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BMJ Open Ophthalmology May 2024To investigate the recurrent non-arteritic retinal artery occlusion (RAO) in the same or opposite eye.
OBJECTIVES
To investigate the recurrent non-arteritic retinal artery occlusion (RAO) in the same or opposite eye.
METHODS
We searched the RAO registry at Seoul National University Bundang Hospital and included patients with recurrent RAO in the present study. Ophthalmic and systemic features were analysed to identify risk factors and visual outcomes.
RESULTS
Of the 850 patients in the non-arteritic RAO cohort, 11 (1.3%) experienced a second RAO recurrence, either in the same (5 patients; 0.6%) or opposite (6 patients; 0.7%) eye. The same eye group experienced an earlier recurrence (1-2 months, median 1 month) than the opposite eye group, where the time to recurrence was notably longer (8-66 months, median 22 months). Best corrected visual acuity (BCVA) in the same eye group decreased after the recurrence of RAO. In the same eye group, initial BCVA ranged from 20/200 to counting fingers (CF), while BCVA during RAO recurrence ranged from CF to hand motion. When RAO recurred in the opposite eye, the reduction in visual acuity was less severe than the reduction of the initial episode: initial episode ranged from 20/400 to light perception and recurrent episode ranged from 20/25 to 20/400. Patients exhibited varying degrees of carotid (81.8%) and cerebral (9.1%) artery occlusions. Additionally, one patient in each group (total 2 patients, 18.2%) experienced a stroke 6 months after RAO recurrence.
CONCLUSIONS
Since the RAO recurrences could lead to devastating visual impairment, it is essential to emphasise the importance of risk factor screening to patients while collaborating with neurologists and cardiologists.
Topics: Humans; Retinal Artery Occlusion; Recurrence; Male; Female; Visual Acuity; Middle Aged; Aged; Risk Factors; Retrospective Studies; Adult; Registries; Fluorescein Angiography; Aged, 80 and over; Tomography, Optical Coherence; Follow-Up Studies
PubMed: 38816011
DOI: 10.1136/bmjophth-2024-001636 -
Journal of Vision May 2024Temporal asynchrony is a cue for the perceptual segregation of spatial regions. Past research found attribute invariance of this phenomenon such that asynchrony induces...
Temporal asynchrony is a cue for the perceptual segregation of spatial regions. Past research found attribute invariance of this phenomenon such that asynchrony induces perceptual segmentation regardless of the changing attribute type, and it does so even when asynchrony occurs between different attributes. To test the generality of this finding and obtain insights into the underlying computational mechanism, we compared the segmentation performance for changes in luminance, color, motion direction, and their combinations. Our task was to detect the target quadrant in which a periodic alternation in attribute was phase-delayed compared to the remaining quadrants. When stimulus elements made a square-wave attribute change, target detection was not clearly attribute invariant, being more difficult for motion direction change than for luminance or color changes and nearly impossible for the combination of motion direction and luminance or color. We suspect that waveform mismatch might cause anomalous behavior of motion direction since a square-wave change in motion direction is a triangular-wave change in the spatial phase (i.e., a second-order change in the direction of the spatial phase change). In agreement with this idea, we found that the segregation performance was strongly affected by the waveform type (square wave, triangular wave, or their combination), and when this factor was controlled, the performance was nearly, though not perfectly, invariant against attribute type. The results were discussed with a model in which different visual attributes share a common asynchrony-based segmentation mechanism.
Topics: Humans; Motion Perception; Photic Stimulation; Space Perception; Color Perception; Cues; Adult
PubMed: 38814934
DOI: 10.1167/jov.24.5.15 -
Frontiers in Plant Science 2024The application of autonomous navigation technology of electric crawler tractors is an important link in the development of intelligent greenhouses. Aiming at the...
