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Global processing in amblyopia: a review.

Hamm LM, Black J, Dai S, Thompson B - Front Psychol (2014)

Bottom Line: There is evidence that the effects of amblyopia extend beyond the primary visual cortex to regions of the dorsal and ventral extra-striate visual cortex involved in visual integration.These tasks appear to be differentially affected by amblyopia.In general, observers with unilateral amblyopia appear to show deficits for local spatial processing and global tasks that require the segregation of signal from noise.

View Article: PubMed Central - PubMed

Affiliation: Department of Optometry and Vision Science, University of Auckland Auckland, New Zealand.

ABSTRACT
Amblyopia is a neurodevelopmental disorder of the visual system that is associated with disrupted binocular vision during early childhood. There is evidence that the effects of amblyopia extend beyond the primary visual cortex to regions of the dorsal and ventral extra-striate visual cortex involved in visual integration. Here, we review the current literature on global processing deficits in observers with either strabismic, anisometropic, or deprivation amblyopia. A range of global processing tasks have been used to investigate the extent of the cortical deficit in amblyopia including: global motion perception, global form perception, face perception, and biological motion. These tasks appear to be differentially affected by amblyopia. In general, observers with unilateral amblyopia appear to show deficits for local spatial processing and global tasks that require the segregation of signal from noise. In bilateral cases, the global processing deficits are exaggerated, and appear to extend to specialized perceptual systems such as those involved in face processing.

No MeSH data available.


Related in: MedlinePlus

Summary of local and global processing deficits in unilateral and bilateral amblyopia. Panel (A) depicts general trends relating to unilateral amblyopia and panel (B) shows additional trends for bilateral amblyopia. In each panel, example stimuli are shown with spatial (ventral) tasks presented to the left of each panel and temporal (dorsal) tasks to the right. In panel (A) local tasks are shown at the top of the panel, global tasks in the middle, and more complex tasks at the bottom. In panel (B), all tasks are global with more complex global tasks shown in the bottom row. Tasks with no highlighting are not specifically affected by amblyopia. Yellow highlighting indicates a deficit for the amblyopic eye only and green indicates a deficit for both eyes. The luminance of the color (dark or light) indicates how consistent the specific deficit is across studies, with darker colors representing consistent deficits. Three main trends are notable in panel (A). (A1) Local spatial deficits are more pronounced than local temporal deficits. These deficits are present in the amblyopic, but generally not the fellow eye. (A2) Global motion tasks requiring the segregation of signal from noise show more consistent deficits in both the amblyopic and fellow eye when compared to global form tasks. These deficits do not appear to be inherited from abnormalities in the processing of local temporal information [cf. trend (A1)] and the deficit does not extend to tasks requiring only motion integration. (A3) Tasks which rely on second-order processing are impaired, an effect seen in both the amblyopic and fellow eyes. Three additional trends are apparent for bilateral cases represented in panel (B). (B1) The dorsal stream deficit is exaggerated in bilateral cases. The bar graph shows normalized data from two separate studies comparing unilateral and bilateral amblyopia using Glass patterns for form, and RDKs for motion (Ellemberg et al., 2002; Lewis et al., 2002). Larger values on the Y-axis indicate a greater deficit for amblyopic eyes relative to controls. While the global form deficits are similar between unilateral and bilateral cases, the global motion deficits are much more pronounced for bilateral cases. (B2) Some aspects of face processing are impaired in bilateral amblyopia, for example, configural processing of identity. (B3) Biological motion perception, and possibly some aspects of variable face processing may be preserved after bilateral visual deprivation. See text for more details.
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Figure 7: Summary of local and global processing deficits in unilateral and bilateral amblyopia. Panel (A) depicts general trends relating to unilateral amblyopia and panel (B) shows additional trends for bilateral amblyopia. In each panel, example stimuli are shown with spatial (ventral) tasks presented to the left of each panel and temporal (dorsal) tasks to the right. In panel (A) local tasks are shown at the top of the panel, global tasks in the middle, and more complex tasks at the bottom. In panel (B), all tasks are global with more complex global tasks shown in the bottom row. Tasks with no highlighting are not specifically affected by amblyopia. Yellow highlighting indicates a deficit for the amblyopic eye only and green indicates a deficit for both eyes. The luminance of the color (dark or light) indicates how consistent the specific deficit is across studies, with darker colors representing consistent deficits. Three main trends are notable in panel (A). (A1) Local spatial deficits are more pronounced than local temporal deficits. These deficits are present in the amblyopic, but generally not the fellow eye. (A2) Global motion tasks requiring the segregation of signal from noise show more consistent deficits in both the amblyopic and fellow eye when compared to global form tasks. These deficits do not appear to be inherited from abnormalities in the processing of local temporal information [cf. trend (A1)] and the deficit does not extend to tasks requiring only motion integration. (A3) Tasks which rely on second-order processing are impaired, an effect seen in both the amblyopic and fellow eyes. Three additional trends are apparent for bilateral cases represented in panel (B). (B1) The dorsal stream deficit is exaggerated in bilateral cases. The bar graph shows normalized data from two separate studies comparing unilateral and bilateral amblyopia using Glass patterns for form, and RDKs for motion (Ellemberg et al., 2002; Lewis et al., 2002). Larger values on the Y-axis indicate a greater deficit for amblyopic eyes relative to controls. While the global form deficits are similar between unilateral and bilateral cases, the global motion deficits are much more pronounced for bilateral cases. (B2) Some aspects of face processing are impaired in bilateral amblyopia, for example, configural processing of identity. (B3) Biological motion perception, and possibly some aspects of variable face processing may be preserved after bilateral visual deprivation. See text for more details.

