{"id":25008,"date":"2014-06-01T13:41:29","date_gmt":"2014-06-01T10:41:29","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=25008"},"modified":"2018-05-10T13:48:35","modified_gmt":"2018-05-10T10:48:35","slug":"yeni-beyin-hucreleri-eski-anilari-siliyor","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2014\/06\/01\/yeni-beyin-hucreleri-eski-anilari-siliyor","title":{"rendered":"Yeni beyin h\u00fccreleri eski an\u0131lar\u0131 siliyor!"},"content":{"rendered":"<p><em>Science<\/em> dergisinde yay\u0131mlanan ara\u015ft\u0131rma sonucuna g\u00f6re, beynin an\u0131 kayd\u0131ndan sorumlu olan b\u00f6lgesi olan hipokamp\u00fcs i\u00e7indeki yeni n\u00f6ronlar, \u00f6nceki bilgileri unutturabiliyor. Bu bulgu, \u00e7ocukluk d\u00f6nemi an\u0131lar\u0131m\u0131z\u0131n hat\u0131rlanmas\u0131nda neden zorluk ya\u015fad\u0131\u011f\u0131m\u0131z\u0131 a\u00e7\u0131klayacak ipu\u00e7lar\u0131 ta\u015f\u0131yor olabilir.<\/p>\n<p>Kanada Toronto Hasta \u00c7ocuklar Hastanesi\u2019nden konuyla ilgili ara\u015ft\u0131rmay\u0131 yapan sinirbilimci Sheena Josselyn ve birlikte \u00e7al\u0131\u015ft\u0131\u011f\u0131 e\u015fi Paul Frankland, bulgular\u0131n ba\u015flang\u0131\u00e7ta kendilerini \u00e7ok \u015fa\u015f\u0131rtt\u0131\u011f\u0131n\u0131 s\u00f6yl\u00fcyorlar. \u00c7\u00fcnk\u00fc bug\u00fcne dek, hemen herkesin ortak fikri, yeni n\u00f6ronlar\u0131n haf\u0131zay\u0131 kuvvetlendirece\u011fi y\u00f6n\u00fcndeydi.<\/p>\n<p>\u0130nsanlar, fareler ve daha bir\u00e7ok memelinin hayat\u0131 boyunca hipokamp\u00fcs b\u00f6lgesinde yeni n\u00f6ronlar olu\u015fur. Ba\u015flang\u0131\u00e7ta h\u0131zl\u0131 olan bu yenilenme, ya\u015f ilerledik\u00e7e yava\u015flar. Daha \u00f6nce eri\u015fkin fareler \u00fczerinde yap\u0131lan \u00e7al\u0131\u015fmalar, \u00f6\u011frenme \u00f6ncesi n\u00f6ral \u00e7o\u011falma art\u0131\u015f\u0131n\u0131n haf\u0131zay\u0131 da olumlu etkiledi\u011fini g\u00f6stermi\u015fti. Ancak bu son \u00e7al\u0131\u015fma, bilgi \u00f6\u011frenildikten sonra olu\u015fan n\u00f6ron art\u0131\u015f\u0131n\u0131n, buna ba\u011fl\u0131 haf\u0131zay\u0131 olumsuz etkiledi\u011fini g\u00f6sterdi.<\/p>\n<p>Josselyn\u2019e g\u00f6re n\u00f6ronlar\u0131n bu y\u0131k\u0131c\u0131 tavr\u0131 mant\u0131ks\u0131z gibi g\u00f6r\u00fcnse de, bir anlam ifade ediyor. Haf\u0131zan\u0131n \u00e7embersel bir yap\u0131s\u0131 oldu\u011funa da vurgu yapan Josselyn, bu \u00e7embersel harekete bir \u015fey eklendi\u011finde, bir \u015feylerin y\u0131k\u0131ma u\u011frayaca\u011f\u0131n\u0131 belirtiyor. Josselyn, yeni eklenen n\u00f6ronlar\u0131n eski an\u0131lar\u0131 temizleyip yerine yenilerinin konulmas\u0131nda yararl\u0131 bir rol oynayaca\u011f\u0131n\u0131 d\u00fc\u015f\u00fcn\u00fcyor.<\/p>\n<p>Ara\u015ft\u0131rmac\u0131lar yeni do\u011fmu\u015f ve eri\u015fkin fareler \u00fczerinde, ko\u015fullanm\u0131\u015f g\u00f6rev deneyi yapt\u0131 ve farelerin elektrik \u015fokundan ka\u00e7ma davran\u0131\u015f\u0131 edinmelerini g\u00f6zlemlediler. \u0130lgin\u00e7 bir \u015fekilde yeni do\u011fmu\u015f fareler bu negatif deneyimi sadece 1 g\u00fcn haf\u0131zalar\u0131nda tutabilirken, eri\u015fkinler haftalarca ka\u00e7\u0131nma davran\u0131\u015f\u0131 g\u00f6sterebilmi\u015flerdi. Bu farkl\u0131l\u0131k, n\u00f6ron \u00e7o\u011falmas\u0131ndaki (proliferasyon) farkl\u0131l\u0131kla ba\u011flant\u0131l\u0131 gibi g\u00f6r\u00fcn\u00fcyor. Josselyn ve arkada\u015flar\u0131, yeni do\u011fmu\u015f farelerde yeni n\u00f6ron geli\u015fimini genetik ve kimyasal olarak bask\u0131layarak, \u00f6\u011frenmeden sonraki haf\u0131zay\u0131 g\u00fc\u00e7lendirebildiler. Eri\u015fkin farelerdeyse n\u00f6ron \u00e7o\u011falmas\u0131n\u0131 artt\u0131rd\u0131\u011f\u0131 bilinen 4-6 haftal\u0131k d\u00fczenli egzersizden sonra, \u00f6\u011frenilmi\u015f ka\u00e7ma davran\u0131\u015f\u0131n\u0131n s\u00fcreklili\u011finin azald\u0131\u011f\u0131 izlendi.