{"_buckets": {"deposit": "6355047a-679f-4a00-89a1-4c738c93754b"}, "_deposit": {"created_by": 21, "id": "1689", "owners": [21], "pid": {"revision_id": 0, "type": "depid", "value": "1689"}, "status": "published"}, "_oai": {"id": "oai:ir.soken.ac.jp:00001689", "sets": ["20"]}, "author_link": ["0", "0", "0"], "item_1_biblio_info_21": {"attribute_name": "書誌情報（ソート用）", "attribute_value_mlt": [{"bibliographicIssueDates": {"bibliographicIssueDate": "2010-03-24", "bibliographicIssueDateType": "Issued"}, "bibliographic_titles": [{}]}]}, "item_1_creator_2": {"attribute_name": "著者名", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "鈴木, 郁夫"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_creator_3": {"attribute_name": "フリガナ", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "スズキ, イクオ"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_date_granted_11": {"attribute_name": "学位授与年月日", "attribute_value_mlt": [{"subitem_dategranted": "2010-03-24"}]}, "item_1_degree_grantor_5": {"attribute_name": "学位授与機関", "attribute_value_mlt": [{"subitem_degreegrantor": [{"subitem_degreegrantor_name": "総合研究大学院大学"}]}]}, "item_1_degree_name_6": {"attribute_name": "学位名", "attribute_value_mlt": [{"subitem_degreename": "博士（理学）"}]}, "item_1_description_1": {"attribute_name": "ID", "attribute_value_mlt": [{"subitem_description": "2010039", "subitem_description_type": "Other"}]}, "item_1_description_12": {"attribute_name": "要旨", "attribute_value_mlt": [{"subitem_description": "A remarkable feature of the mammalian evolution is the expansion of the\u003cbr /\u003eneocortex and emergence of the specific internal cytoarchitecture, the layer\u003cbr /\u003estructure. All of the mammalian species share the neocortical layer structure, in\u003cbr /\u003ewhich a similar type of neurons are arranged in a particular layer parallel to the\u003cbr /\u003ebrain surface. During the neocortical de-velopment, the neuronal subtypes in the\u003cbr /\u003eneocortical layers are produced from neural progenitor cells in a stereotyped\u003cbr /\u003etemporal sequence from deep to upper layers. This stereotyped sequence of\u003cbr /\u003eneuronal production is attributed to the temporal restriction of the competence\u003cbr /\u003eof neural progenitors. The progenitors initially possess the multipotency to\u003cbr /\u003egenerate the neuronal subtypes in all neocortical layers, but gradually loose the\u003cbr /\u003epotency during the development, and eventually become only able to produce the\u003cbr /\u003eupper layer neurons.\u003cbr /\u003e　　The dorsal region of the telencephalon called the pallium is the\u003cbr /\u003enon-mamalian homologue of the neocortex, because the same developmentally\u003cbr /\u003eimportant genes are commonly expressed in the mammalian neocortex and the\u003cbr /\u003enon-mammalian pallium. Although the pallium is completely conserved among\u003cbr /\u003ethe vertebrates, the internal structure is variable. For example, the bird, one of\u003cbr /\u003ethe closest relatives of the mammals, possesses the well-developed pallium\u003cbr /\u003epacked with distinct subtypes of neurons that are arranged in particular\u003cbr /\u003edomains. Such observations suggest that the common ancestor of the mammals\u003cbr /\u003eand the birds had already acquired the pallium, and that the pallial structure\u003cbr /\u003ehas been modified in an animal group-specific manner through alterations in the\u003cbr /\u003edevelopmental processes. Therefore, a key event contributing to the evolutionary\u003cbr /\u003eemergence of the neocortical layer structure could be found through comparison\u003cbr /\u003eof the development between the mammalian neocortex and the non-mammalian\u003cbr /\u003epallium.\u003cbr /\u003e　　The chick pallium is a good model to approach the problem, because of the\u003cbr /\u003eclosest phylogenetic position to the mammals as well as the convenience of\u003cbr /\u003eexperimental manipulations. For over a century, it has been argued whether the\u003cbr /\u003eavian pallium has a comparable neuronal repertory to the mammalian neocortex.