The Rotating Tilted Lines Illusion

2017 ◽  
Author(s):  
Simone Gori
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Stimulus Pattern ◽  
Motion Processing ◽  
White Background ◽  
Radial Expansion ◽  
Circular Pattern ◽  
Counterclockwise Direction ◽  
The Right ◽  
Rotatory Motion

This chapter describes the Rotating-Tilted-Lines illusion , which is a new motion illusion that arises in a circular pattern composed by black, radial lines tilted to the right and presented on a white background. When one approaches the stimulus pattern, the radial lines appear to rotate in the counterclockwise direction, whereas when one recedes from it, they appear to rotate clockwise. It is the simplest pattern able to elicit illusory rotatory motion in presence of physical radial expansion. This surprising misperception of motion seems to be a result of the competition between two motion processing units in the primary visual cortex (V1, V5)

scholarly journals Disparity processing in primary visual cortex

2016 ◽  
Vol 371 (1697) ◽  
pp. 20150255 ◽  
Author(s):  
Sid Henriksen ◽  
Seiji Tanabe ◽  
Bruce Cumming
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Striate Cortex ◽  
Three Dimensional ◽  
Empirical Support ◽  
Energy Model ◽  
Correspondence Problem ◽  
Stereo Correspondence ◽  
V1 Neurons ◽  
The Right

The first step in binocular stereopsis is to match features on the left retina with the correct features on the right retina, discarding ‘false’ matches. The physiological processing of these signals starts in the primary visual cortex, where the binocular energy model has been a powerful framework for understanding the underlying computation. For this reason, it is often used when thinking about how binocular matching might be performed beyond striate cortex. But this step depends critically on the accuracy of the model, and real V1 neurons show several properties that suggest they may be less sensitive to false matches than the energy model predicts. Several recent studies provide empirical support for an extended version of the energy model, in which the same principles are used, but the responses of single neurons are described as the sum of several subunits, each of which follows the principles of the energy model. These studies have significantly improved our understanding of the role played by striate cortex in the stereo correspondence problem. This article is part of the themed issue ‘Vision in our three-dimensional world’.

Numerical relationship between neurons in the lateral geniculate nucleus and primary visual cortex in macaque monkeys

1996 ◽  
Vol 13 (3) ◽  
pp. 585-590 ◽  
Author(s):  
Ivan Suner ◽  
Pasko Rakic
Keyword(s):  
Visual Cortex ◽  
Lateral Geniculate Nucleus ◽  
Primary Visual Cortex ◽  
Rhesus Monkeys ◽  
Three Dimensional ◽  
Area 17 ◽  
Counting Method ◽  
Lateral Geniculate ◽  
Cortex Area ◽  
The Right

AbstractWe examined the numerical correlation between total populations of neurons in the lateral geniculate nucleus (LGN) and the primary visual cortex (area 17 of Brodmann) in ten cerebral hemispheres of five normal rhesus monkeys using an unbiased three-dimensional counting method. There were 1.4 ± 0.2 million and 341 ±54 million neurons in the LGN and area 17, respectively. In each animal, a larger LGN on one side was in register with a larger area 17 of the cortex on the same side. Furthermore, asymmetry in the number of neurons in both the LGN and area 17 favored the right side. However, because of small variations across subjects, correlation between the total neuron number in LGN and area 17 was weak (r = 0.29). These results suggest that the final numbers of neurons in these visual centers may be established independently or by multiple factors controlling elimination of initially overproduced neurons.

scholarly journals Intrinsic functional connectivity alterations of the primary visual cortex in patients with proliferative diabetic retinopathy: a seed-based resting-state fMRI study

2020 ◽  
Vol 11 ◽  
pp. 204201882096029
Author(s):  
Yao Yu ◽  
Dong-Yi Lan ◽  
Li-Ying Tang ◽  
Ting Su ◽  
Biao Li ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Visual Cortex ◽  
Functional Connectivity ◽  
Primary Visual Cortex ◽  
Proliferative Diabetic Retinopathy ◽  
Resting State ◽  
Visual Information ◽  
Brain Regions ◽  
Intrinsic Functional Connectivity ◽  
The Right

