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1.
Psychol Res ; 2024 Jun 26.
Article in English | MEDLINE | ID: mdl-38922395

ABSTRACT

Previous studies on crossmodal visual-auditory attention switching using a spatial discrimination task showed performance costs when the target modality changed relative to when it repeated. The present study (n = 42 for each age group) examined age-related changes in crossmodal attention switching by asking young (age range 19 to 30 years old) and older (age range 64 to 80 years old) participants to respond to unimodal central cues and bimodal lateralized stimuli. The participants' task was to indicate the location of the target in the relevant modality using button presses. Results showed general attention switch costs. Additionally, we found no specific age-related increase of attention switch costs (no difference in performance between switch and repetition of target modality), but age-related increased mixing costs (decreased performance for repetition in modality-mixed condition compared to single target modality). Moreover, spatial distraction produced a crossmodal congruency effect, which was only slightly larger in older adults. Taken together, age-related increased mixing costs suggest a general difficulty with maintaining more than one task, but no specific age-related crossmodal impairment in crossmodal attention switching.

2.
Sci Rep ; 14(1): 11571, 2024 05 21.
Article in English | MEDLINE | ID: mdl-38773125

ABSTRACT

This study delves into expressing primary emotions anger, happiness, sadness, and fear through drawings. Moving beyond the well-researched color-emotion link, it explores under-examined aspects like spatial concepts and drawing styles. Employing Python and OpenCV for objective analysis, we make a breakthrough by converting subjective perceptions into measurable data through 728 digital images from 182 university students. For the prominent color chosen for each emotion, the majority of participants chose red for anger (73.11%), yellow for happiness (17.8%), blue for sadness (51.1%), and black for fear (40.7%). Happiness led with the highest saturation (68.52%) and brightness (75.44%) percentages, while fear recorded the lowest in both categories (47.33% saturation, 48.78% brightness). Fear, however, topped in color fill percentage (35.49%), with happiness at the lowest (25.14%). Tangible imagery prevailed (71.43-83.52%), with abstract styles peaking in fear representations (28.57%). Facial expressions were a common element (41.76-49.45%). The study achieved an 81.3% predictive accuracy for anger, higher than the 71.3% overall average. Future research can build on these results by improving technological methods to quantify more aspects of drawing content. Investigating a more comprehensive array of emotions and examining factors influencing emotional drawing styles will further our understanding of visual-emotional communication.


Subject(s)
Emotions , Facial Expression , Humans , Emotions/physiology , Male , Female , Young Adult , Happiness , Anger/physiology , Adult , Fear/psychology , Sadness
3.
Front Psychol ; 14: 1172946, 2023.
Article in English | MEDLINE | ID: mdl-37342641

ABSTRACT

Introduction: A classic example of sound-shape correspondences is the mapping of the vowel /i/ with angular patterns and the vowel /u/ with rounded patterns. Such crossmodal correspondences have been reliably reported when tested in explicit matching tasks. Nevertheless, it remains unclear whether such sound-shape correspondences automatically occur and bidirectionally modulate people's perception. We address this question by adopting the explicit matching task and two implicit tasks. Methods: In Experiment 1, we examined the sound-shape correspondences using the implicit association test (IAT), in which the sounds and shapes were both task-relevant, followed by an explicit matching task. In Experiments 2 and 3, we adopted the speeded classification task; when the target was a sound (or shape), a task-irrelevant shape (or sound) that was congruent or incongruent to the target was simultaneously presented. In addition, the participants performed the explicit matching task either before or after the speeded classification task. Results and Discussion: The congruency effect was more pronounced in the IAT than in the speeded classification task; in addition, a bin analysis of RTs revealed that the congruency effect took time to develop. These findings suggest that the sound-shape correspondences were not completely automatic. The magnitude and onset of visual and auditory congruency effects were comparable, suggesting that the crossmodal modulations were symmetrical. Taken together, the sound-shape correspondences appeared not to be completely automatic, but their modulation was bidirectionally symmetrical once it occurred.