\u003cbr /\u003eTherefore, I first checked expression patterns of marker genes for the\u003cbr /\u003emammalian neocortical layers in the chick pallium. This analysis revealed that\u003cbr /\u003eboth the deep (layer V) and upper layer (layer II/III) marker genes were\u003cbr /\u003eexpressed in the chick pallium, suggesting that the chick pallium possesses a\u003cbr /\u003eneuronal repertory similar to the mammalian neocortex. In addition to the\u003cbr /\u003emolecular expressions, the axon projections were also found to be partially\u003cbr /\u003esimilar between the chick pallial neurons and the corresponding neuronal\u003cbr /\u003esubtypes of the mammalian neocortex. In spite of the remarkable conservation\u003cbr /\u003ein the neuronal repertory, spatial distribution patterns of the deep and upper\u003cbr /\u003elayer neurons were entirely different from the layer arrangement of the\u003cbr /\u003emammalian neocortex; in the chick pallium, the deep and upper layer neurons\u003cbr /\u003ewere not arranged in parallel, but distantly located in the medial and lateral\u003cbr /\u003eside, respectively.\u003cbr /\u003e　 The development of the deep and upper layer neurons in the chick pallium\u003cbr /\u003ewas investigated in detail. First, the birthdate analysis by BrdU pulse-labeling\u003cbr /\u003edemonstrated that the deep layer neurons were generated earlier than the\u003cbr /\u003eupper layer neurons in the chick pallium, suggesting that the temporal sequence\u003cbr /\u003eof the neuron production is evolutionarily conserved between the mammals and\u003cbr /\u003ethe birds. Second, the fate mapping analysis revealed that the deep and upper\u003cbr /\u003elayer neurons originated from the distinct neural progenitors on the medial and\u003cbr /\u003elateral sides in the chick pallium, respectively. This spatially separate\u003cbr /\u003eproduction of the neurons is the critical difference from the mammalian\u003cbr /\u003eneocortical development, in which the deep and upper layer neurons are\u003cbr /\u003euniformly produced across the entire neocortex. Probably related to this\u003cbr /\u003edifference, I found that the late neurogenesis in the chick pallium\u003cbr /\u003epredominantly occurs on the lateral side. This spatiotemporally biased neuronal\u003cbr /\u003eproduction can explain the selective generation of the late-born upper layer\u003cbr /\u003eneurons only from the lateral side in the chick pallium. Taken together, the\u003cbr /\u003edistinct neurogenetic properties between the medial and lateral progenitors\u003cbr /\u003eappeared to be the key to construct the non-layered domain-like cytoarchiteture\u003cbr /\u003ein the chick pallium.\u003cbr /\u003e　 How then is the medio-lateral difference of neurogenetic properties is\u003cbr /\u003einstructed in the chick pallium? I cultured neural progenitor cells from the\u003cbr /\u003emedial and lateral sides of the chick pallium in a clonal density, and\u003cbr /\u003esurprisingly found that most of the clones derived from a single progenitor cell\u003cbr /\u003econtained both deep and upper layer neurons, regardless of its origin. This\u003cbr /\u003eremarkable observation clearly demonstrated that the neural progenitor cells in\u003cbr /\u003ethe medial and lateral sides of the chick pallium intrinsically possess a similar\u003cbr /\u003eneurogenic competence, and the neurocompetency is extrinsically regulated by\u003cbr /\u003ethe surrounding tissues according to the spatial positions.\u003cbr /\u003e　 On the basis on the results obtained, I propose the following model for the\u003cbr /\u003eavian pallial development. The avian neural progenitors are intrinsically\u003cbr /\u003eequivalent to those of mammals and capable of sequentially generating a full\u003cbr /\u003erepertory of neuronal subtypes. However, the neurogenesis in the avian pallium\u003cbr /\u003eis extrinsically regulated by two potential mechanisms. First, the deep layer fate\u003cbr /\u003ein the early-born neurons on the lateral side is suppressed by environmental\u003cbr /\u003efactors, and thereby, the lateral neural progenitor cells produce only the upper\u003cbr /\u003elayer neurons in the later phase of neurogenesis. Second, the medial neural\u003cbr /\u003eprogenitors terminate the neurogenesis precociously before producing the upper\u003cbr /\u003elayer neurons leading to the preferential generation of deep layer neurons from\u003cbr /\u003ethe medial side.