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Attention, Perception & Psychophysics May 2023Partial replications of experiments reported by Cai et al. (Attention, Perception, & Psychophysics, 79(4), 1217-1226, 2017) on the so-called Horizontal-vertical illusion...
Partial replications of experiments reported by Cai et al. (Attention, Perception, & Psychophysics, 79(4), 1217-1226, 2017) on the so-called Horizontal-vertical illusion confirmed that dissecting L-figures into two separate lines yields greater overestimation of (near-)verticals than do intact Ls. However, contrary to Cai et al.'s findings, which had been obtained with a staircase procedure, with the method of constant stimuli, the amount of illusion was much smaller. This divergence is explained by the self-reinforcing nature of adjustment procedures. Another finding, already reported by Cormack and Cormack (Perception & Psychophysics, 16(2), 208-212, 1974), that obtuse angles between an L's lines yield greater bias than acute angles, was also replicated in one experiment but tended to be reversed in another. Mixing dissected, upright and top-down inverted Ls and laterally oriented Ts, both with tilted lines, within one experiment confirmed that the bias for Ts is opposite to the one for Ls: For Ts, the effect of (virtual) bisection dominates, yielding an overestimation of the length of the undivided line, whereas for Ls, the horizontal-vertical anisotropy dominates, yielding an overestimation of the length of the vertical line. The differential gap effects can possibly be explained by interactions within the neural substrate between orientation-sensitive and end-inhibited neurons, and the method effects by perceptual learning.
Topics: Humans; Optical Illusions; Orientation; Psychophysics; Discrimination Learning; Learning
PubMed: 37002462
DOI: 10.3758/s13414-023-02696-3 -
Psychonomic Bulletin & Review Oct 2023Physical objects behave following the principle of solidity: One solid object cannot pass through another. To what extent does the visual system integrate this physical...
Physical objects behave following the principle of solidity: One solid object cannot pass through another. To what extent does the visual system integrate this physical regularity as a prior constraint? A new variant of the Pulfrich effect demonstrates a surprising degree of tolerance for violations of solidity when pitted against motion and depth cues. When adult participants view a pendulum swinging in the fronto-parallel plane with both eyes (one of which was covered by a light-attenuating filter), they falsely perceive the pendulum as swinging in an elliptical path (known as the "Pulfrich effect"). Here, we show that even when the pendulum's motion takes place entirely behind a solid horizontal bar, observers nevertheless see the pendulum pass through the bar while moving in an ellipse. This illusion suggests that the Pulfrich effect and the underlying stereoscopic depth cues can be robust to object solidity.
Topics: Adult; Humans; Optical Illusions; Motion Perception; Depth Perception
PubMed: 36964479
DOI: 10.3758/s13423-023-02271-9 -
Attention, Perception & Psychophysics Aug 2023Using a dual-task paradigm, the present investigation examined whether processes related to line orientation play a critical role in the production of the Poggendorff...
Using a dual-task paradigm, the present investigation examined whether processes related to line orientation play a critical role in the production of the Poggendorff illusion. In Experiment 1, we assessed the magnitude of the Poggendorff illusion under three different task conditions. In the single-task condition, participants were asked to report how they perceive the alignment of transversal lines in the Poggendorff figure. In two different dual-task conditions, the participants were asked to read aloud the time displayed on a digital or analogue clock while also performing the Poggendorff perception task. The method of constant stimuli was used to calculate the point of subjective equality (PSE) and bistability width values, which represent illusion strength and perceptual uncertainty, respectively. PSEs indicated that the magnitude of the illusion did not vary between single, dual-analogue, and dual-digital task conditions, which suggests that the additional demands placed by the dual tasks had no effect on the illusion strength. Perceptual uncertainty and clock-reading errors were greater in the dual-analogue task condition. Experiment 2 revealed that the analogue clockface was more difficult to read than the digital clockface. Based on these results, we conclude that having participants perform a secondary task does not influence the magnitude of the Poggendorff illusion.
Topics: Humans; Illusions; Optical Illusions
PubMed: 36949260
DOI: 10.3758/s13414-023-02660-1 -
Brain Communications 2023This study aimed to test our hypothesis that the cerebellum plays an important role in the generation of the optical-geometric illusion known as the Poggendorff...