4.
Ophthalmic Physiol Opt ; 43(2): 263-272, 2023 03.
Article in English | MEDLINE | ID: mdl-36648010

ABSTRACT

PURPOSE: To evaluate whether temporal synchrony processing deficits remain when normal visual acuity is restored in adults with unilateral anisometropic amblyopia. METHODS: We recruited 14 clinically treated anisometropic amblyopes (mean age 23.17 ± 2.53 years) with best-corrected visual acuity ≤ 0.1 logMAR and 15 age-matched emmetropes (mean age 24.40 ± 1.92 years) with normal vision to participate in our experiment. We presented two pairs of flicking Gaussian dots (1 Hz) as visual stimuli: one pair of dots was synchronous (reference), and the other pair of dots was asynchronous (signal). Subjects were asked to determine the position of the asynchronous pair. We applied the constant stimuli method to measure the temporal synchrony threshold under monocular and dichoptic viewing conditions. There were eight temporal phase lags in the asynchronous pair. The minimum degree of the temporal phase at which a participant can discriminate a signal pair is defined as the temporal synchrony threshold. RESULTS: Under monocular viewing conditions where both the reference and signal pairs were presented to one eye, the temporal synchrony thresholds of previous amblyopic eyes and fellow eyes were not significantly different (p = 0.15). Under dichoptic viewing conditions where both the reference and signal pairs were dichoptically presented to both eyes, the temporal synchrony threshold in the treated anisometropic amblyopes was significantly higher than that of the controls (119.34 ± 20.43 vs. 99.78 ± 16.60 ms, p = 0.009). There was no significant correlation between the monocular and dichoptic viewing conditions in the treated amblyopes (r = -0.22, p = 0.94). CONCLUSIONS: Temporal synchrony discrimination is abnormal under dichoptic but not under monocular visual stimulation in treated anisometropic amblyopes with normalised visual acuity.


Subject(s)
Amblyopia , Adult , Humans , Young Adult , Amblyopia/diagnosis , Amblyopia/therapy , Vision, Binocular/physiology , Visual Perception , Visual Acuity , Eye
5.
Iperception ; 13(2): 20416695221084724, 2022.
Article in English | MEDLINE | ID: mdl-35321530

ABSTRACT

Crossmodal correspondences refer to the fact that certain domains of features in different sensory modalities are associated with each other. Here, we investigated the crossmodal correspondences between speech sounds and visual shapes. Specifically, we tested whether the classification dimensions of English vowels (front-central-back) and consonants (voiced-voiceless, sonorant-obstruent, and stop-continuant) correspond to visual shapes along a bipolar rounded-angular dimension. We adapted eighteen meaningless pseudowords from a previous study that corresponded to either the round or the sharp concept. On each trial, the participants heard one of the pseudowords and saw a rounded shape and an angular shape presented side-by-side on the monitor. Participants judged which shape provided a better match to the spoken pseudoword. A logistic regression was conducted in order to elucidate the effectiveness of classification dimensions of phonemes when predicting variations in the sound-shape matchings. The results demonstrated that the sound-shape matchings were predictable using front-central-back dimensions of vowels, and voiced-voiceless and stop-continuant dimensions of consonants. Hence, we verified that sound-shape matching is underpinned by contrasting dimensions in both vowels and consonants, therefore demonstrating crossmodal correspondences at the phonetic level.

