scholarly journals Relative efficacy of global motion versus contrast training early after stroke for recovering contrast sensitivity in cortical blindness

2018 ◽  
Vol 18 (10) ◽  
pp. 267 ◽  
Author(s):  
Elizabeth Saionz ◽  
Duje Tadin ◽  
Krystel Huxlin
Keyword(s):  
Contrast Sensitivity ◽  
Cortical Blindness ◽  
Relative Efficacy ◽  
Global Motion ◽  
Motion Versus

scholarly journals The role of contrast sensitivity in global motion processing deficits in the elderly

2010 ◽  
Vol 10 (10) ◽  
pp. 15-15 ◽  
Author(s):  
H. A. Allen ◽  
C. V. Hutchinson ◽  
T. Ledgeway ◽  
P. Gayle
Keyword(s):  
Contrast Sensitivity ◽  
The Elderly ◽  
Motion Processing ◽  
Global Motion ◽  
Processing Deficits

scholarly journals Spatial Frequency Tuning and Transfer of Perceptual Learning for Motion Coherence Reflects the Tuning Properties of Global Motion Processing

Vision ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 44 ◽  
Author(s):  
Jordi Asher ◽  
Vincenzo Romei ◽  
Paul Hibbard
Keyword(s):  
Spatial Frequency ◽  
Perceptual Learning ◽  
Contrast Sensitivity ◽  
High Frequency ◽  
Frequency Tuning ◽  
Low Frequency ◽  
Motion Processing ◽  
Global Motion ◽  
Low Frequencies ◽  
Motion Coherence

Perceptual learning is typically highly specific to the stimuli and task used during training. However, recently, it has been shown that training on global motion can transfer to untrained tasks, reflecting the generalising properties of mechanisms at this level of processing. We investigated (i) if feedback was required for learning in a motion coherence task, (ii) the transfer across the spatial frequency of training on a global motion coherence task and (iii) the transfer of this training to a measure of contrast sensitivity. For our first experiment, two groups, with and without feedback, trained for ten days on a broadband motion coherence task. Results indicated that feedback was a requirement for robust learning. For the second experiment, training consisted of five days of direction discrimination using one of three motion coherence stimuli (where individual elements were comprised of either broadband Gaussian blobs or low- or high-frequency random-dot Gabor patches), with trial-by-trial auditory feedback. A pre- and post-training assessment was conducted for each of the three types of global motion coherence conditions and high and low spatial frequency contrast sensitivity (both without feedback). Our training paradigm was successful at eliciting improvement in the trained tasks over the five days. Post-training assessments found evidence of transfer for the motion coherence task exclusively for the group trained on low spatial frequency elements. For the contrast sensitivity tasks, improved performance was observed for low- and high-frequency stimuli, following motion coherence training with broadband stimuli, and for low-frequency stimuli, following low-frequency training. Our findings are consistent with perceptual learning, which depends on the global stage of motion processing in higher cortical areas, which is broadly tuned for spatial frequency, with a preference for low frequencies.

scholarly journals Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children

2015 ◽  
Vol 115 ◽  
pp. 83-91 ◽  
Author(s):  
Arijit Chakraborty ◽  
Nicola S. Anstice ◽  
Robert J. Jacobs ◽  
Nabin Paudel ◽  
Linda L. LaGasse ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Motion Perception ◽  
Coherent Motion ◽  
Global Motion ◽  
Motion Direction ◽  
Direction Discrimination

scholarly journals Spatial frequency tuning of perceptual learning and transfer in global motion

2018 ◽  
Author(s):  
Jordi M Asher ◽  
Vincenzo Romei ◽  
Paul B Hibbard
Keyword(s):  
Spatial Frequency ◽  
Perceptual Learning ◽  
Contrast Sensitivity ◽  
Frequency Tuning ◽  
Training Transfer ◽  
Global Motion ◽  
Motion Condition ◽  
Motion Coherence ◽  
Low Pass ◽  
Increased Sensitivity

AbstractPerceptual learning is typically highly specific to the stimuli and task used during training. However, recently it has been shown that training on global motion can transfer to untrained tasks, reflecting the generalising properties of mechanisms at this level of processing. We investigated a) if feedback was required for learning when using an equivalent noise global motion coherence task, and b) the transfer across spatial frequency of training on a global motion coherence task, and the transfer of this training to a measure of contrast sensitivity. For our first experiment two groups, with and without feedback, trained for ten days on a broadband global motion coherence task. Results indicated that feedback was a requirement for learning. For the second experiment training consisted of five days of direction discrimination on one of three global motion tasks (broadband, low or high frequency random-dot Gabors), with trial-by-trial auditory feedback. A pre- and post-training assessment was also conducted, consisting of all three types of global motion stimuli (without feedback) and high and low spatial frequency contrast sensitivity. We predicted that if learning and transfer is cortically localised, then transfer would show specificity to the area processing the task (global motion). In this case, we would predict a broad transfer between spatial frequency conditions of global motion only. However, if transfer occurred as a result of backward generalisation, a more selective transfer would occur matching the low-pass broadband tuning of the area processing global motion. Our training paradigm was successful at eliciting improvement in the trained tasks over the five days. However, post-training transfer to trained or untrained tasks was only reported for the low spatial frequency trained group. This group exhibited increased sensitivity to low spatial frequency contrast, and an improvement for the broadband global motion condition. Our findings suggest that the feedback projections from global to local stages of processing play a role in transfer.

