眼球運動 Oculomotor System
P3-1-133 自閉症スペクトラム障害のハイリスク児における視線行動のパターンについて Gaze patterns in infants at risk for autism spectrum disorders ○金井智恵子1,2, 橋本龍一郎2,3, 山田貴志2, 神保大樹4, 一橋和義4, 岩波明2, 加藤進昌5 ○Chieko Kanai1,2, Ryuichiro Hashimoto2,3, Takashi Yamada2, Daiki Jinbo4, Kazuki Ichihashi4, Akira Iwanami2, Nobumasa Kato5 相模女子大・子ども教育1, 昭和大学・医・精神医学2, 首都大学東京大・人間科学・言語科学3, 昭和大・医・解剖学4, 昭和大・保健医療学5 Department of Education, Sagami Women's University, Kanagawa1, Department of Psychiatry, Showa University, Tokyo2, Cognitive Neuroscience of Language, Tokyo Metropolitan University, Tokyo3, Department of Anatomy, Showa University4, Showa University Graduate School of Nursing and Rehabiltaion, Tokyo5 Objectives: The development of biomarkers in autism spectrum disorders has had important for the early treatment of the symptoms of autism. Eye-tracking technology has been used to as an objective method for characterizing the early features of autism spectrum disorders. Some studies reported that children with autism spectrum disorders showed specific gaze patterns comparing with typical developing children. However, there are few studies to investigate gaze patterns in infants at risk for autism spectrum disorders below the age of three years old.Methods: A total of 88 participants (mean 17.5 month old (9.1); 67 boys, 8 girls: 80 typical developing children, 8 infants at risk for autism spectrum disorders) participated in the study. An inclusion criterion for the infants at risk for autism spectrum disorders was family history of autism spectrum disorder. To clarify core autism spectrum disorders gaze behaviours, we examined gaze patterns in infants at risk for autism spectrum disorders while infants viewed 50 seconds 4 movie video clips. The video depicts moving fractal figure patterns on 1 side of a video monitor and TV programs for infants, such as dancing or singing, on the other. Results: To compare between infants at risk for autism spectrum disorders and typical developing children, the infants at risk for autism spectrum disorders prefer significantly viewing the TV programs in the first and fourth movie video clips. The infants at risk for autism spectrum disorders also exhibit abnormal gaze patterns and spend a shorter time looking in the face areas than typical developing children while viewing the TV programs.Conclusions: These results might be helpful to detect early features of autism spectrum disorders	P3-1-134 補足眼野で生成される予測誤差は探索と知識利用の切り替えを引き起こす Multiple prediction errors in the supplementary eye field drive the exploration-exploitation transitions during an oculomotor search task ○川口典彦1,2, 坂本一寛3, 斎藤尚宏1, 古沢義人1, 丹治順4, 青木正志2, 虫明元1,5 ○Norihiko Kawaguchi1,2, Kazuhiro Sakamoto3, Naohiro Saito1, Yoshito Furusawa1, Jun Tanji4, Masashi Aoki2, Hajime Mushiake1,5 東北大院・医・生体システム生理1, 東北大・神経内科2, 東北大・電気通信研3, 東北大・脳科学センター4 Dept. of Physiol., Grad. Sch. of Med., Tohoku Univ., Sendai, Japan1, Dept. of Neurology, Tohoku Univ., Sendai, Japan2, Research Inst. of Electrical Communication, Tohoku Univ., Sendai, Japan3, Brain Science Center, Tohoku Univ., Sendai, Japan4, CREST, JST, Tokyo, Japan5 Balancing exploration and exploitation is essential for achieving optimal behavior in an uncertain environment. The supplementary eye field (SEF) is considered a higher-order oculomotor area. However, whether the SEF contributes to manage the exploration-exploitation trade-off remains to be elucidated. To answer this question, we introduced an oculomotor search task in which a monkey explored two valid targets among four identical stimuli and made saccades to the two targets alternately. We hypothesized that the SEF would encode multiple prediction errors and guide subsequent behavior. To test this hypothesis, we developed a reinforcement learning model that updates the prediction values of negative and positive outcomes by tracking behavioral consequences. Using this model, we identified two representative groups of neurons. One group responded to negative feedback, especially at the beginning of the exploration, and its activities were associated with an oculomotor search pattern specific to the exploration phase. The second group responded to positive outcomes during the last phase of exploration, and its activities were related to a search pattern specific to the exploitation phase. These results suggest that the SEF controls the exploration-exploitation trade-off by encoding multiple prediction errors and adjusting eye movement patterns.