6.
Invest Ophthalmol Vis Sci ; 63(1): 32, 2022 01 03.
Article in English | MEDLINE | ID: mdl-35077551

ABSTRACT

Purpose: We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction. Methods: In this study, we quantified normal adults' static and dynamic (i.e., laterally moving) stereoscopic performance using a psychophysical task, where we dichoptically presented randomly arranged, limited lifetime Gabor elements at two depth planes (one plane was at the fixation plane and the other at an uncrossed disparity relative to the fixation plane). Each plane contained half of the elements. For the dynamic condition, all elements were vertically oriented and moved to the left in one plane and to the right in another plane; for the static condition, the elements were horizontally oriented in one plane and vertically oriented in another plane. Results: For the range of motion speed that we measured (from 0.17°/s to 5.33°/s), we observed clear speed tuning of the stereo sensitivity (P = 3.0 × 10-5). The shape of this tuning did not significantly change with different spatial frequencies. We also found a significant difference in stereo sensitivity between stereopsis with static and laterally moving stimuli (speed = 0.67°/s; P = 0.004). Such difference was not evident when we matched the task between the static and moving stimuli. Conclusions: We report that lateral motion modulates human global depth perception. This motion/stereo constraint is related to motion velocity not stimulus temporal frequency. We speculate that the processing of motion-based stereopsis of the kind reported here occurs in dorsal extrastriate cortex.


Subject(s)
Depth Perception/physiology , Motion Perception/physiology , Psychophysics/methods , Vision Disparity/physiology , Vision, Binocular , Visual Cortex/physiology , Adult , Female , Humans , Male , Reference Values , Young Adult
7.
J Tissue Eng Regen Med ; 16(1): 3-13, 2022 01.
Article in English | MEDLINE | ID: mdl-34644444

ABSTRACT

Current therapy does not provide significant benefits for patients with chronic stroke. Pre-clinical studies suggested that autologous adipose-derived stem cells have benefits for the treatment of chronic stroke. This Phase I open-label study was conducted to demonstrate the safety and efficacy of autologous adipose-derived stem cells (GXNPC1) in chronic stroke. Three patients with chronic stroke were treated with stereotactic implantation of autologous adipose-derived stem cells (1 × 108 cells). The primary endpoints of safety evaluation included adverse events, over a 6 months post-implantation period. The secondary endpoints included improvements in neurological functions. Evolutional change of brain parenchyma was also followed with magnetic resonance imaging (MRI). All three participants improved significantly at 6 months follow-up. The extent of improvement from pre-treatment was: National Institutes of Health Stroke Scale improved 5-15 points, Barthel Index: 25-50 points, Berg balance scale 0-21 points and Fugl-Meyer modified sensation 3-28 points. All three patients had signal change along the implantation tract on MRI one month after surgery. There is no related safety issue through 6 months observation. Clinical measures of neurological symptoms of these patients with chronic stroke improved at 6 months without adverse effects after implantation of autologous adipose-derived stem cells (GXNPC1), which might be correlated with post-implantation changes on brain MRI. Clinical Trial Registration-URL: https://clinicaltrials.gov/ct2/show/NCT02813512?term=ADSC&cond=Stroke&cntry=TW&draw=2&rank=1 Unique identifier: NCT02813512.


Subject(s)
Ischemic Stroke , Mesenchymal Stem Cell Transplantation , Stroke , Adipose Tissue , Humans , Mesenchymal Stem Cell Transplantation/methods , Stroke/therapy , Transplantation, Autologous , Treatment Outcome
8.
Psychon Bull Rev ; 28(6): 1874-1884, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34159527

ABSTRACT

Vision is typically dominant over audition or touch in human adults. One classic example is the Colavita visual dominance effect: The presentation of a tone sometimes goes undetected when it is paired with a flash even though it is well detected when presented alone. We investigated whether the Colavita visual dominance effect is modulated by stimulus uncertainty in the temporal and spatial domains. In a simple discrimination task, participants were asked to press a predesignated key when detecting a flash, another key when detecting a tone, and both keys when detecting both a flash and a tone. Temporal uncertainty was increased by introducing temporal jitter between trials (Experiment 1), and spatial uncertainty was increased by shifting the flash to different locations (Experiment 2). The Colavita visual dominance effect was reduced when temporal uncertainty was increased, while it remained similar when spatial uncertainty was increased. We therefore demonstrate a novel consideration, where increasing temporal uncertainty balances the competition between vision and audition, suggesting that people's degree of sensory dominance is malleable. Our result therefore highlights the concept that intersensory competition is susceptible to the temporal predictability of the stimulus, which provides critical insights into the design of effective warning systems in the field of ergonomics.


