Adaptation, perceptual learning, and plasticity of brain functions

Horton, Jonathan C.; Fahle, Manfred; Mulder, Theo; Trauzettel‐Klosinski, Susanne

doi:10.1007/s00417-016-3580-y

Cited by 29 publications

(20 citation statements)

References 43 publications

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“…His diagrams of the situation (reproduced in our Translation) suggest that since the lines or edges extend over several cone diameters, the natural way to solve the problem would be to average – somehow – over the local sign values of the cones along the lengths of the contours (e.g., for vertical contours, above and below the offset). This is indeed how this paper has been widely cited: as the source of this theory (e.g., Badcock & Westheimer, 1985 ; Horton, Fahle, Mulder & Trauzettel-Klosinski, 2017 ; Matin, 1972 ; Levi & Waugh, 1996 ; Watt & Morgan, 1983 ; Westheimer, 2016 ; Westheimer & McKee, 1977 ). 3 In consequence, some have claimed that Hering’s theory has been disproved because dot stimuli can exhibit hyperacuity (e.g., Ludvigh, 1953 ; Westheimer & McKee, 1977 ), and so too can curved line stimuli ( Matin, 1972 ) – although in its defence, many others have shown length summation in hyperacuity experiments (e.g., Averill & Weymouth, 1925 ; French, 1920 ), if with qualifications ( Wang & Levi, 1994 ).…”

Section: Introductionsupporting

confidence: 54%

Ewald Hering’s (1899) On the Limits of Visual Acuity: A Translation and Commentary

2018

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Towards the end of the 19th Century, Hering and Helmholtz were arguing about the fineness of visual acuity. In a talk given in 1899, Hering finally established beyond reasonable doubt that humans can see spatial displacements smaller than the diameter of a foveal cone receptor, an ability we nowadays call ‘hyperacuity’ and still the topic of active research. Hering suggested that this ability is made manifest by averaging across the range of locations stimulated during miniature eye movements. However, this idea was made most clear only in a footnote to this (not well known) publication of his talk and so was missed by many subsequent workers. Accordingly, particularly towards the end of the 20th Century, Hering has commonly been mis-cited as having proposed in this paper that averaging occurs purely along the lengths of the edges in the image. Here, we present in translation what Hering actually said and why. In Supplementary Material, we additionally translate accounts of some background experiments by Volkmann (1863) that were cited by Hering.

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Section: Introductionsupporting

confidence: 54%

Ewald Hering’s (1899) On the Limits of Visual Acuity: A Translation and Commentary

2018

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“…Cortical plasticity can be observed at multiple temporal scales (Horton et al 2017), ranging from short-term (seconds to minutes) to long-term (days to many months). Cortical plasticity also occurs across a wide range of spatial scales, ranging from alterations in the tuning characteristics of individual neurons up to reorganization of entire neuronal circuits (“cortical remapping”, see Wandell and Smirnakis 2009, for a review).…”

Section: Cortical Plasticity and Perceptual Learning: Two Sides Ofmentioning

confidence: 99%

Learning to see again: biological constraints on cortical plasticity and the implications for sight restoration technologies

et al. 2017

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The “bionic eye” – so long a dream of the future – is finally becoming a reality with retinal prostheses available to patients in both the US and Europe. However, clinical experience with these implants has made it apparent that the vision provided by these devices differs substantially from normal sight. Consequently, the ability to learn to make use of this abnormal retinal input plays a critical role in whether or not some functional vision is successfully regained. The goal of the present review is to summarize the vast basic science literature on developmental and adult cortical plasticity with an emphasis on how this literature might relate to the field of prosthetic vision. We begin with describing the distortion and information loss likely to be experienced by visual prosthesis users. We then define cortical plasticity and perceptual learning, and describe what is known, and what is unknown, about visual plasticity across the hierarchy of brain regions involved in visual processing, and across different stages of life. We close by discussing what is known about brain plasticity in sight restoration patients and discuss biological mechanisms that might eventually be harnessed to improve visual learning in these patients.

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“…Homonymous hemianopia (HH) causes impaired spatial orientation and diminished quality of life [ 1 , 2 ]. Much research exists on adult patients with HH [ 3 – 8 ], but only few studies on children. To our knowledge, the present study is the first using visual search training (VST), eye movements and exploration of relevance for daily living in children with HH.…”

Section: Introductionmentioning

confidence: 99%

Effects of visual search training in children with hemianopia

et al. 2018

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BackgroundThis study investigates the effect of a new computer-based visual search training (VST) that was adapted for children with homonymous hemianopia (HH).Methods22 children with HH (median age 11 years, 8 months: 6y6m-19y2m) trained at home for 15 minutes twice/day, 5 days/week, for 6 weeks. To assess performance before training (T1), directly after training (T2) and 6 weeks after the end of training (T3), we measured search times (STs) during on-screen search (with eye tracking), and in a real life search task. Additional variables analyzed during on-screen search were numbers, amplitudes, and durations of saccades, their directional patterns and the proportional number of saccades into the non-seeing field. The latter was the main variable during free viewing. Sixteen healthy age-matched children, who did not undergo the training, served as comparison group. Quality of Life (QoL)-questionnaires were also applied.ResultsSTs of the patients decreased significantly during the training and all search performance tests. This improvement persisted 6 weeks after the end of the training. Saccade amplitudes increased, total number of saccades to find the target decreased, and the proportional number of saccades to the non-seeing side increased. These changes were maintained at T3. Saccade durations did not change. During free viewing, saccades were equally distributed to both sides before and after training. Patients reported improvements in QoL and activities of daily living. Performance in the healthy children did not change by simply repeating the visual search test.ConclusionsThe improvement in STs in all search tasks, larger and fewer saccades, and an improved search strategy after VST suggests that the children with HH benefited from the training. The maintained improvement at T3 and the improvement in the real life search task indicate that the newly developed search strategy persists and can be applied to everyday life.

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Adaptation, perceptual learning, and plasticity of brain functions

Cited by 29 publications

References 43 publications

Ewald Hering’s (1899) On the Limits of Visual Acuity: A Translation and Commentary

Ewald Hering’s (1899) On the Limits of Visual Acuity: A Translation and Commentary

Learning to see again: biological constraints on cortical plasticity and the implications for sight restoration technologies

Effects of visual search training in children with hemianopia

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