This research implements a random dot kinematogram(RDK)using virtual reality(VR)and analyzes the results based on normal subjects.Visual motion perception is one of visual functions localized to a specific cortical ar...This research implements a random dot kinematogram(RDK)using virtual reality(VR)and analyzes the results based on normal subjects.Visual motion perception is one of visual functions localized to a specific cortical area,the human motion perception area(human analogue for the middle temporal/middle superior temporal area)located in the parieto–occipito–temporal junction of the human brain.The RDK measures visual motion perception capabilities.The stimuli in conventional RDK methods are presented using a monitor screen,so these devices require a spacious dark room for installation and use.Recently,VR technology has been implemented in different medical domains.The test method proposed in this study include a VR-based RDK that can independently measure human motion perception abilities without any spatial constraints via a VR head-mounted display.Subsequently,the VR-based RDK was implemented,and the visual perception abilities of the normal subjects were measured based on varying coherences.In both screen-and VR-based RDK tests,the easier the stimulus is,the higher the correct answer rate and the shorter the reaction time.No significant differences in coherence thresholds were observed between the two test methods.The VRbased RDK proposed in this study can be used as a diagnosis tool for visual motion perception and neurodegenerative disorders affecting the posterior region of the brain.展开更多
Apparent motion stimulus induces visual perception of smooth motion even though there is no speed information. We examined whether human brain response as measured by magnetoencephalography carries direction informati...Apparent motion stimulus induces visual perception of smooth motion even though there is no speed information. We examined whether human brain response as measured by magnetoencephalography carries direction information in the visually presented apparent motion of a randomdot pattern in a similar manner as continuous motions that have speed and direction information. Although there was no significant effect of motion direction on the peak response latency and amplitude, mutual information entropy (IE) significantly increased after the motion onset at approximately 36 ms after the response latency in 41% of the evaluations. Detailed analysis of the data from five subjects who participated in both the present apparent motion and our previous coherent motion studies revealed that the maximum IE latency (delay) for apparent motion was significantly longer than that for coherent motion, although the mean maximum IE was the same. The results indicate that direction is represented in the response waveform evoked by apparent motion but the manner is different from that for coherent motion probably due to the distinct neural processes engaged only for the apparent motion perception. We consider that direction and speed can be processed separately in the human brain because direction information was generated without speed information for the perception of apparent motion.展开更多
Identifying perceptual thresholds is critical for understanding the mechanisms that underlie signalevolution. Using computer-animated stimuli, we examined visual speed sensitivity in the Jackydragon Amphibolurus muric...Identifying perceptual thresholds is critical for understanding the mechanisms that underlie signalevolution. Using computer-animated stimuli, we examined visual speed sensitivity in the Jackydragon Amphibolurus muricatus, a species that makes extensive use of rapid motor patterns in so-cial communication. First, focal lizards were tested in discrimination trials using random-dot kine-matograms displaying combinations of speed, coherence, and direction. Second, we measuredsubject lizards＇ ability to predict the appearance of a secondary reinforcer （1 of 3 differentcomputer-generated animations of invertebrates： cricket, spider, and mite） based on the directionof movement of a field of drifting dots by following a set of behavioural responses （e.g., orientingresponse, latency to respond） to our virtual stimuli. We found an effect of both speed and coher-ence, as well as an interaction between these 2 factors on the perception of moving stimuli.Overall, our results showed that Jacky dragons have acute sensitivity to high speeds. We then em-ployed an optic flow analysis to match the performance to ecologically relevant motion. Our resultssuggest that the Jacky dragon visual system may have been shaped to detect fast motion. Thispre-existing sensitivity may have constrained the evolution of conspecific displays. In contrast,Jacky dragons may have difficulty in detecting the movement of ambush predators, such as snakesand of some invertebrate prey. Our study also demonstrates the potential of the computer-animated stimuli technique for conducting nonintrusive tests to explore motion range and sensitiv-ity in a visually mediated species.展开更多
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.2019R1F1A1062752 and 2019R1C1C1006539)and was supported by the Soonchunhyang University Research Fund.
文摘This research implements a random dot kinematogram(RDK)using virtual reality(VR)and analyzes the results based on normal subjects.Visual motion perception is one of visual functions localized to a specific cortical area,the human motion perception area(human analogue for the middle temporal/middle superior temporal area)located in the parieto–occipito–temporal junction of the human brain.The RDK measures visual motion perception capabilities.The stimuli in conventional RDK methods are presented using a monitor screen,so these devices require a spacious dark room for installation and use.Recently,VR technology has been implemented in different medical domains.The test method proposed in this study include a VR-based RDK that can independently measure human motion perception abilities without any spatial constraints via a VR head-mounted display.Subsequently,the VR-based RDK was implemented,and the visual perception abilities of the normal subjects were measured based on varying coherences.In both screen-and VR-based RDK tests,the easier the stimulus is,the higher the correct answer rate and the shorter the reaction time.No significant differences in coherence thresholds were observed between the two test methods.The VRbased RDK proposed in this study can be used as a diagnosis tool for visual motion perception and neurodegenerative disorders affecting the posterior region of the brain.
文摘Apparent motion stimulus induces visual perception of smooth motion even though there is no speed information. We examined whether human brain response as measured by magnetoencephalography carries direction information in the visually presented apparent motion of a randomdot pattern in a similar manner as continuous motions that have speed and direction information. Although there was no significant effect of motion direction on the peak response latency and amplitude, mutual information entropy (IE) significantly increased after the motion onset at approximately 36 ms after the response latency in 41% of the evaluations. Detailed analysis of the data from five subjects who participated in both the present apparent motion and our previous coherent motion studies revealed that the maximum IE latency (delay) for apparent motion was significantly longer than that for coherent motion, although the mean maximum IE was the same. The results indicate that direction is represented in the response waveform evoked by apparent motion but the manner is different from that for coherent motion probably due to the distinct neural processes engaged only for the apparent motion perception. We consider that direction and speed can be processed separately in the human brain because direction information was generated without speed information for the perception of apparent motion.
文摘Identifying perceptual thresholds is critical for understanding the mechanisms that underlie signalevolution. Using computer-animated stimuli, we examined visual speed sensitivity in the Jackydragon Amphibolurus muricatus, a species that makes extensive use of rapid motor patterns in so-cial communication. First, focal lizards were tested in discrimination trials using random-dot kine-matograms displaying combinations of speed, coherence, and direction. Second, we measuredsubject lizards＇ ability to predict the appearance of a secondary reinforcer （1 of 3 differentcomputer-generated animations of invertebrates： cricket, spider, and mite） based on the directionof movement of a field of drifting dots by following a set of behavioural responses （e.g., orientingresponse, latency to respond） to our virtual stimuli. We found an effect of both speed and coher-ence, as well as an interaction between these 2 factors on the perception of moving stimuli.Overall, our results showed that Jacky dragons have acute sensitivity to high speeds. We then em-ployed an optic flow analysis to match the performance to ecologically relevant motion. Our resultssuggest that the Jacky dragon visual system may have been shaped to detect fast motion. Thispre-existing sensitivity may have constrained the evolution of conspecific displays. In contrast,Jacky dragons may have difficulty in detecting the movement of ambush predators, such as snakesand of some invertebrate prey. Our study also demonstrates the potential of the computer-animated stimuli technique for conducting nonintrusive tests to explore motion range and sensitiv-ity in a visually mediated species.