Subject(s)
Auditory Perception , Visual Perception , Acoustic Stimulation , Adult , Humans , Photic Stimulation , Reaction Time , Uncertainty
9.
J Exp Psychol Hum Percept Perform ; 47(3): 357-371, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33492162

ABSTRACT

The Bouba/Kiki effect constitutes a classic sound-shape correspondence, with the meaningless sounds "Bouba" and "Kiki" being mapped onto smooth and spiky patterns, respectively. While it is commonly believed that the Bouba/Kiki effect is driven by the local rounded and angular features of a pattern, here we investigated the importance of an alternative level of visual processing-namely the global contours. We adopted compound radial frequency (RF) patterns and segmented them into convexities (outward curves) or concavities (inward curves). Note that convexities are more informative in terms of inferring the global contour than concavities. When the perceptual grouping of segments was facilitated by increasing their length, the grouping of convexities was more efficient than that of concavities as manifested by the closer matching judgments to the compound RF patterns. When we interfered with the perceptual grouping of segments by rotating each segment by 180°, the matching consensus of convexities was higher when they were presented in the original than in the reversed orientation. Hence, the Bouba/Kiki effect was susceptible to the factors modulating the perceptual grouping process going from segments to the global contour, suggesting that the Bouba/Kiki effect may occur at the global level of shape perception. Sound-shape correspondences would therefore seem to be expressed at multiple levels of information processing, furthering our understanding of the development, underpinning neural mechanisms, and applications of crossmodal correspondences. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Subject(s)
Form Perception , Visual Perception , Cognition , Humans , Sound
10.
Multisens Res ; 35(3): 243-257, 2021 12 30.
Article in English | MEDLINE | ID: mdl-35065537

ABSTRACT

Crossmodal correspondences refer to when specific domains of features in different sensory modalities are mapped. We investigated how vowels and lexical tones drive sound-shape (rounded or angular) and sound-size (large or small) mappings among native Mandarin Chinese speakers. We used three vowels (/i/, /u/, and /a/), and each vowel was articulated in four lexical tones. In the sound-shape matching, the tendency to match the rounded shape was decreased in the following order: /u/, /i/, and /a/. Tone 2 was more likely to be matched to the rounded pattern, whereas Tone 4 was more likely to be matched to the angular pattern. In the sound-size matching, /a/ was matched to the larger object more than /u/ and /i/, and Tone 2 and Tone 4 correspond to the large-small contrast. The results demonstrated that both vowels and tones play prominent roles in crossmodal correspondences, and sound-shape and sound-size mappings are heterogeneous phenomena.


Subject(s)
Speech Perception , China , Humans , Sound
11.
Invest Ophthalmol Vis Sci ; 61(8): 1, 2020 07 01.
Article in English | MEDLINE | ID: mdl-32609295

ABSTRACT

Purpose: The purpose of this study was to present our investigation of the influence of reduced monocular luminance on monocular and dichoptic temporal synchrony processing in healthy adults. Methods: Ten adults with normal or corrected to normal visual acuity participated in our psychophysical study. The temporal synchrony threshold in dichoptic (experiment 1), monocular (experiment 2), and binocular (experiment 3) viewing configurations was obtained from each observer. Four flickering Gaussian dots (one synchronous and one asynchronous pair of two dots) were displayed, from which the observers were asked to identify the asynchronous pair. The temporal phase lag in the signal pair (asynchronous) but not in the reference pair (synchronous) was varied. In addition, a neutral density (ND) filter of various intensities (1.3 and 2.0 log units) was placed before the dominant eye throughout the behavioral measurement. In the end, dichoptic, monocular, and binocular thresholds were measured for each observer. Results: With decreasing monocular luminance, the dichoptic threshold (2 ND vs. 0 ND, P < 0.001; 2 ND vs. 1.3 ND P = 0.001) and monocular threshold (2 ND vs. 0 ND, P < 0.001; 2 ND vs. 1.3 ND, P = 0.003) increased; however, the bincoular threshold remained unaffected (P = 0.576). Conclusions: Reduced luminance induces delay and disturbs the discrimination of temporal synchrony. Our findings have clinical implications in visual disorders.