Purpose: In this study, we aimed to investigate the differences in the intrinsic functional connectivity (iFC) of the primary visual cortex (V1), based on resting-state functional magnetic resonance imaging (rs-fMRI), between patients with proliferative diabetic retinopathy (PDR) and healthy controls (HCs). Methods: In total, 26 patients (12 males, 14 females) with PDR and 26 HCs (12 males, 14 females), matched for sex, age, and education status, were enrolled in the study. All individuals underwent rs-fMRI scans. We acquired iFC maps and compared the differences between PDR patients and the HCs. Results: The PDR group had significantly increased FC between the left V1 and the right middle frontal gyrus (RMFG), and significantly reduced FC between the left V1 and the cuneus/calcarine/precuneus. In addition, the PDR patients had significantly increased FC between the right V1 and the right superior frontal gyrus (RSFG), and significantly reduced FC between the right V1 and the cuneus/calcarine/precuneus. The individual areas under the curve (AUCs) of FC values for the left V1 were as follows: RMFG (0.871, p < 0.001) and the cuneus/calcarine/precuneus (0.914, p < 0.001), while the AUCs of FC values for the right V1 were as follows: RSFG (0.895, p < 0.001) and the cuneus/calcarine/precuneus (0.918, p < 0.001). Conclusions: The results demonstrated that, in PDR patients, altered iFC in distinct brain regions, including regions related to visual information processing and cognition. Considering the rise in the diabetes mellitus incidence rate and the consequences of PDR, the results could provide promising clues for exploring the neural mechanisms related to PDR and possible approaches for the early identification of PDR.

Complex motion selectivity in PMLS cortex following early lesions of primary visual cortex in the cat

2007 ◽  
Vol 24 (1) ◽  
pp. 53-64 ◽  
Author(s):  
B.G. OUELLETTE ◽  
K. MINVILLE ◽  
D. BOIRE ◽  
M. PTITO ◽  
C. CASANOVA
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Motion ◽  
Neuronal Response ◽  
Temporal Frequency ◽  
Limited Range ◽  
Direction Selectivity ◽  
Motion Processing ◽  
Complex Motion ◽  
Visual Motion Cues

In the cat, the analysis of visual motion cues has generally been attributed to the posteromedial lateral suprasylvian cortex (PMLS) (Toyama et al., 1985; Rauschecker et al., 1987; Rauschecker, 1988; Kim et al., 1997). The responses of neurons in this area are not critically dependent on inputs from the primary visual cortex (VC), as lesions of VC leave neuronal response properties in PMLS relatively unchanged (Spear & Baumann, 1979; Spear, 1988; Guido et al., 1990b). However, previous studies have used a limited range of visual stimuli. In this study, we assessed whether neurons in PMLS cortex remained direction-selective to complex motion stimuli following a lesion of VC, particularly to complex random dot kinematograms (RDKs). Unilateral aspiration of VC was performed on post-natal days 7–9. Single unit extracellular recordings were performed one year later in the ipsilateral PMLS cortex. As in previous studies, a reduction in the percentage of direction selective neurons was observed with drifting sinewave gratings. We report a previously unobserved phenomenon with sinewave gratings, in which there is a greater modulation of firing rate at the temporal frequency of the stimulus in animals with a lesion of VC, suggesting an increased segregation of ON and OFF sub-regions. A significant portion of neurons in PMLS cortex were direction selective to simple (16/18) and complex (11/16) RDKs. However, the strength of direction selectivity to both stimuli was reduced as compared to normals. The data suggest that complex motion processing is still present, albeit reduced, in PMLS cortex despite the removal of VC input. The complex RDK motion selectivity is consistent with both geniculo-cortical and extra-geniculate thalamo-cortical pathways in residual direction encoding.

scholarly journals Blindsight.

