{"created":"2023-06-20T13:21:05.382454+00:00","id":1183,"links":{},"metadata":{"_buckets":{"deposit":"081cca69-3065-4f21-ba68-d9343e4c2d16"},"_deposit":{"created_by":1,"id":"1183","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"1183"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00001183","sets":["2:430:22"]},"author_link":["0","0","0"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"安田, 正治"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ヤスダ, マサハル"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2007-03-23"}]},"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":"Inferior temporal (IT) cortex of the monkey is the final stage of the ventral stream that is concerned with the processing of color and shape information.  Lesion studies indicated that IT cortex plays an important role in color perception.  Previous recording studies showed that there were many color selective neurons in the anterior two-thirds of IT cortex (area TE).  As for the posterior IT (PIT) cortex, although some imaging studies reported that this area is activated by color stimuli, no neural recording experiments have been conducted to systematically study color selectivity of PIT neurons.  In the present study, we recorded neuron activities from PIT cortex and examined color and shape selectivity using a set of color stimuli that systematically distributed in the color space and a set of geometrical patterns.  Neurons were recorded from three hemisphere of two macaque monkeys while each animal performed a visual fixation task.   Recording chambers were placed to cover the lateral surface of the PIT cortex anterior to the inferior occipital sulcus.  <br />We recorded 727 single and multiple neurons from PIT of two monkeys, and examined the color selectivity, shape selectivity and extent of the receptive field (RF) of each neuron, and studied how these response properties distributed in PIT cortex.  We found that many color-selective neurons distributed throughout the PIT cortex examined.  However, the color selective properties were not homogeneous across the PIT cortex.  We found that neurons in the ventral part of PIT cortex tended to have sharper color tuning than those in the dorsal part of PIT cortex.   We also found that many PIT neurons exhibit shape selectivity, and that color selective neurons with and without shape selectivity were intermingled in either the dorsal and ventral region of PIT cortex.  This suggests that the processing of color information and shape information takes place in close relationship in PIT. <br />We quantitatively tested the color and/or shape selectivity in 197 single neurons.  In these neurons, we quantified the selectivity to color and shape stimuli of each neuron using two indices.  First, selectivity index was calculated for each neuron to quantify how well a cell discriminated the most-preferred stimulus from the least-preferred stimulus in each set of stimuli.  The value of selectivity index and the statistical significance of the variation in the responses to the stimulus sets were used to classify a neuron as selective or not.    Secondly, we calculated sparseness index to quantify the sharpness of stimulus selectivity.  This index indicates the degree to which responses evenly distributed across the set of stimuli.  We mapped the distribution of these indices across the PIT cortex, and found that color selective neurons with sharp color tuning (color sparseness index < 0.7) were concentrated in the ventral part of PIT cortex examined and we named this region as PIT color area (PITC). In PITC, each neuron had sharp color tuning and represented only a restricted area of the color space, but the population of such sharply color-tuned neurons in PITC as a whole represented the entire color space. Neurons located out of PITC also had color selectivity but they tended to have broader color tuning than those in PITC. With regard to the strength and sharpness of shape selectivity, there was no clear difference between neurons located in and out of PITC.  <br />We mapped the RFs in PIT and found that there was crude retinotopic organization in PITC.  Neurons in the dorsal part of PITC had RFs containing the foveal center.  In the ventral part, the eccentricity of RFs increased and the RFs in the anterior and posterior part represented the lower and upper visual field, respectively.  This retinotopy corresponded well to what Boussaoud et al. (1991) previously reported in PIT.  One important difference between their previous result and our present result is that, although these authors reported that the retinotopic map covered the entire region of the lateral surface of PIT cortex ventral to STS, we found that clear retinotopic organization was restricted within a part of PIT and this area corresponded to the region where neurons having sharp color selectivity were concentrated, namely PITC.  Moreover, the position of the retinotopic map differed between individual hemispheres, and the positional shift seemed to be in coincident with the variation of the position of PMTS.  The present results strongly suggest that there is a circumscribed region in and around PMTS that has crude retinotopic organization and that is involved in the processing of color information. <br />As the luminance contrast is an important factor influencing the perceived color, we used two color stimulus sets at two different luminance contrasts; one is darker and the other is brighter than the background.  Many PITC neurons changed their responses to color stimuli depending on their luminance contrast.  When we considered the color representation with the activities of the entire population of neurons, we found that the responses to red and blue were stable across two luminance contrasts while the responses to un-saturated colors such as white, gray, and black were variable with the change in luminance contrast.  This seems consistent with the fact that the perceived color of un-saturated colors significantly change depending on the luminance contrast whereas that of blue and red do not change by the change in the luminance contrast. These results suggest that activities of color selective neurons in PIT cortex is strongly related to color perception. <br />","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1069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":"2006"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"YASUDA, Masaharu","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"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1069_要旨.pdf","filesize":[{"value":"289.1 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨","url":"https://ir.soken.ac.jp/record/1183/files/甲1069_要旨.pdf"},"version_id":"598af749-a397-4acb-8eec-1eebc8fa6693"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1069_本文.pdf","filesize":[{"value":"1.2 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/1183/files/甲1069_本文.pdf"},"version_id":"634e6a3e-2d7b-476d-9af0-63b7c09fbbaa"}]},"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":"The color selectivity of neurons in posterior inferior temporal cortex of macaque monkey","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"The color selectivity of neurons in posterior inferior temporal cortex of macaque monkey"},{"subitem_title":"The color selectivity of neurons in posterior inferior temporal cortex of macaque monkey","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":"1183","relation_version_is_last":true,"title":["The color selectivity of neurons in posterior inferior temporal cortex of macaque monkey"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-06-20T16:08:19.009057+00:00"}