Subject(s)
Contrast Sensitivity/physiology , Evoked Potentials, Visual/physiology , Sensory Thresholds/physiology , Temporal Lobe/physiology , Vision, Monocular/physiology , Adult , Female , Humans , Male , Photic Stimulation , Psychophysics , Reference Values
12.
Front Neurosci ; 14: 402, 2020.
Article in English | MEDLINE | ID: mdl-32410957

ABSTRACT

Studies on binocular combination and rivalry show that short-term deprivation strengthens the contribution of the deprived eye in binocular vision. However, whether short-term monocular deprivation affects temporal processing per se is not clear. To address this issue, we conducted a study to investigate the effect of monocular deprivation on dichoptic temporal synchrony. We tested ten adults with normal vision and patched their dominant eye with an opaque patch for 2.5 h. A temporal synchrony paradigm was used to measure if temporal synchrony thresholds change as a result of monocular pattern deprivation. In this paradigm, we displayed two pairs of Gaussian blobs flickering at 1 Hz with either the same or different phased- temporal modulation. In Experiment 1, we obtained the thresholds for detecting temporal asynchrony under dichoptic viewing configurations. We compared the thresholds for temporal synchrony between before and after monocular deprivation and found no significant changes of the interocular synchrony. In Experiment 2, we measured the monocular thresholds for detecting temporal asynchrony. We also found no significant changes of the monocular synchrony of either the patched eye or the unpatched eye. Our findings suggest that short-term monocular deprivation induced-plasticity does not influence monocular or dichoptic temporal synchrony at low temporal frequency.

13.
Cell Transplant ; 28(1_suppl): 100S-111S, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31722556

ABSTRACT

Currently, the only effective therapy for cirrhosis of the liver is liver transplantation. However, finding a compatible liver is difficult due to the low supply of healthy livers and the ever-increasing demand. However, stem-cell therapy may offer a solution for liver cirrhosis; for example, GXHPC1 therapy preparation contains adipose-derived mesenchymal stem cells (AD-MSCs) and was developed for the treatment of liver cirrhosis. In our previous report, animal studies suggested that treatment of a diseased liver via GXHPC1 transplantation can abrogate liver fibrosis and facilitate recovery of liver function. In our current human trial, patients with liver cirrhosis were included. Their adipose tissue was harvested from the subcutaneous fat of the abdominal wall during surgery. AD-MSCs were cultured and suspended at a concentration of 100 million cells in 1 ml of physiological saline (i.e., GXHPC1). This human study passed the Taiwan Food and Drug Administration IND inspection and received Phase I clinical trial permission. The trial was conducted with six patients with liver cirrhosis to demonstrate the safety and efficacy of administering GXHPC1. Intrahepatic injection of GXHPC1 did not cause any safety issues in the analysis of adverse drug reactions and suspected unexpected serious adverse reactions, and showed a tendency for improvement of liver function, METAVIR score, Child-Pugh score, MELD score, and quality of life for patients with liver cirrhosis.