The application of autonomous navigation technology of electric crawler tractors is an important link in the development of intelligent greenhouses. Aiming at the characteristics of enclosed and narrow space and uneven ground potholes in greenhouse planting, to improve the intelligence level of greenhouse electric crawler tractors, this paper develops a navigation system of electric crawler tractors for the greenhouse planting environment based on LiDAR technology. The navigation hardware system consists of five modules: the information perception module, the control module, the communication module, the motion module, and the power module. The software system is composed of three layers: the application layer, the data processing layer, and the execution layer. The developed navigation system uses LiDAR, Inertial Measurement Unit (IMU) and wheel speed sensor to sense the greenhouse environment and the crawler tractor's information, employs the Gmapping algorithm to build the greenhouse environment map, and utilizes the adaptive Monte Carlo positioning algorithm for positioning. The simulation test of different global path planning algorithms in Matlab shows that the A* algorithm obtains the optimal overall global path. In the scene of map 5, the path planned by the A* algorithm is the most significant, and the number of inflection points is reduced by 40.00% and 87.50%, respectively; meanwhile, the path length is the same as that of the Dijkstra algorithm, but the runtime is reduced by 68.87% and 81.49%, respectively; compared with the RRT algorithm, the path length is reduced by 7.27%. Therefore, the A* algorithm and the Dynamic Window Approach (DWA) method are used for tractor navigation and obstacle avoidance, which ensures global path optimality while also achieving effective local path planning for obstacle avoidance. The test results suggest that the maximum lateral deviation of the built map is 6 cm, and the maximum longitudinal deviation is 16 cm, which meets the requirement of map accuracy. Additionally, the results of the navigation accuracy test indicate that the maximum lateral deviation of navigation is less than 13 cm, the average lateral deviation is less than 7 cm, and the standard lateral deviation is less than 8 cm. The maximum heading deviation is less than 14°, the average heading deviation is less than 7°, and the standard deviation is less than 8°. These results show that the developed navigation system meets the navigation accuracy requirements of electric crawler tractors in the greenhouse environment.
PubMed: 38812735
DOI: 10.3389/fpls.2024.1377269 -
Science Advances May 2024Fluctuations in the activity of sensory neurons often predict perceptual decisions. This connection can be quantified with a metric called choice probability (CP), and...
Fluctuations in the activity of sensory neurons often predict perceptual decisions. This connection can be quantified with a metric called choice probability (CP), and there is a longstanding debate about whether CP reflects a causal influence on decisions or an echo of decision-making activity elsewhere in the brain. Here, we show that CP can reflect a third variable, namely, the movement used to indicate the decision. In a standard visual motion discrimination task, neurons in the middle temporal (MT) area of primate cortex responded more strongly during trials that involved a saccade toward their receptive fields. This variability accounted for much of the CP observed across the neuronal population, and it arose through training. Moreover, pharmacological inactivation of MT biased behavioral responses away from the corresponding visual field locations. These results demonstrate that training on a task with fixed sensorimotor contingencies introduces movement-related activity in sensory brain regions and that this plasticity can shape the neural circuitry of perceptual decision-making.
Topics: Animals; Visual Cortex; Decision Making; Macaca mulatta; Male; Neurons; Movement; Motion Perception; Saccades; Photic Stimulation
PubMed: 38809984
DOI: 10.1126/sciadv.adk7214 -
ELife May 2024In the 'double-drift' illusion, local motion within a window moving in the periphery of the visual field alters the window's perceived path. The illusion is strong even...
In the 'double-drift' illusion, local motion within a window moving in the periphery of the visual field alters the window's perceived path. The illusion is strong even when the eyes track a target whose motion matches the window so that the stimulus remains stable on the retina. This implies that the illusion involves the integration of retinal signals with non-retinal eye-movement signals. To identify where in the brain this integration occurs, we measured BOLD fMRI responses in visual cortex while subjects experienced the double-drift illusion. We then used a combination of univariate and multivariate decoding analyses to identify (1) which brain areas were sensitive to the illusion and (2) whether these brain areas contained information about the illusory stimulus trajectory. We identified a number of cortical areas that responded more strongly during the illusion than a control condition that was matched for low-level stimulus properties. Only in area hMT+ was it possible to decode the illusory trajectory. We additionally performed a number of important controls that rule out possible low-level confounds. Concurrent eye tracking confirmed that subjects accurately tracked the moving target; we were unable to decode the illusion trajectory using eye position measurements recorded during fMRI scanning, ruling out explanations based on differences in oculomotor behavior. Our results provide evidence for a perceptual representation in human visual cortex that incorporates extraretinal information.
