scholarly journals Snakes and ladders: the role of temporal modulation in visual contour integration

2001 ◽  
Vol 41 (27) ◽  
pp. 3775-3782 ◽  
Author(s):  
Peter J Bex ◽  
Anita J Simmers ◽  
Steven C Dakin
Keyword(s):  
Contour Integration ◽  
Temporal Modulation ◽  
Visual Contour

scholarly journals Reduced influence of perceptual context in schizophrenia: behavioral and neurophysiological evidence

2019 ◽  
pp. 1-9 ◽  
Author(s):  
Victor J. Pokorny ◽  
Timothy J. Lano ◽  
Michael-Paul Schallmo ◽  
Cheryl A. Olman ◽  
Scott R. Sponheim
Keyword(s):  
Event Related Potentials ◽  
Contour Integration ◽  
Contour Detection ◽  
Group Differences ◽  
Neural Responses ◽  
Contour Perception ◽  
Accurate Perception ◽  
Visual Contour ◽  
Related Potentials ◽  
Intermediate Performance

Abstract Background Accurate perception of visual contours is essential for seeing and differentiating objects in the environment. Both the ability to detect visual contours and the influence of perceptual context created by surrounding stimuli are diminished in people with schizophrenia (SCZ). The central aim of the present study was to better understand the biological underpinnings of impaired contour integration and weakened effects of perceptual context. Additionally, we sought to determine whether visual perceptual abnormalities reflect genetic factors in SCZ and are present in other severe mental disorders. Methods We examined behavioral data and event-related potentials (ERPs) collected during the perception of simple linear contours embedded in similar background stimuli in 27 patients with SCZ, 23 patients with bipolar disorder (BP), 23 first-degree relatives of SCZ, and 37 controls. Results SCZ exhibited impaired visual contour detection while BP exhibited intermediate performance. The orientation of neighboring stimuli (i.e. flankers) relative to the contour modulated perception across all groups, but SCZ exhibited weakened suppression by the perceptual context created by flankers. Late visual (occipital P2) and cognitive (centroparietal P3) neural responses showed group differences and flanker orientation effects, unlike earlier ERPs (occipital P1 and N1). Moreover, behavioral effects of flanker context on contour perception were correlated with modulation in P2 & P3 amplitudes. Conclusion In addition to replicating and extending findings of abnormal contour integration and visual context modulation in SCZ, we provide novel evidence that the abnormal use of perceptual context is associated with higher-order sensory and cognitive processes.

scholarly journals Ethylene regulates post-germination seedling growth in wheat through spatial and temporal modulation of ABA/GA balance

2019 ◽  
Vol 71 (6) ◽  
pp. 1985-2004 ◽  
Author(s):  
Menghan Sun ◽  
Pham Anh Tuan ◽  
Marta S Izydorczyk ◽  
Belay T Ayele
Keyword(s):  
Transcriptional Regulation ◽  
Seedling Growth ◽  
Molecular Mechanisms ◽  
Starch Degradation ◽  
Aba Signaling ◽  
Temporal Modulation ◽  
Aba Metabolism ◽  
Radicle Protrusion ◽  
Storage Starch

Abstract This study aimed to gain insights into the molecular mechanisms underlying the role of ethylene in regulating germination and seedling growth in wheat by combining pharmacological, molecular, and metabolomics approaches. Our study showed that ethylene does not affect radicle protrusion but controls post-germination endospermic starch degradation through transcriptional regulation of specific α-amylase and α-glucosidase genes, and this effect is mediated by alteration of endospermic bioactive gibberellin (GA) levels, and GA sensitivity via expression of the GA signaling gene, TaGAMYB. Our data implicated ethylene as a positive regulator of embryo axis and coleoptile growth through transcriptional regulation of specific TaEXPA genes. These effects were associated with modulation of GA levels and sensitivity, through expression of GA metabolism (TaGA20ox1, TaGA3ox2, and TaGA2ox6) and signaling (TaGAMYB) genes, respectively, and/or the abscisic acid (ABA) level and sensitivity, via expression of specific ABA metabolism (TaNCED2 or TaCYP707A1) and signaling (TaABI3) genes, respectively. Ethylene appeared to regulate the expression of TaEXPA3 and thereby root growth through its control of coleoptile ABA metabolism, and root ABA signaling via expression of TaABI3 and TaABI5. These results show that spatiotemporal modulation of ABA/GA balance mediates the role of ethylene in regulating post-germination storage starch degradation and seedling growth in wheat.

scholarly journals Role of onset asynchrony in contour integration

2002 ◽  
Vol 42 (1) ◽  
pp. 1-9 ◽  
Author(s):  
William H.A Beaudot
Keyword(s):  
Contour Integration ◽  
Onset Asynchrony

Poster #T115 KANIZSA SHAPE PERCEPTION AND CONTOUR INTEGRATION IN SCHIZOPHRENIA: WHAT IS THE ROLE OF SPATIAL FREQUENCY?