Mentions: The literature on global processing in amblyopia includes a range of amblyopia sub-types and psychophysical tasks; however, a number of trends are apparent across studies. These are summarized in Figure 7.


Global processing in amblyopia: a review.

Hamm LM, Black J, Dai S, Thompson B - Front Psychol (2014)

Summary of local and global processing deficits in unilateral and bilateral amblyopia. Panel (A) depicts general trends relating to unilateral amblyopia and panel (B) shows additional trends for bilateral amblyopia. In each panel, example stimuli are shown with spatial (ventral) tasks presented to the left of each panel and temporal (dorsal) tasks to the right. In panel (A) local tasks are shown at the top of the panel, global tasks in the middle, and more complex tasks at the bottom. In panel (B), all tasks are global with more complex global tasks shown in the bottom row. Tasks with no highlighting are not specifically affected by amblyopia. Yellow highlighting indicates a deficit for the amblyopic eye only and green indicates a deficit for both eyes. The luminance of the color (dark or light) indicates how consistent the specific deficit is across studies, with darker colors representing consistent deficits. Three main trends are notable in panel (A). (A1) Local spatial deficits are more pronounced than local temporal deficits. These deficits are present in the amblyopic, but generally not the fellow eye. (A2) Global motion tasks requiring the segregation of signal from noise show more consistent deficits in both the amblyopic and fellow eye when compared to global form tasks. These deficits do not appear to be inherited from abnormalities in the processing of local temporal information [cf. trend (A1)] and the deficit does not extend to tasks requiring only motion integration. (A3) Tasks which rely on second-order processing are impaired, an effect seen in both the amblyopic and fellow eyes. Three additional trends are apparent for bilateral cases represented in panel (B). (B1) The dorsal stream deficit is exaggerated in bilateral cases. The bar graph shows normalized data from two separate studies comparing unilateral and bilateral amblyopia using Glass patterns for form, and RDKs for motion (Ellemberg et al., 2002; Lewis et al., 2002). Larger values on the Y-axis indicate a greater deficit for amblyopic eyes relative to controls. While the global form deficits are similar between unilateral and bilateral cases, the global motion deficits are much more pronounced for bilateral cases. (B2) Some aspects of face processing are impaired in bilateral amblyopia, for example, configural processing of identity. (B3) Biological motion perception, and possibly some aspects of variable face processing may be preserved after bilateral visual deprivation. See text for more details.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4060804&req=5

