Zbyte\u010dn\u00e9 informace, kter\u00e9 se b\u011bhem dne nahromadily v pam\u011bti, zmiz\u00ed, aby daly prostor nov\u00fdm zku\u0161enostem a optimalizovaly energetickou spot\u0159ebu mozku. Ten si „zd\u0159\u00edmne“ i v bd\u011bl\u00e9m stavu. V\u011bdci to poprv\u00e9 pozorovali u my\u0161\u00ed, u nich\u017e se v\u011bt\u0161\u00ed \u010d\u00e1st spojen\u00ed mezi neurony b\u011bhem sp\u00e1nku zmen\u0161uje v pr\u016fm\u011bru o 20 procent.<\/p>\n
Objev publikovali na str\u00e1nk\u00e1ch \u010dasopisu Science ital\u0161t\u00ed v\u011bdci Luisa De Vivov\u00e1, Chiara Cirelliov\u00e1 a Giulio Tononi p\u016fsob\u00edc\u00ed na Wisconsinsk\u00e9 univerzit\u011b, a Michele Bellesi z Polytechnick\u00e9 univerzity ve st\u0159edoitalsk\u00e9 Ancon\u011b.<\/p>\n
Studie ukon\u010dila letitou diskusi o \u00faloze sp\u00e1nku v procesu u\u010den\u00ed a potvrdila teorii, kterou Cirelliov\u00e1 a Tononi vypracovali p\u0159ed n\u011bkolika lety. „Podle jejich hypot\u00e9zy ur\u010duje vz\u00e1jemn\u00e9 p\u016fsoben\u00ed s okol\u00edm v dob\u011b bd\u011blosti postupn\u00e9 posilov\u00e1n\u00ed synaps\u00ed, proto\u017ee se neust\u00e1le u\u010d\u00edme nov\u00e9 v\u011bci, i kdy\u017e si to neuv\u011bdomujeme. Sp\u00e1nek naopak slou\u017e\u00ed k tomu, aby se synapse vr\u00e1tily na energeticky udr\u017eiteln\u011bj\u0161\u00ed \u00farove\u0148 a dovolily n\u00e1m u\u010dit se dal\u0161\u00ed den nov\u00e9 v\u011bci. D\u00edky t\u00e9to studii se n\u00e1m poprv\u00e9 poda\u0159ilo z\u00edskat vizu\u00e1ln\u00ed d\u016fkaz tohoto jevu,“ citoval Bellesiho italsk\u00fd den\u00edk La Repubblica.<\/p>\n
C\u00edlem sp\u00e1nku je tedy zapomenout zbyte\u010dn\u00e9 vzpom\u00ednky. V\u011bdci s pou\u017eit\u00edm sofistikovan\u00e9ho elektronick\u00e9ho 3D mikroskopu m\u011b\u0159ili a rekonstruovali t\u00e9m\u011b\u0159 7000 synaps\u00ed odebran\u00fdch z motorick\u00e9 a senzorick\u00e9 oblasti mozkov\u00e9 k\u016fry p\u0159ed odpo\u010dinkem a po n\u011bm. Vytvo\u0159ili tak nejv\u011bt\u0161\u00ed datab\u00e1zi synaps\u00ed na sv\u011bt\u011b, p\u0159ipom\u00edn\u00e1 Bellesi. Po \u010dty\u0159ech letech n\u00e1ro\u010dn\u00e9 pr\u00e1ce v\u011bdci zjistili, \u017ee se osm synaps\u00ed z deseti (p\u0159edev\u0161\u00edm ty mal\u00e9 a st\u0159edn\u00ed) zmen\u0161uje \u00fam\u011brn\u011b ke sv\u00e9 velikosti, zat\u00edmco ty v\u011bt\u0161\u00ed, kter\u00e9 uchov\u00e1vaj\u00ed d\u016fle\u017eit\u011bj\u0161\u00ed informace, z\u016fst\u00e1vaj\u00ed stabiln\u00ed.<\/p>\n
Mozkov\u00e9 bu\u0148ky p\u0159ech\u00e1zej\u00ed z jak\u00e9hosi stavu „on“, kdy se aktivuj\u00ed, do stavu „off“, kter\u00fd je z\u0159ejm\u011b ur\u010den k tomu, aby mozek \u0161et\u0159il energi\u00ed. To ovliv\u0148uje i na\u0161i \u00farove\u0148 pozornosti a vyvol\u00e1v\u00e1 epizody nev\u011bdom\u00e9 nepozornosti, kdy jsme jaksi „odpojeni“. Uk\u00e1zala to studie Stanfordovy univerzity ve Spojen\u00fdch st\u00e1tech.<\/p>\n
