scholarly journals Age-Related Decline of Low-Spatial-Frequency Bias in Context-Dependent Visual Size Perception

2019 ◽  
Vol 10 ◽  
Author(s):  
Anqi Wang ◽  
Shengnan Zhu ◽  
Lihong Chen ◽  
Wenbo Luo
Keyword(s):  
Spatial Frequency ◽  
Size Perception ◽  
Age Related ◽  
Context Dependent ◽  
Visual Size

scholarly journals Low-spatial-frequency bias in context-dependent visual size perception

2018 ◽  
Vol 18 (8) ◽  
pp. 2 ◽  
Author(s):  
Lihong Chen ◽  
Congying Qiao ◽  
Yi Jiang
Keyword(s):  
Spatial Frequency ◽  
Size Perception ◽  
Context Dependent ◽  
Visual Size

Anodal Occipital Transcranial Direct Current Stimulation Enhances Perceived Visual Size Illusions

2020 ◽  
pp. 1-8
Author(s):  
Anqi Wang ◽  
Lihong Chen ◽  
Yi Jiang
Keyword(s):  
Visual Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Size Perception ◽  
Central Target ◽  
Direct Current Stimulation ◽  
Visual Areas ◽  
Early Visual Cortex ◽  
Context Dependent ◽  
Visual Size

Human early visual cortex has long been suggested to play a crucial role in context-dependent visual size perception through either lateral interaction or feedback projections from higher to lower visual areas. We investigated the causal contribution of early visual cortex to context-dependent visual size perception using the technique of transcranial direct current stimulation and two well-known size illusions (i.e., the Ebbinghaus and Ponzo illusions) and further elucidated the underlying mechanism that mediates the effect of transcranial direct current stimulation over early visual cortex. The results showed that the magnitudes of both size illusions were significantly increased by anodal stimulation relative to sham stimulation but left unaltered by cathodal stimulation. Moreover, the anodal effect persisted even when the central target and surrounding inducers of the Ebbinghaus configuration were presented to different eyes, with the effect lasting no more than 15 min. These findings provide compelling evidence that anodal occipital stimulation enhances the perceived visual size illusions, which is possibly mediated by weakening the suppressive function of the feedback connections from higher to lower visual areas. Moreover, the current study provides further support for the causal role of early visual cortex in the neural processing of context-dependent visual size perception.

A motor signal and ?visual? size perception

1996 ◽  
Vol 110 (3) ◽  
Author(s):  
DavidP. Carey ◽  
Kevin Allan
Keyword(s):  
Size Perception ◽  
Motor Signal ◽  
Visual Size

scholarly journals Development of a sensory and perceptual assessment test for psychosis and schizophrenia

2020 ◽  
Author(s):  
Maria Lucia de Bustamante Simas ◽  
Ana Cristina Taunay C. A. Maranhão ◽  
Flora Silva Teixeira ◽  
Aline Mendes Lacerda ◽  
Carlos Henrique Resende Freire ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Size Perception ◽  
Psychotic Symptoms ◽  
Control Group ◽  
Salvador Dali ◽  
Ex Post ◽  
Perceptual Test ◽  
Quasi Experimental ◽  
Visual Size ◽  
Experimental Group

Results from the development of a novel sensory and perceptual test to assess the level of altered visual size perception in people with schizophrenia are presented. Here we compare the performances in a visual sensory and perceptual test between a control group and an experimental group of people diagnosed with schizophrenia. We have been using paintings by Salvador Dalí and Rorschach plates to assess images size perception. In this transversal, ex-post-fact and quasi-experimental study we show differences between EG (Experimental Group) and CG (Control Group). Schizophrenics in-patients as compared to controls perceived sizes about 1.3 fold greater than healthy volunteers (p=0.006), thus showing that size perception is altered in schizophrenia. Together with previous results, this particular sensory test for size perception seems to be a useful assessment tool to evaluate the degree and severity of psychotic symptoms in prodromal schizophrenic states, and neuropsychiatric patients in general. It may help prevent acute crisis with proper, and most likely, lower dosages of medication.