This study aimed to test our hypothesis that the cerebellum plays an important role in the generation of the optical-geometric illusion known as the Poggendorff illusion, the mechanism of which has been explained by accumulated experience with natural scene geometry. A total of 79 participants, comprising 28 patients with isolated cerebellar stroke, 27 patients with isolated cerebral stroke and 24 healthy controls, performed Poggendorff illusion tasks and 2 different control tasks. We also investigated core brain regions underpinning changes in the experience of the illusion effect using multivariate lesion-symptom mapping. Our results indicate that patients with isolated cerebellar stroke were significantly less likely to experience the Poggendorff illusion effect than patients with isolated cerebral stroke or healthy controls (74.6, 90.5 and 89.8%, respectively; (2,76) = 6.675, = 0.002). However, there were no inter-group differences in the control tasks. Lesion-symptom mapping analysis revealed that the brain lesions associated with the reduced frequency of the Poggendorff illusion effect were mainly centred on the right posteromedial cerebellar region, including the right lobules VI, VII, VIII, IX and Crus II. Our findings demonstrated, for the first time, that patients with cerebellar damage were significantly less likely to experience the Poggendorff illusion effect and that right posteromedial cerebellar lesions played an important role in this effect. These results provide new insight into alterations of a geometric illusion effect in patients with cerebellar disorders and pave the way for future clinical use of the illusion task to detect cerebellar abnormalities.
PubMed: 36938526
DOI: 10.1093/braincomms/fcad053 -
ACS Applied Materials & Interfaces Apr 2023Artificial camouflage has garnered long-standing interest in both academia and industry. The metasurface-based cloak has attracted much attention due to the powerful...
Artificial camouflage has garnered long-standing interest in both academia and industry. The metasurface-based cloak has attracted much attention due to the powerful capability of manipulating the electromagnetic wave, convenient multifunctional integration design, and easy fabrication. However, existing metasurface-based cloaks tend to be passive and of single function and monopolarization, which cannot meet the requirement of applications in ever-changing environments. So far, it is still challenging to realize a reconfigurable full-polarization metasurface cloak with multifunctional integration. Herein, we proposed an innovative metasurface cloak, which can simultaneously realize dynamic illusion effects at lower frequencies (e.g., 4.35 GHz) and specific microwave transparency at higher frequencies (e.g., X band) for communication with the outside environment. These electromagnetic functionalities are demonstrated by both numerical simulations and experimental measurements. The simulation and measurement results agree well with each other, indicating that our metasurface cloak can generate various electromagnetic illusions for full polarizations as well as a polarization-insensitive transparent window for the signal transmission to enable the communication between the cloaked device and the outside environment. It is believed that our design can offer powerful camouflage tactics to address the stealth problem in ever-changing environments.
PubMed: 36867759
DOI: 10.1021/acsami.2c21565 -
Perception Mar 2023Here we present what we believe to be a novel geometric illusion where identical lines are perceived as being of differing lengths. Participants were asked to report...
Here we present what we believe to be a novel geometric illusion where identical lines are perceived as being of differing lengths. Participants were asked to report which of the two parallel rows of horizontal lines contained the longer individual lines (two lines on one row and 15 on the other). Using an adaptive staircase we adjusted the length of the lines on the row containing two to estimate the point of subjective equality (PSE). At the PSE, the two lines were consistently shorter than the row containing the fixed length of 15 lines demonstrating a disparity in perceived length such that lines of identical length are perceived as longer in a row of two than in a row of 15. The illusion magnitude was unaffected by which row was presented above the other. Additionally, the effect persisted when using one as opposed to two test lines, and when the line stimuli on both rows were presented with alternating luminance polarity the illusion magnitude decreased, but was not abolished. The data indicate a robust geometric illusion that may be modulated by perceptual grouping processes.
Topics: Humans; Optical Illusions; Group Processes; Health Status
PubMed: 36794516
DOI: 10.1177/03010066221148437 -
International Journal of Cardiology Apr 2023
Topics: Humans; Coronary Artery Disease; Colchicine; Optical Illusions
PubMed: 36716969
DOI: 10.1016/j.ijcard.2023.01.064 -
Japan Journal of Industrial and Applied... 2023It is widely known among photographers that photographing a room with a wide-angle lens exaggerates the size of the room; nevertheless, such images are commonly found on...