Subject(s)
Adipose Tissue/cytology , Liver Cirrhosis/therapy , Mesenchymal Stem Cell Transplantation/methods , Adipose Tissue/surgery , Adult , Cell Survival , Cells, Cultured , Cytokines/metabolism , Female , Humans , Liver Cirrhosis/blood , Liver Cirrhosis/pathology , Male , Mesenchymal Stem Cell Transplantation/adverse effects , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/metabolism , Middle Aged , Quality of Life , Transplantation, Autologous/adverse effects , Transplantation, Autologous/methods
14.
Invest Ophthalmol Vis Sci ; 60(14): 4858-4864, 2019 11 01.
Article in English | MEDLINE | ID: mdl-31747686

ABSTRACT

Purpose: We investigate temporal synchrony within one eye and between both eyes in adults with amblyopia. Methods: Eight adult amblyopes (range, 19.88-27.81 years old; median, 22.86 years old) and 12 age-matched adults with normal vision (range, 21.2-50.30 years old; median, 23.78 years old) participated in the experiment. We showed two pairs of Gaussian blobs flickering at 1 Hz as visual stimuli, one pair with the same temporal phase modulation (i.e., the reference) and another pair with a distinct temporal phase (i.e., the signal). We employed the constant stimuli method to measure the minimum degree of temporal phase (temporal synchrony threshold), at which participants were able to discriminate the signal pair under binocular, monocular, and dichoptic viewing configurations. Results: The temporal synchrony threshold was different across the six configurations (P = 0.001). There was also an interaction between the configuration and the group (P = 0.004). The synchrony threshold was significantly higher in amblyopes than in controls under the configurations where two pairs of blobs were presented to the amblyopic eye (136.52 ± 50.19 vs. 97.08 ± 22.02 ms, P = 0.027) and where the paired blobs were presented to different eyes (163.15 ± 80.85 vs. 111.61 ± 22.46 ms, P = 0.049). The visual deficits in these two configurations were significantly correlated (r = 0.824, P = 0.012). Conclusions: The threshold for detecting temporal asynchrony increased when the stimuli were presented only to the amblyopic eye and when they were dichoptically presented to the amblyopic and fellow eyes.


Subject(s)
Amblyopia/physiopathology , Perceptual Disorders/physiopathology , Sensory Thresholds/physiology , Vision, Binocular/physiology , Adult , Female , Humans , Male , Middle Aged , Motion Perception/physiology , Space Perception/physiology , Spatio-Temporal Analysis , Vision, Monocular/physiology , Visual Acuity/physiology , Young Adult
15.
Psychon Bull Rev ; 26(1): 261-268, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30097975

ABSTRACT

We examined the ability of people to evaluate their confidence when making perceptual judgments concerning a classic crossmodal correspondence, the Bouba/Kiki effect: People typically match the "Bouba" sound to more rounded patterns and match the "Kiki" sound to more angular patterns instead. For each visual pattern, individual participants were more confident about their own matching judgments when they happened to fall in line with the consensual response regarding whether the pattern was rated as "Bouba" or "Kiki". Logit regression analyses demonstrated that participants' confidence ratings and matching judgments were predictable by similar regression functions. This implies that the consensus and confidence underlying the Bouba/Kiki effect are underpinned by a common process, whereby perceptual features in the patterns are extracted and then used to match the sound according to rules of crossmodal correspondences. Combining both matching and confidence measures potentially allows one to explore and quantify the strength of associations in human knowledge.


Subject(s)
Auditory Perception , Metacognition , Self Concept , Visual Perception , Adolescent , Adult , Consensus , Female , Humans , Logistic Models , Male , Young Adult
16.
Can J Ophthalmol ; 53(6): 609-613, 2018 12.
Article in English | MEDLINE | ID: mdl-30502986

