{"created":"2023-06-20T13:21:01.463644+00:00","id":1112,"links":{},"metadata":{"_buckets":{"deposit":"73f02a37-c2b0-4de6-a5be-a260c0948f95"},"_deposit":{"created_by":1,"id":"1112","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"1112"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00001112","sets":["2:430:22"]},"author_link":["9356","9354","9355"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"近藤, 秀樹"}],"nameIdentifiers":[{"nameIdentifier":"9354","nameIdentifierScheme":"WEKO"}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"コンドウ, ヒデキ"}],"nameIdentifiers":[{"nameIdentifier":"9355","nameIdentifierScheme":"WEKO"}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2000-03-24"}]},"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_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"Metacontrast masking is a phenomenon in the visual perception in which two brief visual stimuli, the test and mask stimuli, follow each other in rapid succession, which causes the test stimulus to become less visible or invisible even though the test and mask stimuli do not spatially overlap. In the present study, l investigated the relation between the neuron activities in cortical area V4 in the macaque monkey to the metacontrast masking in order to understand how the activities of V4 neurons correlate with the perception of the visual stimulus. First, I conducted psychophysical experiments of metacontrast masking in human subjects. I found that the visibility of the test stimulus was suppressed when the interval between the onset of the test and mask stimuli (stimulus onset asynchrony; SOA) was within a certain range. Maximum suppression of perception of the test stimulus occurred when the SOA was about + 30 to 50 ms and became gradually weaker with an increase in the SOA. The suppression lasted up to about 100 to 200 ms in the positive SOA. In the negative SOA, there was little inhibition of perception. Secondly, I conducted unit recording experiment in area V4 of macaque monkeys. In this part of the study, l studied the temporal characteristics of suppression in area V4 using a visual stimulus for metacontrast masking. Visual responses of V4 neurons to a brief test stimulus presented within the receptive field were recorded, and the effect of a mask stimulus that did not spatially overlap the test stimulus was examined. Responses to the test stimulus were suppressed by the mask stimulus, which either preceded or followed the test stimulus. To study the temporal characteristics of suppression, the SOA between the test stimulus and the mask stimulus was varied. Maximum suppression occurred with a simultaneous presentation of the two stimuli, and the suppression gradually weakened as the SOA increased. The suppressive effect of the mask stimulus lasted on average about 77 ms in the negative SOA (forward masking) and 65 ms in the positive SOA (backward masking). These results indicate that surround suppression in V4 neurons has considerable temporal width, which is longer than that previously reported in areas V1 and V2. When l compare the time course of suppression in V4 neurons with that in the perception in psychophysical experiments, I found that there were two differences. First, the inhibition occurred only in the positive SOA in the psychophysical experiments but the inhibition was found in both positive and negative SOA in the responses of V4 neurons. Secondly, the duration of inhibition was longer in the positive SOA in the perceptual metacontrast masking than in the activities of V4 neurons. These results indicate that the activities of V4 neurons do not parallel the perception in metacontrast masking. However, the longer duration of suppression of V4 neurons compared with neurons in V1 and V2 which are located ealier in the visual processing suggest that activities in V4 may represent an intermediate stage of conversion of visual signals which finally makes the time course of the neural responses resemblance to the perception in the metacontrast masking.","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481号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"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":"20 生理科学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"1999"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"KONDO, Hideki","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"9356","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","filename":"甲481_要旨.pdf","filesize":[{"value":"290.4 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨 / Abstract, Screening Result","url":"https://ir.soken.ac.jp/record/1112/files/甲481_要旨.pdf"},"version_id":"ec15b463-ac52-4203-a6ce-f713da095833"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲481_本文.pdf","filesize":[{"value":"2.9 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/1112/files/甲481_本文.pdf"},"version_id":"c09498f8-4991-4843-ab50-b63e1e89feb2"}]},"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":"Relation between the neuron activities in corticalarea V4 and the metacontrast masking","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Relation between the neuron activities in corticalarea V4 and the metacontrast masking"},{"subitem_title":"Relation between the neuron activities in corticalarea V4 and the metacontrast masking","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["22"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"1112","relation_version_is_last":true,"title":["Relation between the neuron activities in corticalarea V4 and the metacontrast masking"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T14:47:42.942942+00:00"}