It is widely known among photographers that photographing a room with a wide-angle lens exaggerates the size of the room; nevertheless, such images are commonly found on hotel-reservation web sites. The present paper points out that the size exaggeration is a kind of optical illusion caused by an inappropriate viewpoint from which the image is seen, and presents a method we developed for removing the illusion and thus recovering the true appearance of the room. This method requires only a single image together with the lens center at which the image is taken. From this information, we can generate images that would be obtained if we stand at the same point as the camera and pan around the original scene, changing the view direction. The validity of the method is shown by examples. Possible applications to size-exaggerated images posted on web sites are also discussed.
PubMed: 36685017
DOI: 10.1007/s13160-022-00557-4 -
JAMA Oncology Mar 2023Magnetic resonance imaging (MRI) guidance offers multiple theoretical advantages in the context of stereotactic body radiotherapy (SBRT) for prostate cancer. However, to...
IMPORTANCE
Magnetic resonance imaging (MRI) guidance offers multiple theoretical advantages in the context of stereotactic body radiotherapy (SBRT) for prostate cancer. However, to our knowledge, these advantages have yet to be demonstrated in a randomized clinical trial.
OBJECTIVE
To determine whether aggressive margin reduction with MRI guidance significantly reduces acute grade 2 or greater genitourinary (GU) toxic effects after prostate SBRT compared with computed tomography (CT) guidance.
DESIGN, SETTING, AND PARTICIPANTS
This phase 3 randomized clinical trial (MRI-Guided Stereotactic Body Radiotherapy for Prostate Cancer [MIRAGE]) enrolled men aged 18 years or older who were receiving SBRT for clinically localized prostate adenocarcinoma at a single center between May 5, 2020, and October 1, 2021. Data were analyzed from January 15, 2021, through May 15, 2022. All patients had 3 months or more of follow-up.
INTERVENTIONS
Patients were randomized 1:1 to SBRT with CT guidance (control arm) or MRI guidance. Planning margins of 4 mm (CT arm) and 2 mm (MRI arm) were used to deliver 40 Gy in 5 fractions.
MAIN OUTCOMES AND MEASURES
The primary end point was the incidence of acute (≤90 days after SBRT) grade 2 or greater GU toxic effects (using Common Terminology Criteria for Adverse Events, version 4.03 [CTCAE v4.03]). Secondary outcomes included CTCAE v4.03-based gastrointestinal toxic effects and International Prostate Symptom Score (IPSS)-based and Expanded Prostate Cancer Index Composite-26 (EPIC-26)-based outcomes.
RESULTS
Between May 2020 and October 2021, 156 patients were randomized: 77 to CT (median age, 71 years [IQR, 67-77 years]) and 79 to MRI (median age, 71 years [IQR, 68-75 years]). A prespecified interim futility analysis conducted after 100 patients reached 90 or more days after SBRT was performed October 1, 2021, with the sample size reestimated to 154 patients. Thus, the trial was closed to accrual early. The incidence of acute grade 2 or greater GU toxic effects was significantly lower with MRI vs CT guidance (24.4% [95% CI, 15.4%-35.4%] vs 43.4% [95% CI, 32.1%-55.3%]; P = .01), as was the incidence of acute grade 2 or greater gastrointestinal toxic effects (0.0% [95% CI, 0.0%-4.6%] vs 10.5% [95% CI, 4.7%-19.7%]; P = .003). Magnetic resonance imaging guidance was associated with a significantly smaller percentage of patients with a 15-point or greater increase in IPSS at 1 month (6.8% [5 of 72] vs 19.4% [14 of 74]; P = .01) and a significantly reduced percentage of patients with a clinically significant (≥12-point) decrease in EPIC-26 bowel scores (25.0% [17 of 68] vs 50.0% [34 of 68]; P = .001) at 1 month.
CONCLUSIONS AND RELEVANCE
In this randomized clinical trial, compared with CT-guidance, MRI-guided SBRT significantly reduced both moderate acute physician-scored toxic effects and decrements in patient-reported quality of life. Longer-term follow-up will confirm whether these notable benefits persist.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT04384770.
Topics: Male; Humans; Aged; Prostate; Radiosurgery; Quality of Life; Optical Illusions; Prostatic Neoplasms; Magnetic Resonance Imaging; Tomography, X-Ray Computed
PubMed: 36633877
DOI: 10.1001/jamaoncol.2022.6558 -
JAMA Oncology Mar 2023
Clinical Trial
Topics: Humans; Male; Optical Illusions; Pelvis; Prostate; Prostatic Neoplasms; Radiosurgery; Radiotherapy Dosage
PubMed: 36633862
DOI: 10.1001/jamaoncol.2022.6334