P3-1-135 等価選択肢間の選択における前頭連合野ニューロンの役割 Role of the primate prefrontal neurons in choosing equally valuable actions ○望月圭1,2, 船橋新太郎1,3 ○Kei Mochizuki1,2, Shintaro Funahashi1,3 京都大院・人環1, 日本学術振興会（特別研究員）2, 京都大学 こころの未来研究センター3 Grad Sch of Human and Environmental Studies, Kyoto Univ, Kyoto, Japan1, JSPS (Research Fellow), Tokyo, Japan2, Kokoro Res Ctr, Kyoto Univ, Kyoto, Japan3 In everyday lives, we often need to make decisions between equally valuable actions (e.g. entering from left or right door of the same building). This decision process is called "free choice", under which the amount of reward is identical regardless of the actor's behavior. Although we can immediately make a choice under such situations, how this speeded decision is achieved in the brain is not yet fully investigated. In the current study, we recorded neuronal activity from primate prefrontal cortex (PFC) during free choice behavior to examine its biological underpinnings. We used two types of saccade tasks. In the Instructed Choice Task (ICT), the monkeys were shortly presented with a visual cue and required to make a memory-guided saccade toward that direction after the delay. In the Free Choice Task (FCT), two identical cues were simultaneously presented in the cue period. The monkeys could respond to either of the two locations and get the same amount of reward. Accordingly, in FCT trials, the monkeys were required to choose the response direction by themselves. We examined the activity of PFC neurons with transient visual response. In the FCT, these neurons were more activated in trials when their preferred direction was eventually chosen. Differential activation was evident even hundreds milliseconds before the presentation of the cues. These results suggest that the fluctuation of firing before cue could influence the animals' decision by biasing the representation of the visual stimuli in the beginning of the trial, and thus could be advantageous to accelerate the decision. Furthermore, this effect of fluctuated activity was different between neuron subtypes (putative pyramidal cells and interneurons). We propose that the multiple subtypes of neurons with different levels of fluctuation allow coexistence of both variated firing and stable representation in the circuitry, and thus have a key role in speeded decision making between equally valuable actions.	P3-1-136 サリエンシー・マップに基づいた視覚補填を目指して Saliency-guided visual prosthesis: design and simulation ○吉田正俊1,2 ○Masatoshi Yoshida1,2, Richard Veale3 自然科学研究機構 生理学研究所 認知行動発達1, 総合研究大学院大学2, インディアナ大学3 Dept Develop Physiol, National Institute for Physiological Sciences, Okazaki1, School of Life Science, The Graduate University for Advanced Studies, Hayama2, Cognitive Science Program, Indiana University, Bloomington, USA3 What can we do to restore visual function to patients with damage in the visual cortex? One approach is to implement a visual prosthesis directly in the visual cortex using electrical microstimulation. However, this approach has disadvantages such as the difficulty of implanting electrodes to cover the entire visual field and possible interference of vision by generated phosphenes. Recently the authors showed that a computational saliency model predicts gaze during free-viewing of monkeys with damage in the primary visual cortex (Yoshida et.al. 2012). We quantified which visual features are most active in the lesioned monkeys; motion, luminance and color features contributed to residual guidance of eye movement, while orientation features did not. Based on these findings, we propose a saliency-guided visual prosthesis in which the superior colliculus is stimulated to drive attention rather than to evoke phosphenes. Since the visual field is represented within a 2 mm by 2 mm area in the superior colliculus, it is easier to cover the entire visual field with implanted electrodes. The proposed prosthesis operates in a tight loop with three stages. 1) A saliency map in collicular coordinates is continuously calculated from a real-time camera stream and eye tracking. 2) The map is passed through a computational filter to produce the stimulation parameters of the implanted electrodes. 3) The stimulation is applied. The filter from step 2 is predetermined via calibration sessions in which eye movements of monkeys during free-viewing are perturbed by spatiotemporal patterns of electrical microstimulation through the electrodes implanted in the bilateral superior colliculus. As a proof-of-concept, we build a simple simulation to decide how many electrodes are necessary to reconstruct the desired spatiotemporal patterns of activity in the superior colliculus. Our simulation study demonstrates that such a system is able to restore orientation information in a lesioned monkey.