Topics: Humans; Magnetic Resonance Imaging; Motion Perception; Female; Male; Visual Cortex; Adult; Illusions; Eye Movements; Young Adult; Photic Stimulation; Brain Mapping; Brain
PubMed: 38809774
DOI: 10.7554/eLife.76803 -
IScience Jun 2024Each sense serves a different specific function in spatial perception, and they all form a joint multisensory spatial representation. For instance, hearing enables...
Each sense serves a different specific function in spatial perception, and they all form a joint multisensory spatial representation. For instance, hearing enables localization in the entire 3D external space, while touch traditionally only allows localization of objects on the body (i.e., within the peripersonal space alone). We use an in-house touch-motion algorithm (TMA) to evaluate individuals' capability to understand externalized 3D information through touch, a skill that was not acquired during an individual's development or in evolution. Four experiments demonstrate quick learning and high accuracy in localization of motion using vibrotactile inputs on fingertips and successful audio-tactile integration in background noise. Subjective responses in some participants imply spatial experiences through visualization and perception of tactile "moving" sources beyond reach. We discuss our findings with respect to developing new skills in an adult brain, including combining a newly acquired "sense" with an existing one and computation-based brain organization.
PubMed: 38799571
DOI: 10.1016/j.isci.2024.109820 -
Scientific Reports May 2024Recent studies suggest that noninvasive imaging methods (EEG, MEG) in the human brain scalp can decode the content of visual features information (orientation, color,...
Recent studies suggest that noninvasive imaging methods (EEG, MEG) in the human brain scalp can decode the content of visual features information (orientation, color, motion, etc.) in Visual-Working Memory (VWM). Previous work demonstrated that with the sustained low-frequency Event-Related Potential (ERP under 6 Hz) of scalp EEG distributions, it is possible to accurately decode the content of orientation information in VWM during the delay interval. In addition, previous studies showed that the raw data captured by a combination of the occi-parietal electrodes could be used to decode the orientation. However, it is unclear whether the orientation information is available in other frequency bands (higher than 6 Hz) or whether this information is feasible with fewer electrodes. Furthermore, the exploration of orientation information in the phase values of the signal has not been well-addressed. In this study, we propose that orientation information is also accessible through the phase consistency of the occipital region in the alpha band frequency. Our results reveal a significant difference between orientations within 200 ms after stimulus offset in early visual sensory processing, with no apparent effect in power and Event-Related Oscillation (ERO) during this period. Additionally, in later periods (420-500 ms after stimulus offset), a noticeable difference is observed in the phase consistency of low gamma-band activity in the occipital area. Importantly, our findings suggest that phase consistency between trials of the orientation feature in the occipital alpha and low gamma-band can serve as a measure to obtain orientation information in VWM. Furthermore, the study demonstrates that phase consistency in the alpha and low gamma band can reflect the distribution of orientation-selective neuron numbers in the four main orientations in the occipital area.
Topics: Humans; Male; Electroencephalography; Female; Adult; Young Adult; Alpha Rhythm; Visual Perception; Photic Stimulation; Memory, Short-Term; Orientation; Gamma Rhythm; Brain; Evoked Potentials
PubMed: 38796618
DOI: 10.1038/s41598-024-62934-y -
Visual training after central retinal loss limits structural white matter degradation: an MRI study.Behavioral and Brain Functions : BBF May 2024Macular degeneration of the eye is a common cause of blindness and affects 8% of the worldwide human population. In adult cats with bilateral lesions of the central...
BACKGROUND
Macular degeneration of the eye is a common cause of blindness and affects 8% of the worldwide human population. In adult cats with bilateral lesions of the central retina, we explored the possibility that motion perception training can limit the associated degradation of the visual system. We evaluated how visual training affects behavioral performance and white matter structure. Recently, we proposed (Kozak et al. in Transl Vis Sci Technol 10:9, 2021) a new motion-acuity test for low vision patients, enabling full visual field functional assessment through simultaneous perception of shape and motion. Here, we integrated this test as the last step of a 10-week motion-perception training.