2014 ◽  
Vol 153 ◽  
pp. S330
Author(s):  
Brian P. Keane ◽  
Danielle Paterno ◽  
Genna Erlikhman ◽  
Sabine Kastner ◽  
Steven Silverstein
Keyword(s):  
Spatial Frequency ◽  
Shape Perception ◽  
Contour Integration

Effects of Aging on Visual Contour Integration and Segmentation

2011 ◽  
Vol 52 (7) ◽  
pp. 3955 ◽  
Author(s):  
Clara Casco ◽  
Valentina Robol ◽  
Michele Barollo ◽  
Selene Cansino
Keyword(s):  
Contour Integration ◽  
Visual Contour ◽  
Effects Of Aging

scholarly journals Heritability of human visual contour integration—an integrated genomic study

2019 ◽  
Vol 27 (12) ◽  
pp. 1867-1875
Author(s):  
Zijian Zhu ◽  
Biqing Chen ◽  
Ren Na ◽  
Wan Fang ◽  
Wenxia Zhang ◽  
...  
Keyword(s):  
Contour Integration ◽  
Genomic Study ◽  
Visual Contour

Development of visual contour integration in children with migraine without aura

Cephalalgia ◽  
2011 ◽  
Vol 31 (9) ◽  
pp. 1048-1056 ◽  
Author(s):  
Gábor Braunitzer ◽  
Alice Rokszin ◽  
Jenő Kóbor ◽  
Attila Nagy ◽  
László Sztriha ◽  
...  
Keyword(s):  
Migraine Without Aura ◽  
Random Noise ◽  
Ion Homeostasis ◽  
Brain Structures ◽  
Contour Integration ◽  
Control Group ◽  
Functional Deficits ◽  
Significant Difference ◽  
Noise Density ◽  
Visual Contour

Introduction: As migraine attacks pose insult to cerebral circulation and ion homeostasis, migraine has the potential to interfere with the development of different brain structures, producing functional deficits. It is known that visual contour integration (CI) is a function with a protracted development. Therefore, we sought to establish whether migraine interferes with its development. Methods: Forty-eight migraineurs (without aura) and 48 age- and sex-matched controls participated in the study, divided into three cohorts by age. Stimuli were presented on cards with a contour consisting of Gabor patches embedded in random noise. Difficulty was varied by the manipulation of relative noise density. The task was to identify and show the contour. Results: A significant difference was found between the performance of migraineurs and controls in the 10–14-year-old and 15–18-year-old cohorts ( p < 0.05). Development between all three cohorts was significant in the control group ( p < 0.017), while it was not significant in migraineurs between 6 and 14 years. Correlation between age and CI threshold was stronger in controls than in migraineurs. Conclusion: Children with paediatric migraine exhibited a less marked development in the Gabor patch-based CI task.

scholarly journals Infants Discriminate Voicing and Place of Articulation With Reduced Spectral and Temporal Modulation Cues

2015 ◽  
Vol 58 (3) ◽  
pp. 1033-1042 ◽  
Author(s):  
Laurianne Cabrera ◽  
Christian Lorenzi ◽  
Josiane Bertoncini
Keyword(s):  
Processing Condition ◽  
Stop Consonants ◽  
Temporal Modulation ◽  
Place Of Articulation ◽  
Phonetic Information ◽  
Young Infants ◽  
Speech Cues ◽  
Phonetic Contrasts ◽  
Visual Habituation

Purpose This study assessed the role of spectro-temporal modulation cues in the discrimination of 2 phonetic contrasts (voicing and place) for young infants. Method A visual-habituation procedure was used to assess the ability of French-learning 6-month-old infants with normal hearing to discriminate voiced versus unvoiced (/aba/-/apa/) and labial versus dental (/aba/-/ada/) stop consonants. The stimuli were processed by tone-excited vocoders to degrade frequency-modulation cues while preserving: (a) amplitude-modulation (AM) cues within 32 analysis frequency bands, (b) slow AM cues only (<16 Hz) within 32 bands, and (c) AM cues within 8 bands. Results Infants exhibited discrimination responses for both phonetic contrasts in each processing condition. However, when fast AM cues were degraded, infants required a longer exposure to vocoded stimuli to reach the habituation criterion. Conclusions Altogether, these results indicate that the processing of modulation cues conveying phonetic information on voicing and place is “functional” at 6 months. The data also suggest that the perceptual weight of fast AM speech cues may change during development.

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