Size Discrimination with Low Spatial Frequencies

Perception ◽  
1982 ◽  
Vol 11 (6) ◽  
pp. 707-720 ◽  
Author(s):  
Robert A Smith
Keyword(s):  
Fourier Spectrum ◽  
Low Frequency ◽  
Current Theory ◽  
Size Perception ◽  
Size Discrimination ◽  
Low Frequencies ◽  
Spatial Frequencies ◽  
Vertical Bars ◽  
The Fourier Transform ◽  
Visual Size

The hypothesis that visual size is determined from the low-frequency Fourier spectrum of the image has been tested in a variety of ways. The fact that size discrimination of vertical bars is unimpaired when high spatial frequencies are filtered out of the image by blurring, and the fact that spatial-frequency adaptation alters perceived size, argue in favor of such hypothesis. However, the hypothesis is weakened by the observation that discrimination is also unimpaired by filtering low frequencies out of the image and by the observation that some manipulations which alter the Fourier transform produce no corresponding perceptual change. No current theory of size perception appears to fit all of these data.

scholarly journals Age-Related Differences in Spatial Frequency Processing during Scene Categorization

PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0134554 ◽  
Author(s):  
Stephen Ramanoël ◽  
Louise Kauffmann ◽  
Emilie Cousin ◽  
Michel Dojat ◽  
Carole Peyrin
Keyword(s):  
Spatial Frequency ◽  
Scene Categorization ◽  
Age Related ◽  
Frequency Processing

scholarly journals Residual abilities in age-related macular degeneration to process spatial frequencies during natural scene categorization

2011 ◽  
Vol 28 (6) ◽  
pp. 529-541 ◽  
Author(s):  
BENOIT MUSEL ◽  
RUXANDRA HERA ◽  
SYLVIE CHOKRON ◽  
DAVID ALLEYSSON ◽  
CHRISTOPHE CHIQUET ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Macular Degeneration ◽  
Reaction Times ◽  
Age Related Macular Degeneration ◽  
Natural Scenes ◽  
Natural Scene ◽  
Scene Categorization ◽  
Age Related ◽  
Spatial Frequencies ◽  
Healthy Participants

AbstractAge-related macular degeneration (AMD) is characterized by a central vision loss. We explored the relationship between the retinal lesions in AMD patients and the processing of spatial frequencies in natural scene categorization. Since the lesion on the retina is central, we expected preservation of low spatial frequency (LSF) processing and the impairment of high spatial frequency (HSF) processing. We conducted two experiments that differed in the set of scene stimuli used and their exposure duration. Twelve AMD patients and 12 healthy age-matched participants in Experiment 1 and 10 different AMD patients and 10 healthy age-matched participants in Experiment 2 performed categorization tasks of natural scenes (Indoors vs. Outdoors) filtered in LSF and HSF. Experiment 1 revealed that AMD patients made more no-responses to categorize HSF than LSF scenes, irrespective of the scene category. In addition, AMD patients had longer reaction times to categorize HSF than LSF scenes only for indoors. Healthy participants’ performance was not differentially affected by spatial frequency content of the scenes. In Experiment 2, AMD patients demonstrated the same pattern of errors as in Experiment 1. Furthermore, AMD patients had longer reaction times to categorize HSF than LSF scenes, irrespective of the scene category. Again, spatial frequency processing was equivalent for healthy participants. The present findings point to a specific deficit in the processing of HSF information contained in photographs of natural scenes in AMD patients. The processing of LSF information is relatively preserved. Moreover, the fact that the deficit is more important when categorizing HSF indoors, may lead to new perspectives for rehabilitation procedures in AMD.

Changes in visual size perception in Schizophrenia and Depression

2020 ◽  
Vol 14 (4) ◽  
pp. 140-153
Author(s):  
Aline Mendes Lacerda ◽  
Maria Lúcia De Bustamante Simas ◽  
Geórgia Mônica Marques de Menezes
Keyword(s):  
Visual Angle ◽  
Size Perception ◽  
Control Group ◽  
Schizophrenia Group ◽  
Depression Group ◽  
Visual Size

The objective of this research was to measure possible changes in visual size perception of patients with depression and schizophrenia. Three groups were compared: Control Group (CG), Schizophrenia Group (SchG) and Depression Group (DepG). The diameter of the first figure seen by the participants in each painting was recorded in degrees of visual angle. The SchG perceived images 1.47 larger than CG and the DepG 1.28 larger than CG, whereas SchG selected images 1.15 larger than DepG, F (2, 57) = 17.677, p < .0001. These findings suggest there are changes in visual size perception related to depression and schizophrenia.

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