width=\"110\" height=\"110\" \/>Il arrive parfois que des d\u00e9couvertes scientifiques importantes ne soient pas tant le fruit d\u2019une exp\u00e9rience particuli\u00e8re, mais du long travail pr\u00e9alable pour mettre au point le protocole exp\u00e9rimental. C\u2019est le cas d\u2019une \u00e9tude de Sylvain Williams publi\u00e9e en novembre 2009 dans Nature Neuroscience. Pendant des ann\u00e9es, Williams et ses collaborateurs ont raffin\u00e9 une technique permettant d\u2019enregistrer l\u2019activit\u00e9 neuronale dans un <a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/i\/i_07\/i_07_cr\/i_07_cr_tra\/i_07_cr_tra.html#2\"><span style=\"color: #008080;\">hippocampe <\/span><\/a>entier de rat conserv\u00e9 in vitro.<!--more--><\/p>\n<p>C\u2019est que la technique classique, celle o\u00f9 l\u2019on enregistre l\u2019activit\u00e9 des neurones dans une mince tranche d\u2019hippocampe, est beaucoup plus accessible. Mais elle d\u00e9truit in\u00e9vitablement \u00e9norm\u00e9ment de circuits internes \u00e0 l\u2019hippocampe, tous les axones qui voyagent perpendiculairement \u00e0 la tranche, par exemple.<\/p>\n<p>Par \u00e9tonnant que d\u00e8s les premiers enregistrements dans l\u2019hippocampe entier, l\u2019\u00e9quipe de Williams a bris\u00e9 un dogme vieux de plusieurs d\u00e9cennies\u00a0: le <a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/a\/a_11\/a_11_p\/a_11_p_cyc\/a_11_p_cyc.html\"><span style=\"color: #ff0000;\">rythme Th\u00eata<\/span><\/a>, rythme majeur de d\u00e9charge des neurones de l\u2019hippocampe, ne provient pas n\u00e9cessairement d\u2019une r\u00e9gion ext\u00e9rieure (le septum) comme on l\u2019avait toujours cru, mais peut provenir\u00a0de l\u2019hippocampe lui-m\u00eame !<\/p>\n<p>Voil\u00e0 ce que des centaines d\u2019\u00e9tudes avec des tranches d\u2019hippocampes n\u2019avaient pas pu observer et qui a \u00e9t\u00e9 d\u00e9montr\u00e9 clairement dans cette exp\u00e9rience. Quand on sait l\u2019importance primordiale des rythmes Th\u00eata pour <a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/d\/d_07\/d_07_p\/d_07_p_tra\/d_07_p_tra.html\"><span style=\"color: #ff9900;\">l\u2019apprentissage et la m\u00e9moire<\/span><\/a>, savoir que ce rythme <a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/d\/d_11\/d_11_cl\/d_11_cl_cyc\/d_11_cl_cyc.html#2\"><span style=\"color: #ff9900;\">peut \u00e9merger de mani\u00e8re endog<\/span><span style=\"color: #ff9900;\">\u00e8ne<\/span> <\/a>dans l\u2019hippocampe, et m\u00eame sp\u00e9cifiquement dans\u00a0<a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/a\/a_07\/a_07_cl\/a_07_cl_tra\/a_07_cl_tra.html\"><span style=\"color: #ff0000;\">sa sous-r\u00e9gion CA1<\/span><\/a> comme l\u2019\u00e9tude a pu le montrer, soul\u00e8ve d\u2019int\u00e9ressantes questions pour l\u2019avenir. Par exemple, celle du type d\u2019interneurones de la r\u00e9gion\u00a0CA1 impliqu\u00e9s dans la g\u00e9n\u00e9ration des rythmes, ou comment se fait l\u2019int\u00e9gration des autres rythmes observ\u00e9s dans le cortex, comme le <a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/i\/i_12\/i_12_cl\/i_12_cl_con\/i_12_cl_con.html\"><span style=\"color: #008080;\">rythme Gamma<\/span><\/a>.<\/p>\n<p><span style=\"color: #008080;\"><img loading=\"lazy\" style=\"border: 0pt;\" src=\"https:\/\/www.blog-lecerveau.org\/wp-content\/uploads\/i_lien.gif\" alt=\"i_lien\" width=\"15\" height=\"15\" \/> <\/span><a href=\"http:\/\/douglas.qc.ca\/news\/673\" target=\"_blank\" rel=\"noopener\"><span style=\"color: #008080;\">Une \u00e9quipe de chercheurs du Douglas red\u00e9finit le r\u00f4le d&rsquo;une r\u00e9gion du cerveau active dans l&rsquo;organisation de la m\u00e9moire<\/span><\/a><br \/>\n<a href=\"http:\/\/lecerveau.mcgill.ca\/flash\/capsules\/articles_pdf\/williams_nv.pdf\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" style=\"border: 0pt;\" src=\"https:\/\/www.blog-lecerveau.org\/wp-content\/uploads\/a_exp.gif\" alt=\"a_exp\" width=\"15\" height=\"15\" \/> <span style=\"color: #ff0000;\">Hippocampal theta rhythms follow the beat of their own drum + Self-generated theta oscillations in the hippocampus<\/span><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Il arrive parfois que des d\u00e9couvertes scientifiques importantes ne soient pas tant le fruit d\u2019une exp\u00e9rience particuli\u00e8re, mais du long travail pr\u00e9alable pour mettre au point le protocole exp\u00e9rimental. C\u2019est le cas d\u2019une \u00e9tude de Sylvain Williams publi\u00e9e en novembre 2009 dans Nature Neuroscience. Pendant des ann\u00e9es, Williams et ses collaborateurs ont raffin\u00e9 une technique [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[67,21,22,68,69],"_links":{"self":[{"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/posts\/18"}],"collection":[{"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/comments?post=18"}],"version-history":[{"count":4,"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/posts\/18\/revisions"}],"predecessor-version":[{"id":2546,"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/posts\/18\/revisions\/2546"}],"wp:attachment":[{"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/media?parent=18"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/categories?post=18"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.blog-lecerveau.org\/debutant\/wp-json\/wp\/v2\/tags?post=18"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}