The Effect of Video Game Training on the Vision of Adults with Bilateral Deprivation Amblyopia

2012 ◽  
Vol 25 (5) ◽  
pp. 493-520 ◽  
Author(s):  
Seong Taek Jeon ◽  
Daphne Maurer ◽  
Terri L. Lewis
Keyword(s):  
Contrast Sensitivity ◽  
Video Game ◽  
Critical Period ◽  
Single Letter ◽  
Field Of View ◽  
Global Motion ◽  
Temporal Contrast ◽  
Useful Field Of View ◽  
History Of ◽  
Abnormal Visual

Amblyopia is a condition involving reduced acuity caused by abnormal visual input during a critical period beginning shortly after birth. Amblyopia is typically considered to be irreversible during adulthood. Here we provide the first demonstration that video game training can improve at least some aspects of the vision of adults with bilateral deprivation amblyopia caused by a history of bilateral congenital cataracts. Specifically, after 40 h of training over one month with an action video game, most patients showed improvement in one or both eyes on a wide variety of tasks including acuity, spatial contrast sensitivity, and sensitivity to global motion. As well, there was evidence of improvement in at least some patients for temporal contrast sensitivity, single letter acuity, crowding, and feature spacing in faces, but not for useful field of view. The results indicate that, long after the end of the critical period for damage, there is enough residual plasticity in the adult visual system to effect improvements, even in cases of deep amblyopia caused by early bilateral deprivation.

scholarly journals Use it before you lose it: greater efficacy of visual training for recovering contrast sensitivity in subacute cortical blindness

2019 ◽  
Vol 19 (15) ◽  
pp. 33
Author(s):  
Elizabeth L. Saionz ◽  
Michael D. Melnick ◽  
Duje Tadin ◽  
Krystel R. Huxlin
Keyword(s):  
Contrast Sensitivity ◽  
Cortical Blindness ◽  
Visual Training

scholarly journals Motion versus Position in the Perception of Head-Centred Movement

Perception ◽  
10.1068/p3256 ◽  
2002 ◽  
Vol 31 (5) ◽  
pp. 603-615 ◽  
Author(s):  
Tom C A Freeman ◽  
Jane H Sumnall
Keyword(s):  
Eye Movement ◽  
Linear Trend ◽  
Motion Aftereffect ◽  
Phenomenal Experience ◽  
Global Motion ◽  
Stationary Object ◽  
Retinal Motion ◽  
Random Dot Patterns ◽  
Perceived Motion ◽  
Motion Versus

Observers can recover motion with respect to the head during an eye movement by comparing signals encoding retinal motion and the velocity of pursuit. Evidently there is a mismatch between these signals because perceived head-centred motion is not always veridical. One example is the Filehne illusion, in which a stationary object appears to move in the opposite direction to pursuit. Like the motion aftereffect, the phenomenal experience of the Filehne illusion is one in which the stimulus moves but does not seem to go anywhere. This raises problems when measuring the illusion by motion nulling because the more traditional technique confounds perceived motion with changes in perceived position. We devised a new nulling technique using global-motion stimuli that degraded familiar position cues but preserved cues to motion. Stimuli consisted of random-dot patterns comprising signal and noise dots that moved at the same retinal ‘base’ speed. Noise moved in random directions. In an eye-stationary speed-matching experiment we found noise slowed perceived retinal speed as ‘coherence strength’ (ie percentage of signal) was reduced. The effect occurred over the two-octave range of base speeds studied and well above direction threshold. When the same stimuli were combined with pursuit, observers were able to null the Filehne illusion by adjusting coherence. A power law relating coherence to retinal base speed fit the data well with a negative exponent. Eye-movement recordings showed that pursuit was quite accurate. We then tested the hypothesis that the stimuli found at the null-points appeared to move at the same retinal speed. Two observers supported the hypothesis, a third partially, and a fourth showed a small linear trend. In addition, the retinal speed found by the traditional Filehne technique was similar to the matches obtained with the global-motion stimuli. The results provide support for the idea that speed is the critical cue in head-centred motion perception.

Sign in / Sign up

Export Citation Format

Share Document