V\u011bdci objevili tento jev na my\u0161\u00edch. Registrovali aktivitu koloni\u00ed neuron\u016f, kter\u00e9 tvo\u0159\u00ed r\u016fzn\u00e9 vrstvy mozkov\u00e9 k\u016fry. „V aktivn\u00edm stavu za\u010d\u00ednaj\u00ed v\u0161echny neurony velmi rychle vys\u00edlat sign\u00e1ly, pak n\u00e1hle svou aktivitu zastav\u00ed,“ vysv\u011btluje docent bioin\u017een\u00fdrstv\u00ed na Stanfordov\u011b univerzit\u011b Kwabena Boahen. Toto „on“ a „off“ se odehr\u00e1v\u00e1 kontinu\u00e1ln\u011b.<\/p>\n
Kdy\u017e mus\u00edme v\u011bnovat pozornost n\u011bjak\u00e9mu stimulu poch\u00e1zej\u00edc\u00edmu z vn\u011bj\u0161\u00edho sv\u011bta, odpov\u00eddaj\u00edc\u00ed neurony v mozku spole\u010dn\u011b osciluj\u00ed mezi „on“ a „off“. V\u00edce \u010dasu jsou ale v aktivovan\u00e9mu stavu, a umo\u017e\u0148uj\u00ed tak rychlej\u0161\u00ed reakci. Pro\u010d neurony st\u0159\u00eddav\u011b odpo\u010d\u00edvaj\u00ed i b\u011bhem bd\u011bn\u00ed, nen\u00ed dosud jasn\u00e9, v\u011bdci ale p\u0159edpokl\u00e1daj\u00ed, \u017ee jde o mechanismus energetick\u00fdch \u00faspor. Kdy\u017e jsou neurony aktivn\u00ed a vys\u00edlaj\u00ed sign\u00e1ly s vysokou frekvenc\u00ed, produkuj\u00ed odpad nebezpe\u010dn\u00fd pro tyto bu\u0148ky. Periody zpomalen\u00ed sign\u00e1l\u016f tedy mohou slou\u017eit k jak\u00e9si o\u010dist\u011b od toxick\u00e9ho odpadu.<\/p>\n
Na z\u00e1klad\u011b t\u011bchto v\u00fdsledk\u016f nyn\u00ed v\u011bdci cht\u011bj\u00ed zkoumat \u00fa\u010dinky vyvolan\u00e9 nedostatkem sp\u00e1nku a zm\u011bnami rytmu sp\u00e1nku a bd\u011bn\u00ed typick\u00e9 pro modern\u00ed \u017eivot.<\/p>\n","protected":false},"excerpt":{"rendered":"
Zbyte\u010dn\u00e9 informace, kter\u00e9 se b\u011bhem dne nahromadily v pam\u011bti, zmiz\u00ed, aby daly prostor nov\u00fdm zku\u0161enostem a optimalizovaly energetickou spot\u0159ebu mozku. Ten si „zd\u0159\u00edmne“ i v […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":15254,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-27580","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-zpravy"],"_links":{"self":[{"href":"https:\/\/www.invarena.cz\/index.php?rest_route=\/wp\/v2\/posts\/27580","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.invarena.cz\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.invarena.cz\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.invarena.cz\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.invarena.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=27580"}],"version-history":[{"count":0,"href":"https:\/\/www.invarena.cz\/index.php?rest_route=\/wp\/v2\/posts\/27580\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.invarena.cz\/index.php?rest_route=\/wp\/v2\/media\/15254"}],"wp:attachment":[{"href":"https:\/\/www.invarena.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=27580"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.invarena.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=27580"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.invarena.cz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=27580"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}