A matter of time: improvement of visual temporal processing during training-induced restoration of light detection performance.

Dorothe A Poggel,Bernhard A Sabel,Bernhard Treutwein,Hans Strasburger

doi:10.3389/fpsyg.2015.00022

Abstract

The issue of how basic sensory and temporal processing are related is still unresolved. We studied temporal processing, as assessed by simple visual reaction times (RT) and double-pulse resolution (DPR), in patients with partial vision loss after visual pathway lesions and investigated whether vision restoration training (VRT), a training program designed to improve light detection performance, would also affect temporal processing. Perimetric and campimetric visual field tests as well as maps of DPR thresholds and RT were acquired before and after a 3 months training period with VRT. Patient performance was compared to that of age-matched healthy subjects. Intact visual field size increased during training. Averaged across the entire visual field, DPR remained constant while RT improved slightly. However, in transition zones between the blind and intact areas (areas of residual vision) where patients had shown between 20 and 80% of stimulus detection probability in pre-training visual field tests, both DPR and RT improved markedly. The magnitude of improvement depended on the defect depth (or degree of intactness) of the respective region at baseline. Inter-individual training outcome variability was very high, with some patients showing little change and others showing performance approaching that of healthy controls. Training-induced improvement of light detection in patients with visual field loss thus generalized to dynamic visual functions. The findings suggest that similar neural mechanisms may underlie the impairment and subsequent training-induced functional recovery of both light detection and temporal processing.

Highlights

Visual signals contain information on many different aspects of our environment
As assessed by simple visual reaction times (RT) and double-pulse resolution (DPR), in patients with partial vision loss after visual pathway lesions and investigated whether vision restoration training (VRT), a training program designed to improve light detection performance, would affect temporal processing
The two major aspects of temporal processing are the speed of visual perception as such—which can be measured, for instance, by simple visual reaction times (RTs; as explained in the methods section)—and the temporal resolution of visual perception—which can be measured for example by flicker resolution tasks

Summary

Introduction

Visual signals contain information on many different aspects of our environment. Most prominently, intensity (or contrast), spatial configuration, and temporal aspects are important dimensions of visual perception. The two major aspects of temporal processing are the speed of visual perception as such—which can be measured, for instance, by simple visual reaction times (RTs; as explained in the methods section)—and the temporal resolution of visual perception—which can be measured for example by flicker resolution tasks. These two aspects in the temporal domain (“when do I perceive?” and “how fine-grain is the perception?”) correspond basically to analogous concepts in the spatial domain (“where do I perceive?”—i.e., localization tasks—and “how fine-grain is the spatial resolution?”—i.e., can the perceiver discriminate between location A and B and what is the minimal distance between A and B that still allows that discrimination)

Methods

Results

Discussion

Conclusion