P3-1-137 ヒトマイクロサッケードと随意まばたき運動の準備状態との関係 Interactions between microsaccades and the preparation of repetitive volitional blinks ○浅原舜平1,2, 田中文哲1,2, 松尾有華3, 査凌3, 岡田研一2, 渡邊雅之4,5, 小林康1,2,6,7,8 ○Shumpei Asahara1,2, Fumiaki Tanaka1,2, Yuka Matsuo3, Ling Zha3, Ken-ichi Okada2, Masayuki Watanabe4,5, Yasushi Kobayashi1,2,6,7,8 大阪大学　基礎工学部　システム科学科　生物工学コース1, 大阪大学大学院　生命機能研究科　脳神経工学講座2, 大阪大学大学院　医学系研究科3, 関西医科大学　生理学第二4, カナダクイーンズ大学　神経科学研究センター5, JSTさきがけ6, 脳情報通信融合研究センター7, 大阪大学社会経済研究所　行動経済学研究センター8 Division of Biophysical Engineering, Dept of Systems Sci, School of Engineering Sci, Osaka Univ, Osaka1, Graduate School of Frontier Biosciences, Osaka Univ, Osaka2, Dept of Social and Environmental Medicine, Grad School of Medicine, Osaka Univ, Osaka3, Dept of Physiology, Kansai Medical Univ, Osaka4, Centre for Neuroscience Studies, Queens Univ, Canada5, PRESTO, The Japan Science and Technology Agency, Saitama6, Center for Information and Neural Network, Osaka7, Research Center for Behavioral Economics, Osaka Univ, Osaka8 Our eyes move constantly, even when we try to fixate our gaze. Microsaccades, which are the fastest and largest fixational eye movements, have important roles in visual perception. Previous studies suggested that, the microsaccades are sensitive to volitional action preparation, such that the probability of microsaccades gradually decreased toward stimulus appearance in successfully completed pro- and anti-saccade trials, but increased in erroneous trials. However, it remains unclear whether the microsaccade reflect preparatory process of large saccade or preparatory process of general volitional movement. Thus here we examined interactions between microsaccade and another type of movement, volitional eye blink. We recorded eye movement of healthy adult human subjects using an eye tracking system based on a high-speed video camera system, and detected microsaccade and volitional blink. Subjects were instructed to produce volitional blink with acoustic tone signals. There were three different task conditions. Subjects performed volitional blink; (1) guided by constant periodic tone signals; (2) initially guided by constant tone signals, and after tone instruction ended, subjects performed volitional blink at the same rate without tone signals; (3) with random tone signals. Under these three different preparatory conditions, we analyzed the occurrence of microsaccades before and after volitional blink. We also analyzed the effect of microsaccades on the temporal pattern of repetitive volitional blinks and the time dependent changes in the microsaccade parameters to examine the effect of fatigue, sleepiness or concentration state of subjects.	P3-1-138 マイクロサッカード頻度と瞳孔径変動の解析によるSEMの発生に先立って生じる覚醒水準変動の評価 An arousal level assessment by analyzing microsaccade rate and pupil fluctuation in preceding period of slow eye movements ○本田彰吾1, 小濱剛2, 吉田久2, 田中達郎1 ○Shougo Honda1, Takeshi Kohama2, Hisashi Yoshida2, Tatsurou Tanaka1 近畿大学大学院　生物理工学研究科　電子システム情報工学専攻1, 近畿大学　生物理工学部　システム生命工学科2 Dept. Electronic System and Information Engineering, Graduate School of Biology-Oriented Science and Technology,Univ. Kinki , Wakayama Japan1, Dept. Computational System Biology, Faculty of Biology-Oriented Science and Technology,Univ. Kinki , Wakayama Japan2 It is well known that a decline of arousal level causes of poor performance of movements or judgments while doing VDT work, driving, and so on. Previous studies show that slow eye movements (SEMs) could be a candidate for an indicator of decline of arousal. However, since SEMs appear just prior to sleep onset, it is not sufficient to evaluate the transition of arousal states. In this study, we demonstrate that fixation eye movements and pupil fluctuations, while subjects continuously maintain their eyes on a small fixation target cross, are both affected by lowering the subjects' arousal level just before appearance of SEMs. Our SEM detection method is based on Shin et al.'s method (Shin et al, 2004) which focuses on amplitude and averaged velocity profile of eye movement data recorded by electrooculography (EOG) . Their method is sufficiently precise to detect SEMs at one moment, but it can't discriminate the period of SEMs which sustain for several seconds. We modified Shin et al.'s method to determine the period of sustaining SEMs using a general eye tracker of which spacial resolution is high enough to detect microsaccades. To examine the accuracy of SEM period detection, the start and end point of each SEM period were judged subjectively by six participants for the use as a gold standard. The errors of thestart and end point were -2.3[s] and 3.2[s] respectively. After SEM detection, we analyzed the transition of microsaccade rate and pupil fluctuation immediately before each SEM period. The microsaccade rate was determined as the number of occurrences of microsaccades within a given time period. The pupil fluctuation was defined as a time series of the regression coefficient fitted for the pupil diameter transition. The results indicate that longitudinal miosis of pupil diameter and a gradual rise of microsaccade rate are observed prior to each SEM period. This suggests that arousal level may be evaluated by monitoring eye movements and pupil fluctuations.
P3-1-139 平均二乗変位量特性を再現する固視微動の数式モデル A mathematical model for reproducing mean square displacement profile of fixation eye movements ○徳留健1, 小濱剛2, 吉川昭3, 吉田久2 ○Ken Tokudome1, Takeshi Kohama2, Sho Kikkawa3, Hisashi Yshida2 近畿大学大学院 生物理工学研究科 電子システム情報工学1, 近畿大学生物理工学部 システム生命科学科2, 近畿大学生物理工学部3 Department of Electronic System and Information Engineering, Graduate School of Biology-Oriented Science and Technology, kinki University1, Department of Camputational Systems Biology, Faculty of Biology-Oriented Science and Techonology, Kinki University2, Department of Camputational Systems Biology, Kinki University3 Mean Square Displacement (MSD) is known as a statistical index which indicates two different time scale properties in fixational eye movements (Engbert & Kliegl, 2004). Fixational eye movements enlarges fixation errors on a short time scale, while it reduces the errors and stays within the fixed limit on a long time scale.This means that some external force must exist, such as center-of-pressure in human posture control. Engbert et al. proposed a mathematical model which can reproduce these features of fixational eye movements (Engbert et al., 2011). The model is based on a self-avoiding random walk process with a potential field in which fixated points are stuck for use as self-generated activation distribution. They suppose that this activation field corresponds to the motor map of the superior colliculus. However, because the motor map depends on the retinotopic map of which the origin always coincides with the current gaze position. In this study, we propose a model which can reproduce two different time scales in fixational eye movements. The proposed model is based on the classical hypothesis that microsaccades correct fixation errors caused by fixational fluctuation called drifts and tremor, and are under the feedback control system of eye movements. We have generated a Brownian motion with Gaussian noise, as drifts and tremor, and defined the boundary of acceptable error to maintain the range of displacement of a trajectory. If the trajectory goes over the boundary, a correction signal is generated to reduce the fixation errors with a latency time. This latency time is considered neural signaling in the optic pathway from the retina to the brainstem via the superior colliculus, and this correction signal is regarded as a microsaccade. The simulation results suggest that the feedback error correction with certain latency might contribute to maintaining gaze position sticking around the fixation target and yeild the MSD profile of fixation eye movements.

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