ABSTRACT

OBJECTIVE: Both genetic and environmental factors are thought to play a role in the pathogenesis of strabismus and subsequent ocular dominance and amblyopia. Our purpose was to compare the characteristics of sensory visual function in 2 adult monozygotic (genetically identical) twins who presented with esotropia at different ages. METHODS: Monocular and binocular visual function was measured in the twins. Contrast sensitivity was used to assess monocular function. Suppressive and stereoscopic measurements were undertaken to assess binocular function. All tests were run using a 2-alternative forced choice psychophysical procedure. Eighteen short tandem repeats (STR) were genotyped across the genome in both twins to determine their exact relationship. RESULTS: Twin 1 (nondominant eye OD) was diagnosed with esotropia at 6 months of age, whereas twin 2 (nondominant eye OS) was diagnosed with esotropia at 5 years of age. They underwent a similar corrective surgical intervention soon after diagnosis to correct their esodeviations. Monocular contrast sensitivity was poorer for twin 1, particularly at intermediate spatial frequencies. In addition, twin 1 demonstrated complete suppression and unmeasurable stereoscopic function (>300 seconds). On the other hand, twin 2 demonstrated fusion, exhibited only mild suppression, and had near-normal (28 seconds) stereoscopic function. All STR alleles were identical in the twins, proving monozygosity. CONCLUSIONS: Sensory measurements of monocular and binocular visual function in these genetically proven monozygotic twins were significantly different, with the earlier onset of esotropia associated with reduced visual function. Twin 2, whose esotropia was diagnosed at the age of 5 years, had near-normal visual function, both monocularly and binocularly. To the best of our knowledge, this represents the first study of a genetically identical sibling pair with strabismus. By eliminating the genetic differences between these patients, we are able to make powerful observations about the effect of environment on visual function in strabismus.


Subject(s)
Diseases in Twins , Strabismus/epidemiology , Twins, Monozygotic , Vision, Binocular/physiology , Vision, Monocular/physiology , Adolescent , Adult , Age Factors , Child , Child, Preschool , Evoked Potentials, Visual , Female , Genetic Testing , Humans , Infant , Infant, Newborn , Strabismus/diagnosis , Strabismus/genetics , Young Adult
17.
Vision Res ; 146-147: 18-31, 2018 05.
Article in English | MEDLINE | ID: mdl-29704536

ABSTRACT

In the context of natural scenes, we applied the pattern-masking paradigm to investigate how image structure and phase alignment affect contrast-gain control in binocular vision. We measured the discrimination thresholds of bandpass-filtered natural-scene images (targets) under various types of pedestals. Our first experiment had four pedestal types: bandpass-filtered pedestals, unfiltered pedestals, notch-filtered pedestals (which enabled removal of the spatial frequency), and misaligned pedestals (which involved rotation of unfiltered pedestals). Our second experiment featured six types of pedestals: bandpass-filtered, unfiltered, and notch-filtered pedestals, and the corresponding phase-scrambled pedestals. The thresholds were compared for monocular, binocular, and dichoptic viewing configurations. The bandpass-filtered pedestal and unfiltered pedestals showed classic dipper shapes; the dipper shapes of the notch-filtered, misaligned, and phase-scrambled pedestals were weak. We adopted a two-stage binocular contrast-gain control model to describe our results. We deduced that the phase-alignment information influenced the contrast-gain control mechanism before the binocular summation stage and that the phase-alignment information and structural misalignment information caused relatively strong divisive inhibition in the monocular and interocular suppression stages. When the pedestals were phase-scrambled, the elimination of the interocular suppression processing was the most convincing explanation of the results. Thus, our results indicated that both phase-alignment information and similar image structures cause strong interocular suppression.


Subject(s)
Contrast Sensitivity/physiology , Vision, Binocular/physiology , Visual Perception/physiology , Humans , Perceptual Masking/physiology , Photic Stimulation , Sensory Thresholds
18.
Atten Percept Psychophys ; 80(3): 738-751, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29260503

