理學院: 心理學研究所指導教授: 陳建中游為翔Yu, Wei-HsiangWei-HsiangYu2017-03-022018-06-282017-03-022018-06-282015http://ntur.lib.ntu.edu.tw//handle/246246/272034過去動物生理研究已經發現單一大腦視覺神經細胞即可以利用其分別於左、右兩眼的接受域在對應視野區域上位置差異或相位角(接受域之內部結構)差異處理雙眼像差。Anzai, Ohzawa, & Freeman 等人1999 年的研究之結果主張在單一神經中，左右眼接受域的相位像差才是神經編譯雙眼像差的主要因素，而位置像差則為其次。然而，許多大腦功能的研究顯示，個體的行為或是知覺表徵為透過一群神經元共同進行表徵(如手部移動的方向或是對於物體運動方向的判斷)，但過去對於雙眼像差的研究多半著重於神經元層次，並未太多研究探討視覺神經群如何表徵雙眼像差。故，本研究旨於探討視覺神經群如何透過其結構編譯雙眼像差。透過磁振造影並結合神經群接受域模型Dumoulin & Wandell, 2008)模擬大腦視覺神經群分別在接受左⣺77;右眼的低對比刺激下之群接受域。本研究結果發現群接受域的位置像差在整個視覺皮質中並無顯著差異於零，顯示視覺皮質整體並無特定偏好交叉(cross)或反交叉(uncross)，與過去行為研究相符。我們進一步利用 資料模擬方法計算各別視覺神經群的左、右群接受域之變異，用以估計每個視覺神經群所對應的位置像差。結果顯示，不論在初級(V1)或次級(V2⣺77;V3)視覺皮質，皆有大量神經群顯著對應到特定雙眼像差。另外，神經群的位置像差隨視中央至外視野增加，其與心理物理實驗之結果相符。綜合本研究之結果，雖然本研究並無分析群接受域內部結構差異是否能編譯雙眼像差，但由於左、右群接受域在位置上已經有顯著差異，故可推斷雙眼像差在群神經階層可透過左、右群接受域的位置像差進行編譯。Electrophysiological evidence suggests that the visual cortical neurons encode disparity through either position or phase difference between left and right receptive fields. Since Anzai, Ohzawa, & Freeman (1999a) proposed that the visual cortical neurons encode binocular disparity mainly rely on the receptive fields phase difference but less position difference, how group of neurons encode binocular disparity remains unclear. Here, we investigated the position disparity model at the population level with fMRI. Retinotopic BOLD activations were measured under binocular and two monocular (the left and right eye) viewing conditions with low contrast checkerboard patterns and fitted to a population receptive field (pRF) model (Dumoulin & Wandell, 2008). The position disparity was measured by the distance between centers of left and right pRFs. Also, a bootstrap method was used to generate simulated data to estimate variations of pRFs of each viewing condition of each voxel. This allows us to test binocular disparity of each neural population statistically. Our results showed that distributions of horizontal and vertical disparities of visual cortical neurons do not significant deviate from zero, suggesting that visual system does not prefer to any disparity. Moreover, simulations showed that a bunch of binocular voxels (30% on average) have a significant pRFs position shift (at α =.01 level), suggesting a position coding of disparity at the population level. Also, both horizontal and vertical disparities increase with the eccentricity in all visual cortices, which consistent with psychophysics’ results that the fusion limit is positive correlate to the eccentricity. Together, our results revealed (A) a position coding of binocular disparity and (B) neural evidence for increasing fusion limit with the eccentricity at the population level.2755789 bytesapplication/pdf論文公開時間: 2020/2/4論文使用權限: 同意有償授權(權利金給回饋本人)雙眼像差fMRIpopulation receptive fieldBinocular disparitythesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/272034/1/ntu-104-R01227113-1.pdf