RESULTS
Cats were divided into three groups: retinal-lesioned only and two trained groups, retinal-lesioned trained and control trained. The behavioral data revealed that trained cats with retinal lesions were superior in motion tasks, even when the difficulty relied only on acuity. 7 T-MRI scanning was done before and after lesioning at 5 different timepoints, followed by Fixel-Based and Fractional Anisotropy Analysis. In cats with retinal lesions, training resulted in a more localized and reduced percentage decrease in Fixel-Based Analysis metrics in the dLGN, caudate nucleus and hippocampus compared to untrained cats. In motion-sensitive area V5/PMLS, the significant decreases in fiber density were equally strong in retinal-lesioned untrained and trained cats, up to 40% in both groups. The only cortical area with Fractional Anisotropy values not affected by central retinal loss was area V5/PMLS. In other visual ROIs, the Fractional Anisotropy values increased over time in the untrained retinal lesioned group, whereas they decreased in the retinal lesioned trained group and remained at a similar level as in trained controls.
CONCLUSIONS
Overall, our MRI results showed a stabilizing effect of motion training applied soon after central retinal loss induction on white matter structure. We propose that introducing early motion-acuity training for low vision patients, aimed at the intact and active retinal peripheries, may facilitate brain plasticity processes toward better vision.
Topics: Animals; White Matter; Cats; Magnetic Resonance Imaging; Motion Perception; Retina; Male; Female
PubMed: 38789988
DOI: 10.1186/s12993-024-00239-w -
Journal of Vision May 2024In previous studies, we found that tracking multiple objects involves anticipatory attention, especially in the linear direction, even when a target bounced against a...
In previous studies, we found that tracking multiple objects involves anticipatory attention, especially in the linear direction, even when a target bounced against a wall. We also showed that active involvement, in which the wall was replaced by a controllable paddle, resulted in increased allocation of attention to the bounce direction. In the current experiments, we wanted to further investigate the potential influence of the valence of the heading of an object. In Experiments 1 and 2, participants were instructed to catch targets with a movable goal. In Experiment 3, participants were instructed to manipulate the permeability of a static wall in order to let targets either approach goals (i.e., green goals) or avoid goals (i.e., red goals). The results of Experiment 1 showed that probe detection ahead of a target that moved in the direction of the goal was higher as compared to probe detection in the direction of a no-goal area. Experiment 2 provided further evidence that the attentional highlighting found in the first experiment depends on the movement direction toward the goal. In Experiment 3, we found that not so much the positive (or neutral) valence (here, the green and no-goal areas) led to increased allocation of attention but rather a negative valence (here the red goals) led to a decreased allocation of attention.
Topics: Humans; Attention; Female; Male; Young Adult; Adult; Goals; Motion Perception; Photic Stimulation; Anticipation, Psychological
PubMed: 38787571
DOI: 10.1167/jov.24.5.10 -
Journal of Vision May 2024Contextual modulation occurs for many aspects of high-level vision but is relatively unexplored for the perception of walking direction. In a recent study, we observed...
Contextual modulation occurs for many aspects of high-level vision but is relatively unexplored for the perception of walking direction. In a recent study, we observed an effect of the temporal context on perceived walking direction. Here, we examined the spatial contextual modulation by measuring the perceived direction of a target point-light walker in the presence of two flanker walkers, one on each side. Experiment 1 followed a within-subjects design. Participants (n = 30) completed a spatial context task by judging the walking direction of the target in 13 different conditions: a walker alone in the center or with two flanking walkers either intact or scrambled at a flanker deviation of ±15°, ±30°, or ±45°. For comparison, participants completed an adaptation task where they reported the walking direction of a target after adaptation to ±30° walking direction. We found the expected repulsive effects in the adaptation task but attractive effects in the spatial context task. In Experiment 2 (n = 40), we measured the tuning of spatial contextual modulation across a wide range of flanker deviation magnitudes ranging from 15° to 165° in 15° intervals. Our results showed significant attractive effects across a wide range of flanker walking directions with the peak effect at around 30°. The assimilative versus repulsive effects of spatial contextual modulation and temporal adaptation suggest dissociable neural mechanisms, but they may operate on the same population of sensory channels coding for walking direction, as evidenced by similarity in the peak tuning across the walking direction of the inducers.
Topics: Humans; Walking; Male; Female; Adult; Young Adult; Space Perception; Motion Perception; Photic Stimulation; Adaptation, Physiological
PubMed: 38787570
DOI: 10.1167/jov.24.5.11