ABSTRACT

Despite the rapid growth of research on the crossmodal correspondence between visually presented shapes and basic tastes (e.g., sweet, sour, bitter, and salty), most studies that have been published to date have focused on shape contour (roundness/angularity). Meanwhile, other important features, such as symmetry, as well as the underlying mechanisms of the shape-taste correspondence, have rarely been studied. Over two experiments, we systematically manipulated the symmetry and contours of shapes and measured the influences of these variables on shape-taste correspondences. Furthermore, we investigated a potential underlying mechanism, based on the common affective appraisal of stimuli in different sensory modalities. We replicated the results of previous studies showing that round shapes are associated with sweet taste, whereas angular shapes are associated with sour and bitter tastes. In addition, we demonstrated a novel effect that the symmetry group of a shape influences how it is associated with taste. A significant relationship was observed between the taste and appraisal scores of the shapes, suggesting that the affective factors of pleasantness and threat underlie the shape-taste correspondence. These results were consistent across cultures, when we compared participants from Taiwanese and Western (UK, US, Canada) cultures. Our findings highlight that perceived pleasantness and threat are culturally common factors involved in at least some crossmodal correspondences.


Subject(s)
Form Perception/physiology , Taste Perception/physiology , Canada , Culture , Emotions , Female , Functional Laterality/physiology , Humans , Male , Taiwan , United Kingdom , United States
19.
PLoS One ; 11(10): e0164171, 2016.
Article in English | MEDLINE | ID: mdl-27764119

ABSTRACT

A plaid is a combination of two gratings whose orientations are orthogonal to each other with the same or similar contrasts. We used plaid patterns as stimuli to investigate the mechanisms underlying the detection of a plaid to understand how the visual system combines information from orientation-selective channels. We used a masking paradigm in which an observer was required to detect a target (either a spiral or a plaid) superimposed on a pedestal. We measured the target threshold versus pedestal contrast (TvC) functions at 7 pedestal contrasts for various target-pedestal combinations with a temporal 2AFC paradigm and a staircase procedure. All TvC functions, except the one with an orthogonal spiral pedestal, showed a dipper shape, although the position of the dip and the slope varied across conditions. The result can be explained by a multiple-mechanism divisive inhibition model, which contains several orientation-selective mechanisms. The response of each mechanism is the excitation of a linear filter divided by a broadband inhibitory input. The threshold is determined by a nonlinear combination of the responses of those mechanisms. Alternative models with mechanism(s) specific for plaid did not provide a better description of the data. Thus, a plaid pattern is mediated by a combination of orientation-selective mechanisms. An early plaid-specific mechanism is not necessary for plaid detection.


Subject(s)
Pattern Recognition, Visual/physiology , Contrast Sensitivity , Humans , Models, Psychological , Photic Stimulation , Sensory Thresholds
20.
Sci Rep ; 6: 26681, 2016 05 27.
Article in English | MEDLINE | ID: mdl-27230754

ABSTRACT

It has been suggested that the Bouba/Kiki effect, in which meaningless speech sounds are systematically mapped onto rounded or angular shapes, reflects a universal crossmodal correspondence between audition and vision. Here, radial frequency (RF) patterns were adapted in order to compare the Bouba/Kiki effect in Eastern and Western participants demonstrating different perceptual styles. Three attributes of the RF patterns were manipulated: The frequency, amplitude, and spikiness of the sinusoidal modulations along the circumference of a circle. By testing participants in the US and Taiwan, both cultural commonalities and differences in sound-shape correspondence were revealed. RF patterns were more likely to be matched with "Kiki" than with "Bouba" when the frequency, amplitude, and spikiness increased. The responses from both groups of participants had a similar weighting on frequency; nevertheless, the North Americans had a higher weighting on amplitude, but a lower weighting on spikiness, than their Taiwanese counterparts. These novel results regarding cultural differences suggest that the Bouba/Kiki effect is partly tuned by differing perceptual experience. In addition, using the RF patterns in the Bouba/Kiki effect provides a "mid-level" linkage between visual and auditory processing, and a future understanding of sound-shape correspondences based on the mechanism of visual pattern processing.


Subject(s)
Language , Sound , Visual Perception/physiology , Adolescent , Adult , Aged , Animals , Humans , Male , Middle Aged
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