Age-related Electrophysical Correlates of Cross-modal Attention Switching.

The human experience demands seamless attentional switches between sensory modalities. Aging raises questions about how declines in auditory and visual processing affect cross-modal attention switching. This study used a cued cross-modal attention-switching paradigm where visual and auditory stimuli were simultaneously presented on either spatially congruent or incongruent sides. A modality cue indicated the target modality, requiring a spatially left versus right key-press response. EEG recordings were collected during task performance. We investigated whether the mixing costs (decreased performance for repetition trials in a mixed task compared with a single task) and switch costs (decreased performance for a switch of target modality compared with a repetition) in cross-modal attention-switching paradigms would exhibit similarities in terms of behavioral performance and the ERP components to those observed in the traditional unimodal attention-switching paradigms. Specifically, we focused on the ERP components: cue-locked P3 (mixing/switch-related increased positivity), target-locked P3 (mixing/switch-related decreased positivity), and target-locked lateralized readiness potential (mixing/switch-related longer latency). In addition, we assessed how aging impacts cross-modal attention-switching performance. Results revealed that older adults exhibited more pronounced mixing and switch costs than younger adults, especially when visual and auditory stimuli were presented on incongruent sides. ERP findings showed increased cue-locked P3 amplitude, prolonged cue-locked P3 latency, decreased target-locked P3 amplitude, prolonged target-locked P3 latency in association with switch costs, and prolonged onset latency of the target-locked lateralized readiness potential in association with the mixing costs. Age-related effects were significant only for cue-locked P3 amplitude, cue-locked P3 latency (switch-related), and target-locked P3 latency (switch-related). These findings suggest that the larger mixing costs and switch costs in older adults were because of the inefficient use of modality cues to update a representation of the relevant task sets and required more processing time for evaluating and categorizing the target.

Impact of aging on crossmodal attention switching.

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.

Temporal synchrony discrimination is abnormal in dichoptic but not monocular visual processing in treated anisometropic amblyopes.

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.

A comparison of pedestal effects in first- and second-order patterns.

The human visual system is sensitive to both luminance (first-order) and contrast (second-order) modulations in an image. A linear-nonlinear-linear model is commonly used to explain visual processing of second-order patterns. Here we used a pattern-masking paradigm to compare first-order and second-order visual mechanisms and to characterize the nonlinear properties underlying them. The carriers were either a high-frequency horizontal grating (8 c/°) or a binary random dot pattern; they were either added to a vertical low-frequency (2 c/°) sinusoidal grating (first-order stimuli) or multiplied by it (second-order stimuli). The incremental discrimination threshold of the target was measured with pedestals whose spatial properties matched those of the target, with the exception of contrast (in the first-order pedestal) or modulation depth (in the second-order pedestal). The threshold function showed a typical dipper shape for both first- and second-order stimuli. The results for the first-order stimuli with different types of carrier and the second-order stimuli with a grating carrier were well explained by a divisive inhibition model in which the facilitatory input was divided by the sum of broadband inhibitory inputs. The results for the second-order stimuli with a random-dot carrier were explained by a modified divisive inhibition model that operated on modulation depth. Our results suggest that divisive inhibition is required to explain visual discrimination in both first- and second-order patterns. However, the source and nonlinearity of the divisive inhibition may be different for these two types of patterns and carrier.

Drawing as a window to emotion with insights from tech-transformed participant images.

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.

Interocular suppression in amblyopia for global orientation processing.

We developed a dichoptic global orientation coherence paradigm to quantify interocular suppression in amblyopia. This task is biased towards ventral processing and allows comparison with two other techniques-global motion processing, which is more dorsally biased, and binocular phase combination, which most likely reflects striate function. We found a similar pattern for the relationship between coherence threshold and interocular contrast curves (thresholds vs. interocular contrast ratios or TvRs) in our new paradigm compared with those of the previous dichoptic global motion coherence paradigm. The effective contrast ratios at balance point (where the signals from the two eyes have equal weighting) in our new paradigm were larger than those of the dichoptic global motion coherence paradigm but less than those of the binocular phase combination paradigm. The measured effective contrast ratios in the three paradigms were also positively correlated with each other, with the two global coherence paradigms having the highest correlation. We concluded that: (a) The dichoptic global orientation coherence paradigm is effective in quantifying interocular suppression in amblyopia; and (b) Interocular suppression, while sharing a common suppression mechanism at the early stage in the pathway (e.g., striate cortex), may have additional extra-striate contributions that affect both dorsal and ventral streams differentially.