\u003cbr /\u003e　　Lastly, the emergence of the layered neocortex in mammals has been a\u003cbr /\u003elong-standing mystery in evolutionary biology. The present discovery of the\u003cbr /\u003eevolutionary conservation in the neural progenitor competence between the\u003cbr /\u003emammals and the avian suggests that the common ancestor of the amniotes has\u003cbr /\u003ealready possessed the developmental potential to sequentially produce the\u003cbr /\u003emultiple neuronal subtypes. During the evolutionary diversification into each\u003cbr /\u003elineage of animal groups, alterations in the spatial regulation of the\u003cbr /\u003eneurogenetic program may have contributed to the emergence of animal\u003cbr /\u003egroup-specific brain structures, such as the layer structure in the mammalian\u003cbr /\u003eneocortex and the domain structure in the avian pallium.", "subitem_description_type": "Other"}]}, "item_1_description_18": {"attribute_name": "フォーマット", "attribute_value_mlt": [{"subitem_description": "application/pdf", "subitem_description_type": "Other"}]}, "item_1_description_7": {"attribute_name": "学位記番号", "attribute_value_mlt": [{"subitem_description": "総研大甲第1343号", "subitem_description_type": "Other"}]}, "item_1_select_14": {"attribute_name": "所蔵", "attribute_value_mlt": [{"subitem_select_item": "有"}]}, "item_1_select_16": {"attribute_name": "複写", "attribute_value_mlt": [{"subitem_select_item": "印刷物から複写可"}]}, "item_1_select_17": {"attribute_name": "公開状況", "attribute_value_mlt": [{"subitem_select_item": "全文公開可"}]}, "item_1_select_8": {"attribute_name": "研究科", "attribute_value_mlt": [{"subitem_select_item": "生命科学研究科"}]}, "item_1_select_9": {"attribute_name": "専攻", "attribute_value_mlt": [{"subitem_select_item": "18 遺伝学専攻"}]}, "item_1_text_10": {"attribute_name": "学位授与年度", "attribute_value_mlt": [{"subitem_text_value": "2009"}]}, "item_creator": {"attribute_name": "著者", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "SUZUKI, Ikuko", "creatorNameLang": "en"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_files": {"attribute_name": "ファイル情報", "attribute_type": "file", "attribute_value_mlt": [{"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 0, "filename": "甲1343_要旨.pdf", "filesize": [{"value": "359.8 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 359800.0, "url": {"label": "要旨・審査要旨", "url": "https://ir.soken.ac.jp/record/1689/files/甲1343_要旨.pdf"}, "version_id": "d49bba6f-5571-4a3e-9d25-d17cf033642a"}, {"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 1, "filename": "甲1343_本文_①.pdf", "filesize": [{"value": "461.5 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 461500.0, "url": {"label": "本文_①", "url": "https://ir.soken.ac.jp/record/1689/files/甲1343_本文_①.pdf"}, "version_id": "ffc2dfaf-a3bf-4eb6-b042-bcb3d21c7fb9"}, {"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 2, "filename": "甲1343_本文_②.pdf", "filesize": [{"value": "294.7 MB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 294700000.0, "url": {"label": "本文_②", "url": "https://ir.soken.ac.jp/record/1689/files/甲1343_本文_②.pdf"}, "version_id": "0a10029c-f427-4f9e-8913-14185faa9bea"}]}, "item_language": {"attribute_name": "言語", "attribute_value_mlt": [{"subitem_language": "eng"}]}, "item_resource_type": {"attribute_name": "資源タイプ", "attribute_value_mlt": [{"resourcetype": "thesis", "resourceuri": "http://purl.org/coar/resource_type/c_46ec"}]}, "item_title": "Conservation of developmental mechanisms in evolutionarily divergent brain structures", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "Conservation of developmental mechanisms in evolutionarily divergent brain structures"}, {"subitem_title": "Conservation of developmental mechanisms in evolutionarily divergent brain structures", "subitem_title_language": "en"}]}, "item_type_id": "1", "owner": "21", "path": ["20"], "permalink_uri": "https://ir.soken.ac.jp/records/1689", "pubdate": {"attribute_name": "公開日", "attribute_value": "2011-01-19"}, "publish_date": "2011-01-19", "publish_status": "0", "recid": "1689", "relation": {}, "relation_version_is_last": true, "title": ["Conservation of developmental mechanisms in evolutionarily divergent brain structures"], "weko_shared_id": -1}