Figure 7: Summary of local and global processing deficits in unilateral and bilateral amblyopia. Panel (A) depicts general trends relating to unilateral amblyopia and panel (B) shows additional trends for bilateral amblyopia. In each panel, example stimuli are shown with spatial (ventral) tasks presented to the left of each panel and temporal (dorsal) tasks to the right. In panel (A) local tasks are shown at the top of the panel, global tasks in the middle, and more complex tasks at the bottom. In panel (B), all tasks are global with more complex global tasks shown in the bottom row. Tasks with no highlighting are not specifically affected by amblyopia. Yellow highlighting indicates a deficit for the amblyopic eye only and green indicates a deficit for both eyes. The luminance of the color (dark or light) indicates how consistent the specific deficit is across studies, with darker colors representing consistent deficits. Three main trends are notable in panel (A). (A1) Local spatial deficits are more pronounced than local temporal deficits. These deficits are present in the amblyopic, but generally not the fellow eye. (A2) Global motion tasks requiring the segregation of signal from noise show more consistent deficits in both the amblyopic and fellow eye when compared to global form tasks. These deficits do not appear to be inherited from abnormalities in the processing of local temporal information [cf. trend (A1)] and the deficit does not extend to tasks requiring only motion integration. (A3) Tasks which rely on second-order processing are impaired, an effect seen in both the amblyopic and fellow eyes. Three additional trends are apparent for bilateral cases represented in panel (B). (B1) The dorsal stream deficit is exaggerated in bilateral cases. The bar graph shows normalized data from two separate studies comparing unilateral and bilateral amblyopia using Glass patterns for form, and RDKs for motion (Ellemberg et al., 2002; Lewis et al., 2002). Larger values on the Y-axis indicate a greater deficit for amblyopic eyes relative to controls. While the global form deficits are similar between unilateral and bilateral cases, the global motion deficits are much more pronounced for bilateral cases. (B2) Some aspects of face processing are impaired in bilateral amblyopia, for example, configural processing of identity. (B3) Biological motion perception, and possibly some aspects of variable face processing may be preserved after bilateral visual deprivation. See text for more details.
Mentions: The literature on global processing in amblyopia includes a range of amblyopia sub-types and psychophysical tasks; however, a number of trends are apparent across studies. These are summarized in Figure 7.

Bottom Line: There is evidence that the effects of amblyopia extend beyond the primary visual cortex to regions of the dorsal and ventral extra-striate visual cortex involved in visual integration.These tasks appear to be differentially affected by amblyopia.In general, observers with unilateral amblyopia appear to show deficits for local spatial processing and global tasks that require the segregation of signal from noise.

View Article: PubMed Central - PubMed

Affiliation: Department of Optometry and Vision Science, University of Auckland Auckland, New Zealand.

ABSTRACT
Amblyopia is a neurodevelopmental disorder of the visual system that is associated with disrupted binocular vision during early childhood. There is evidence that the effects of amblyopia extend beyond the primary visual cortex to regions of the dorsal and ventral extra-striate visual cortex involved in visual integration. Here, we review the current literature on global processing deficits in observers with either strabismic, anisometropic, or deprivation amblyopia. A range of global processing tasks have been used to investigate the extent of the cortical deficit in amblyopia including: global motion perception, global form perception, face perception, and biological motion. These tasks appear to be differentially affected by amblyopia. In general, observers with unilateral amblyopia appear to show deficits for local spatial processing and global tasks that require the segregation of signal from noise. In bilateral cases, the global processing deficits are exaggerated, and appear to extend to specialized perceptual systems such as those involved in face processing.

No MeSH data available.


Related in: MedlinePlus