<\/p>\n<p>\u0130nsanlarda, genetik ve kimyasal manip\u00fclasyon uygulanamayaca\u011f\u0131ndan, bu bulgular\u0131n izinin s\u00fcr\u00fclmesi zor. Fakat fare ve insanlarda, infantil amnezi denilen erken ya\u015fam deneyimlerinin unutulmas\u0131n\u0131n ortak oldu\u011fu biliniyor. Pek \u00e7ok gen\u00e7 hayvandaki h\u0131zl\u0131 n\u00f6ron yenilenmesi, t\u00fcrler aras\u0131 ge\u00e7i\u015fi de a\u00e7\u0131klayan bir olgu olabilir.<\/p>\n<p>Ara\u015ft\u0131rmac\u0131lar ayr\u0131ca \u00f6\u011frenilmi\u015f korkuyu do\u011fum periyotlar\u0131 farelerden daha uzun ve bununla ba\u011flant\u0131l\u0131 olarak do\u011fum sonras\u0131 azalm\u0131\u015f beyin geli\u015fimi g\u00f6steren kobay farelerinde ve \u015eili kemirgenlerinde g\u00f6zlemlediler. Bebek \u015eili kemirgenleri ve kobay farelerinde infantil amnezi yoktu. Fakat ara\u015ft\u0131rmac\u0131lar hayvanlarda n\u00f6ron geli\u015fimini art\u0131ran ila\u00e7 veya egzersizlerle benzer bir etkiyi taklit ettirebildiler.<\/p>\n<p>Boston Massachusetts Hastanesi\u2019nden yine bir sinirbilimci olan Amar Sahay\u2019a g\u00f6re, bug\u00fcne kadarki \u00e7al\u0131\u015fmalar genellikle haf\u0131zan\u0131n \u015fekillenmesinden \u00f6nceki d\u00f6neme ait olan n\u00f6rogenesis \u00fczerine odaklan\u0131yordu. Bu \u00e7al\u0131\u015fman\u0131n \u00f6\u011frenmeden sonras\u0131na bakmas\u0131, n\u00f6rogenesisle uzun d\u00f6nemli haf\u0131zan\u0131n ili\u015fkisini belirlemede de fayda sa\u011flayacakt\u0131r.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Science dergisinde yay\u0131mlanan ara\u015ft\u0131rma sonucuna g\u00f6re, beynin an\u0131 kayd\u0131ndan sorumlu olan b\u00f6lgesi olan hipokamp\u00fcs i\u00e7indeki yeni n\u00f6ronlar, \u00f6nceki bilgileri unutturabiliyor. Bu bulgu, \u00e7ocukluk d\u00f6nemi an\u0131lar\u0131m\u0131z\u0131n hat\u0131rlanmas\u0131nda neden zorluk ya\u015fad\u0131\u011f\u0131m\u0131z\u0131 a\u00e7\u0131klayacak ipu\u00e7lar\u0131 ta\u015f\u0131yor olabilir. Kanada Toronto Hasta \u00c7ocuklar Hastanesi\u2019nden konuyla ilgili ara\u015ft\u0131rmay\u0131 yapan sinirbilimci Sheena Josselyn ve birlikte \u00e7al\u0131\u015ft\u0131\u011f\u0131 e\u015fi Paul Frankland, bulgular\u0131n ba\u015flang\u0131\u00e7ta kendilerini \u00e7ok [&hellip;]<\/p>\n","protected":false},"author":42,"featured_media":25013,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[161,19],"tags":[298,2444,1087],"class_list":["post-25008","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-124-sayi","category-bilim-gundemi","tag-hafiza","tag-hipokampus","tag-noron"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/25008","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/42"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=25008"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/25008\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media\/25013"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=25008"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=25008"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=25008"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}