{"id":3006,"date":"2010-12-23T05:40:36","date_gmt":"2010-12-23T03:40:36","guid":{"rendered":"http:\/\/localhost\/azgad\/wordpress\/?p=3006"},"modified":"2010-12-23T05:52:00","modified_gmt":"2010-12-23T03:52:00","slug":"fozen-in-fear-fear-responses-of-zebrafish-are-controlled-by-brain-structures-of-previously-unknown-function","status":"publish","type":"post","link":"https:\/\/azgad.com\/?p=3006","title":{"rendered":"Fozen in fear – fear responses of zebrafish are controlled by brain structures of previously unknown function"},"content":{"rendered":"

.
\nA brain structure called the habenula is crucial for modifications of fear responses in zebrafish, according
\nto a new study by researchers from the RIKEN Brain Science Institute. The zebrafish dorsal habenula is
\nsubdivided into two regions, each connected to different brain structures, but the function of each, and the
\nsignificance of their connections, was unclear.
\n.
\n.
\n\"\"<\/a>
\n.
\nFigure 1<\/strong>: Confocal fluorescence micrograph of the larval zebrafish brain, showing neural pathways from
\nthe lateral (red) and medial (green) subnuclei of the dorsal habenula to the interpeduncular nucleus<\/em>
\n.
\n.
\nHitoshi Okamoto and his colleagues used fluorescent dyes to trace the neural pathways from the interpeduncular
\nnucleus (IPN), which receives connections from the dorsal habenula region (Fig. 1). They found that the dorsal
\nIPN projects to midbrain structures called the dorsal raphe nucleus and griseum centrale. The corresponding
\n structures in the mammalian brain have been implicated in responses to fear and stress, suggesting that the
\n habenula\u2013IPN pathway in zebrafish is also involved in these responses.
\n.
\nTo investigate this, the researchers created transgenic zebrafish expressing tetanus toxin in the lateral subnucleus
\nof the dorsal habenula. The toxin blocks neurotransmission, preventing neurons in that region from sending signals.
\n.
\nThe transgenic fish were then subjected to an established fear conditioning task, in which a red light is repeatedly
\npaired with an electric shock. Normally, the fish learn to associate the two stimuli, and become agitated\u2014recognized
\nby an increase in the frequency of turning\u2014in the presence of the light alone. However, when the transgenic fish
\n encountered the red light after the fear conditioning task, they froze rather than escaping. Okamoto and colleagues
\nobserved these differences between the transgenic fish and controls during the fear conditioning task. Both froze the
\n first time they encountered the red light; the controls started to become agitated the second time, but the transgenic
\nfish continued to freeze.
\n.
\nThe exploratory behavior of the transgenic fish was no different from that of the controls, showing that their responses to
\nfear conditioning were not due to abnormal sensory or motor function. Instead, the results suggest to the researchers that
\n the transgenic fish cannot modify their fear response after new experiences. They therefore conclude that experience-
\ndependent modifications of fear responses are controlled by the neurons in the lateral subnucleus of the dorsal habenula
\n in the zebrafish.
\n.
\n\u201cWe would like to know whether the same regulation mechanism works in mammals, including humans,\u201d
\nsays Okamoto, \u201cand would also like to extend our research to reveal the functions of the other parts of
\nthe habenula.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

. A brain structure called the habenula is crucial for modifications of fear responses in zebrafish, according to a new study by researchers from the RIKEN Brain Science Institute. The zebrafish dorsal habenula is subdivided into two regions, each connected to different brain structures, but the function of each, and the significance of their connections, … <\/p>\n

\u05d4\u05de\u05e9\u05d9\u05db\u05d5 \u05d1\u05e7\u05e8\u05d9\u05d0\u05d4<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[10],"tags":[273,513,186],"class_list":["post-3006","post","type-post","status-publish","format-standard","hentry","category-10","tag-273","tag-513","tag-186","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3006","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3006"}],"version-history":[{"count":7,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3006\/revisions"}],"predecessor-version":[{"id":3014,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3006\/revisions\/3014"}],"wp:attachment":[{"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3006"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3006"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3006"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}