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Advancing a Model to Account for Abnormal Spatial Relationship Perception in Bulbar Cyclotorsion.

Aleci C - Cureus (2015)

Bottom Line: In both cases, we advanced bulbar torsion to be responsible for the reduced sensibility to spatial relationship along the x-coordinate.Still, a possible explanation and a tentative model accounting for the results at that time had not been provided.Such a model of the "dual horizon" seems to be able to account for the experimental finding described in the previous paper, providing a theoretical explanation for the defective sense of space in patients suffering from cyclotropia.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept of Ophthalmology, The Gradenigo Hospital ; Neuro-Ophthalmology center, University of Turin.

ABSTRACT
In a previous study dated back to 2001, a small sample of cyclotropic patients were found to be affected by abnormal spatial relationship perception (aspect ratio judgment) with increased discrimination threshold of elliptical targets oriented along the horizontal axis. The angular amount of incyclodeviation correlated significantly with the discrimination threshold along the horizontal axis. Our group made a similar finding some years later in subjects suffering from Menière's syndrome. In both cases, we advanced bulbar torsion to be responsible for the reduced sensibility to spatial relationship along the x-coordinate. Still, a possible explanation and a tentative model accounting for the results at that time had not been provided. This paper aims at making up for the gap, advancing a paradigm that explains the increased discrimination threshold in cyclotropic eyes as a function of the angular discrepancy between the horizontal coordinate on the retinal plane, corresponding to the maculopapillary axis (the "retinal horizon"), and the horizontal coordinate in the visual space (the "spatial horizon"). This angular discrepancy is posited to produce abnormal encoding of the spatial relationship of the target, leading to an unbalanced activation of the two antagonistic cellular pools responsible for the analysis of the aspect ratio at the cortical level. Such a model of the "dual horizon" seems to be able to account for the experimental finding described in the previous paper, providing a theoretical explanation for the defective sense of space in patients suffering from cyclotropia.

No MeSH data available.


Related in: MedlinePlus

The SR encoding value of the retinal detectors depends upon their position relative to the retinal horizon (I).Defective SRP in cyclotropic eyes would derive from the occurrence of an angular difference between the retinal horizon and the spatial horizon. The difference would change the position of the retinal detectors as to the spatial horizon. At the cortical level, this discrepancy would determine over-activation of the V-cellular pool compared to the H-pool (example referred to retinal horizon tilted nasally).
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FIG2: The SR encoding value of the retinal detectors depends upon their position relative to the retinal horizon (I).Defective SRP in cyclotropic eyes would derive from the occurrence of an angular difference between the retinal horizon and the spatial horizon. The difference would change the position of the retinal detectors as to the spatial horizon. At the cortical level, this discrepancy would determine over-activation of the V-cellular pool compared to the H-pool (example referred to retinal horizon tilted nasally).

Mentions: To summarize, defective SRP in cyclotropic eyes would derive from the occurrence of an angular difference between the retinal horizon and the spatial horizon due to bulbar torsion. Such a tilt of the retinal horizon would induce a shift of the retinal detectors as to the spatial horizon. At the cortical level, this discrepancy would determine over-activation of the V-cellular pool compared to the H-pool (Figure 2).


Advancing a Model to Account for Abnormal Spatial Relationship Perception in Bulbar Cyclotorsion.

Aleci C - Cureus (2015)

The SR encoding value of the retinal detectors depends upon their position relative to the retinal horizon (I).Defective SRP in cyclotropic eyes would derive from the occurrence of an angular difference between the retinal horizon and the spatial horizon. The difference would change the position of the retinal detectors as to the spatial horizon. At the cortical level, this discrepancy would determine over-activation of the V-cellular pool compared to the H-pool (example referred to retinal horizon tilted nasally).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494463&req=5

FIG2: The SR encoding value of the retinal detectors depends upon their position relative to the retinal horizon (I).Defective SRP in cyclotropic eyes would derive from the occurrence of an angular difference between the retinal horizon and the spatial horizon. The difference would change the position of the retinal detectors as to the spatial horizon. At the cortical level, this discrepancy would determine over-activation of the V-cellular pool compared to the H-pool (example referred to retinal horizon tilted nasally).
Mentions: To summarize, defective SRP in cyclotropic eyes would derive from the occurrence of an angular difference between the retinal horizon and the spatial horizon due to bulbar torsion. Such a tilt of the retinal horizon would induce a shift of the retinal detectors as to the spatial horizon. At the cortical level, this discrepancy would determine over-activation of the V-cellular pool compared to the H-pool (Figure 2).

Bottom Line: In both cases, we advanced bulbar torsion to be responsible for the reduced sensibility to spatial relationship along the x-coordinate.Still, a possible explanation and a tentative model accounting for the results at that time had not been provided.Such a model of the "dual horizon" seems to be able to account for the experimental finding described in the previous paper, providing a theoretical explanation for the defective sense of space in patients suffering from cyclotropia.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dept of Ophthalmology, The Gradenigo Hospital ; Neuro-Ophthalmology center, University of Turin.

ABSTRACT
In a previous study dated back to 2001, a small sample of cyclotropic patients were found to be affected by abnormal spatial relationship perception (aspect ratio judgment) with increased discrimination threshold of elliptical targets oriented along the horizontal axis. The angular amount of incyclodeviation correlated significantly with the discrimination threshold along the horizontal axis. Our group made a similar finding some years later in subjects suffering from Menière's syndrome. In both cases, we advanced bulbar torsion to be responsible for the reduced sensibility to spatial relationship along the x-coordinate. Still, a possible explanation and a tentative model accounting for the results at that time had not been provided. This paper aims at making up for the gap, advancing a paradigm that explains the increased discrimination threshold in cyclotropic eyes as a function of the angular discrepancy between the horizontal coordinate on the retinal plane, corresponding to the maculopapillary axis (the "retinal horizon"), and the horizontal coordinate in the visual space (the "spatial horizon"). This angular discrepancy is posited to produce abnormal encoding of the spatial relationship of the target, leading to an unbalanced activation of the two antagonistic cellular pools responsible for the analysis of the aspect ratio at the cortical level. Such a model of the "dual horizon" seems to be able to account for the experimental finding described in the previous paper, providing a theoretical explanation for the defective sense of space in patients suffering from cyclotropia.

No MeSH data available.


Related in: MedlinePlus