Examining the automaticity and symmetry of sound-shape correspondences.

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.

Food supplement 20070721-GX may increase CD34+ stem cells and telomerase activity.

Few rejuvenation and antiaging markers are used to evaluate food supplements. We measured three markers in peripheral blood to evaluate the antiaging effects of a food supplement containing placental extract. Samples were evaluated for CD34(+) cells, insulin-like growth factor 1 (IGF1), and telomerase activity, which are all markers related to aging. To control the quality of this food supplement, five active components were monitored. In total, we examined 44 individuals who took the food supplement from 1.2 months to 23 months; the average number of CD34(+) cells was almost 6-fold higher in the experimental group compared with the control group. Food supplement intake did not change serum IGF1 levels significantly. Finally, the average telomerase activity was 30% higher in the subjects taking this food supplement. In summary, our results suggest that the placental extract in the food supplement might contribute to rejuvenation and antiaging.

Interocular suppression in normal and amblyopic vision: spatio-temporal properties.

We measured the properties of interocular suppression in strabismic amblyopes and compared these to dichoptic masking in binocularly normal observers. We used a dichoptic version of the well-established probed-sinewave paradigm that measured sensitivity to a brief target stimulus (one of four letters to be discriminated) in the amblyopic eye at different times relative to a suppression-inducing mask in the fixing eye. This was done using both sinusoidal steady state and transient approaches. The suppression-inducing masks were either modulations of luminance or contrast (full field, just overlaying the target, or just surrounding the target). Our results were interpreted using a descriptive model that included contrast gain control and spatio-temporal filtering prior to excitatory binocular combination. The suppression we measured, other than in magnitude, was not fundamentally different from normal dichoptic masking: lowpass spatio-temporal properties with similar contributions from both surround and overlay suppression.

Orientation coherence sensitivity.

We developed a global orientation coherence task for the assessment of global form processing along similar lines to the global motion coherence task. The task involved judgments of global orientation for an array of limited duration 1-D Gabors, some of which were signal (signal orientation) and some of which were noise (random orientation). We address two issues. First: Do motion and form global processing have similar dependencies? And second: Can global sensitivity be explained solely in terms of integrative function? While most dependencies (e.g., contrast, spatial scale, and field size) are similar for form and motion processing, there is a greater dependence on eccentricity for form processing. Sensitivity for global tasks involves more than just integration by filters broadly tuned for orientation. Results are best modeled by filters with narrowband orientation tuning that effectively segregate as well as integrate global information.

Collinear facilitation over space and depth.

The detection threshold of a Gabor target can be reduced by the presence of collinear flanking Gabors but is disrupted when the target and the flankers have different disparity. Here, we further investigated whether it is the depth or surface difference between the target and the flanker that causes the abolition of collinear facilitation. The target and the flankers were 1.6 cycle per degree vertical Gabor patches with a separation of three wavelength units between them. There were six viewing conditions: target and flankers were set (A) in the same frontoparallel plane in a collinear configuration, (B) at different disparities but embedded in the same slanted plane, (C) at different disparities in different frontoparallel planes (flankers occupied at the same depth), (D) at different disparities in different frontoparallel planes (flankers occupied at different depth), (E) in the same frontoparallel plane in a noncollinear configuration, and (F) at the same disparity but locally slanted. We measured the target contrast detection threshold with and without the flankers present with a temporal 2AFC paradigm with the Ψ staircase method. Strong collinear facilitation was observed when the target and the flankers were either in the same frontoparallel plane or embedded in the same slanted surface even though the target and the flankers were at different disparities. Our results suggest that it is the difference in surface assignment, not the difference in disparity per se, that causes the disruption of collinear facilitation.