2021 ◽  
Author(s):  
James Danckert ◽  
Christopher Lee Striemer ◽  
Yves Rossetti
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Spatial Localization ◽  
Visual Pathways ◽  
Motion Processing ◽  
Functional Characteristics ◽  
The Brain

For over a century research has demonstrated that damage to primary visual cortex does not eliminate all capacity for visual processing in the brain. From Riddoch’s (1917) early demonstration of intact motion processing for blind field stimuli, to the iconic work of Weiskrantz and colleagues (1974) showing reliable spatial localization, it is clear that secondary visual pathways that bypass V1 carry information to the visual brain that in turn influences behavior. In this chapter we briefly outline the history and phenomena associated with blindsight, before discussing the nature of the secondary visual pathways that support residual visual processing in the absence of V1. We finish with some speculation as to the functional characteristics of these secondary pathways.

scholarly journals Changes in visual motion processing by neurons in mature primary visual cortex (V1) following early color deprivation

2016 ◽  
Vol 16 (12) ◽  
pp. 1182
Author(s):  
Heywood Petry ◽  
Wenhao Dang ◽  
Elizabeth Johnson ◽  
Stephen Van Hooser
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Motion ◽  
Motion Processing ◽  
Visual Motion Processing

Interaction of Direction and Speed Selectivity in Cat Primary Visual Cortex

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 344-344
Author(s):  
R Satinskas ◽  
O Ruksenas ◽  
A Pleskaciauskas ◽  
D Stabinyte ◽  
H Vaitkevicius
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
High Capacity ◽  
Light Spot ◽  
Motion Processing ◽  
Preferred Direction ◽  
The Given

We have studied the selectivity for speed and direction of directionally selective (DS) cells in the primary visual cortex of the cat. Most of the 37 DS neurons tested were velocity tuned. From a set of velocities in the range from 2 to 80 deg s−1, each velocity was optimal for a certain proportion of these cells. The distribution was as follows: 2 deg s−1 was optimal for 16% of all tested neurons, 5 deg s−1 for 14%, 10 deg s−1 for 27%, 20 deg s−1 for 30%, 40 deg s−1 for 8%, and 80 deg s−1 for 5%. The preferred direction determined with a single light spot was compared with that obtained with a pair of spots moving at a mutual angle of 60° over the receptive field. For 40% of the neurons tested the preferred direction to the single moving spot coincided with that obtained with the two-spot stimulus. The responses to the latter could be successfully computed as a combination of responses to single spots moving in the given directions. This result indicates a high capacity for motion processing in the primary visual cortex of the cat.

scholarly journals Vision AfterEarly-OnsetLesions of the Occipital Cortex: II. Physiological Studies

2002 ◽  
Vol 9 (1) ◽  
pp. 27-40 ◽  
Author(s):  
M. G. Knyazeva ◽  
P. Maeder ◽  
D. C. Kiper ◽  
T. Deonna ◽  
G. M. Innocenti
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Functional Recovery ◽  
Right Hemisphere ◽  
Occipital Cortex ◽  
Quantitative Eeg ◽  
Functional Maturation ◽  
Consistent Increase ◽  
The Right

In one of two patients (MS and FJ) with bilateral, early-onset lesion of the primary visual cortex, Kiper et al. (2002) observed a considerable degree of functional recovery. To clarify the physiological mechanisms involved in the recovery, we used fMRI and quantitative EEG to study both patients. The fMRI investigations indicated that in both patients, isolated islands of the primary visual cortex are functioning, in the right hemisphere in MS and in the left in FJ. The functional recovery observed in MS roughly correlated with the functional maturation of interhemispheric connections and might reflect the role of corticocortical connectivity in visual perception. The functionality of interhemispheric connections was assessed by analyzing the changes in occipital inter-hemispheric coherence of EEG signals (ICoh) evoked by moving gratings. In the patient MS, this ICoh response was present at 7:11 y and was more mature at 9:2 y. In the more visually mpaired patient, FJ, a consistent increase in ICoh to visual stimuli could not be obtained, possibly because of the later occurrence of the lesion.

Contour from motion processing occurs in primary visual cortex

Nature ◽  
1993 ◽  
Vol 363 (6429) ◽  
pp. 541-543 ◽  
Author(s):  
Victor A. F. Lamme ◽  
Bob W. van Dijk ◽  
Henk Spekreijse
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Motion Processing
Sign in / Sign up

Export Citation Format

Share Document