{"created":"2023-06-26T11:01:47.610411+00:00","id":2549,"links":{},"metadata":{"_buckets":{"deposit":"91d64587-fa8b-4291-95a6-21c7b444c5f6"},"_deposit":{"created_by":22,"id":"2549","owners":[22],"pid":{"revision_id":0,"type":"depid","value":"2549"},"status":"published"},"_oai":{"id":"oai:oist.repo.nii.ac.jp:00002549","sets":["7:235"]},"author_link":[],"item_10006_creator_3":{"attribute_name":"Author","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Taira, Masakazu","creatorNameLang":"en"}]}]},"item_10006_date_granted_11":{"attribute_name":"Degree Conferral Date","attribute_value_mlt":[{"subitem_dategranted":"2022-01-31"}]},"item_10006_degree_grantor_9":{"attribute_name":"Degree Conferrral Institution","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"Okinawa Institute of Science and Technology Graduate University"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"38005","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_10006_degree_name_8":{"attribute_name":"Degree","attribute_value_mlt":[{"subitem_degreename":"Doctor of Philosophy"}]},"item_10006_description_7":{"attribute_name":"Abstract","attribute_value_mlt":[{"subitem_description":"Serotonin (5-HT) is an important neuromodulator in reward-driven learning and decision making. The dorsal raphe nucleus (DRN) sends diffuse 5-HT projections throughout the brain. The involvement of DRN 5-HT neurons in reward-based behaviors has been examined using various types of behavioral tasks; however, how DRN 5-HT affects computational processes of decision making remains unclear. Reinforcement learning (RL) is a theoretical framework to describe the decision making process. Previous studies based on the RL framework have proposed hypotheses on the role of 5-HT in decision making, such as temporal discounting and model-based value computation. The overall aim of this thesis is to examine these hypotheses by analyzing behaviors under optogenetic manipulation, thereby clarifying the role of DRN 5-HT neurons in reward-based behaviors. The first hypothesis is that 5-HT modulates the relative importance of future rewards. Previous behavioral studies showed that 5-HT activation enhances patience to wait for future rewards and vice versa. However, how 5-HT regulates persistence to act for future rewards remains unknown. In the first part of my thesis research, I trained mice to perform a free-operant lever-pressing task, in which motor action rather than stationary waiting was required to obtain delayed rewards. In testing the effects of optogenetic activation and inhibition of 5-HT neurons on sustained motor actions, I found that optogenetic activation or inhibition of 5-HT neurons did not affect persistence in motor actions but an effect of the activation on slowing down response vigor, suggesting a different role of 5-HT neurons in motor actions for future rewards compared to stationary waiting. The second hypothesis examined is that 5- HT affects model-based decision making. In model-based decision making, agents use their own internal models of action-outcome relationships to plan forward and to select actions. Previous computational studies proposed facilitation of model-based decision making by 5-HT neurons, but behavioral evidence of how 5-HT regulates the process is still limited. A two-step decision making task is an established behavioral task to understand model-based decision making. In the second half of my thesis project, I trained mice to perform the two-step decision making task and found that optogenetic inhibition of 5-HT neurons affected choice behaviors and reduced time to make decisions possibly reflecting the disruption of model-based decision making. By fitting behavioral data to a model-free/model-based hybrid model, I found that photoinhibition of 5-HT neurons decreased the weight of model-based decision making. These results revealed the role of 5-HT neurons reward-based behaviors and model-based computations.","subitem_description_type":"Other"}]},"item_10006_dissertation_number_12":{"attribute_name":"Degree Referral Number","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第86号"}]},"item_10006_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15102/1394.00002295","subitem_identifier_reg_type":"JaLC"}]},"item_10006_rights_13":{"attribute_name":"Copyright Information","attribute_value_mlt":[{"subitem_rights":"© 2022 The Author."}]},"item_10006_text_24":{"attribute_name":"Exam Date","attribute_value_mlt":[{"subitem_text_value":"2021-12-08"}]},"item_10006_version_type_18":{"attribute_name":"Version Format","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2022-02-09"}],"displaytype":"detail","filename":"Taira_FullText.pdf","filesize":[{"value":"5.0 MB"}],"format":"application/pdf","licensefree":"CC BY 4.0\nAttribution 4.0 International\nhttps://creativecommons.org/licenses/by/4.0/","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"Taira_FullText","objectType":"fulltext","url":"https://oist.repo.nii.ac.jp/record/2549/files/Taira_FullText.pdf"},"version_id":"a5ca8a2c-b62e-4043-a863-69ba856fddbe"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2022-02-09"}],"displaytype":"detail","filename":"Taira_FinalExamAbstract.pdf","filesize":[{"value":"42.9 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"Taira_FinalExamAbstract","objectType":"abstract","url":"https://oist.repo.nii.ac.jp/record/2549/files/Taira_FinalExamAbstract.pdf"},"version_id":"9b0895dc-1ea0-4b6c-a3e6-0405604d0d1d"}]},"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":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"報酬に基づく行動におけるセロトニンの制御に関する研究","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"報酬に基づく行動におけるセロトニンの制御に関する研究","subitem_title_language":"ja"},{"subitem_title":"The Role of Serotonin Neurons in Mouse Reward-based Behaviors","subitem_title_language":"en"}]},"item_type_id":"10006","owner":"22","path":["235"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2022-02-09"},"publish_date":"2022-02-09","publish_status":"0","recid":"2549","relation_version_is_last":true,"title":["報酬に基づく行動におけるセロトニンの制御に関する研究"],"weko_creator_id":"22","weko_shared_id":-1},"updated":"2023-09-01T02:32:38.711827+00:00"}