Pattern masking: the importance of remote spatial frequencies and their phase alignment.

To assess the effects of spatial frequency and phase alignment of mask components in pattern masking, target threshold vs. mask contrast (TvC) functions for a sine-wave grating (S) target were measured for five types of mask: a sine-wave grating (S), a square-wave grating (Q), a missing fundamental square-wave grating (M), harmonic complexes consisting of phase-scrambled harmonics of a square wave (Qp), and harmonic complexes consisting of phase-scrambled harmonics of a missing fundamental square wave (Mp). Target and masks had the same fundamental frequency (0.46 cpd) and the target was added in phase with the fundamental frequency component of the mask. Under monocular viewing conditions, the strength of masking depends on phase relationships among mask spatial frequencies far removed from that of the target, at least 3 times the target frequency, only when there are common target and mask spatial frequencies. Under dichoptic viewing conditions, S and Q masks produced similar masking to each other and the phase-scrambled masks (Qp and Mp) produced less masking. The results suggest that pattern masking is spatial frequency broadband in nature and sensitive to the phase alignments of spatial components.

Seeing Sounds: The Role of Vowels and Consonants in Crossmodal Correspondences.

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.

A Joint Lateral Motion-Stereo Constraint.

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.

Intracerebral transplantation of autologous adipose-derived stem cells for chronic ischemic stroke: A phase I study.

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.

Butylidenephthalide suppresses human telomerase reverse transcriptase (TERT) in human glioblastomas.

BACKGROUND: Telomerase is widely expressed in most human cancers, but is almost undetectable in normal somatic cells and is therefore a potential drug target. Using the human telomerase promoter platform, the naturally occurring compound butylidenephthalide (BP) was selected for subsequent investigation of antitumor activity in vitro and in vivo. METHODS: We treated human glioblastoma cells with BP and found a dose-dependent decrease in human telomerase reverse transcriptase (hTERT) mRNA expression and a concomitant increase in p16 and p21 expression. Because c-Myc and Sp1 are involved in transcriptional regulation of hTERT, the effect of BP on c-Myc and Sp1 expression was examined. RESULTS: Using electrophoretic mobility shift assays and western blotting, we showed that BP represses hTERT transcriptional activity via downregulation of Sp1 expression. Using the telomerase repeat amplification protocol, an association between BP concentration and suppression of telomerase activity, induction of human glioblastoma senescence, and inhibition of cellular proliferation was identified. This was supported by a mouse xenograft model, in which BP repressed telomerase and inhibited tumor proliferation, resulting in tumor senescence. Overexpression of hTERT restored telomerase activity in human glioblastoma cells and overcame replicative senescence. CONCLUSIONS: These findings suggest that BP inhibits proliferation and induces senescence in human glioblastomas by downregulating hTERT expression and consequently telomerase activity. This is the first study to describe regulation of telomerase activity by BP in human glioblastomas.

Stimulus temporal uncertainty balances intersensory dominance.

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.

Global shape perception contributes to crossmodal correspondences.

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).

The Effects of Mandarin Chinese Lexical Tones in Sound-Shape and Sound-Size Correspondences.

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.

The effects of flankers on contrast detection and discrimination in binocular, monocular, and dichoptic presentations.

We investigated how two co-aligned adjacent stimuli (flankers) influence threshold versus pedestal contrast (TvC) functions in binocular, monocular, and dichoptic presentations. Targets were presented to the two eyes or to only one eye. Pedestals and flankers were presented to the same eye to which the target was presented (binocular or monocular presentations) or to the other eye (dichoptic presentation). In the binocular presentation of targets and pedestals, the binocular flankers lowered thresholds at low pedestal contrasts. The monocular flankers had a similar effect to the binocular flanker, although the threshold reduction was smaller. In the dichoptic presentation of a target and a pedestal, flankers lowered thresholds when flankers were presented to the eye where targets were presented. In contrast, dichoptic flankers elevated thresholds at intermediate pedestal contrasts when a pedestal was also dichoptically presented. We fitted binocular contrast gain control models to the data. It follows from the fitting results that flankers modulate outputs from spatial filters in the monocular processing stage of contrast gain control.