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Visual perceptual asymmetries can be modified via visual field deprivation in human adults

Begum Erten, Nuray Mustafaoglu , Huseyin Boyaci , Katja Doerschner

This project was presented at 34rd European Conference of Visual Perception (ECVP), held in Toulouse, France, August 28 – September 1, 2011. Click here to view the poster.

Begum Erten, Huseyin Boyaci and Katja Doerschner supported by a TUBITAK grant 108K398. In addition, Huseyin Boyaci and Katja Doerschner was each supported by Marie Curie IRGs 239467, and 239494, respectively.

Vertical meridian asymmetry (VMA) refers to unequal visual performance in lower and upper visual fields (VF) along the vertical meridian, with much better performance for the lower VF (Edgar and Smith 1990). Moreover, cortical activity and neural population density for the lower VF is higher than the upper VF in V1 and V2 (Liu et al 2007) suggesting a neural basis in early visual areas for VMA. In this study, we first confirmed VMA in two participants using a 2IFC orientation discrimination task at threshold level (Carrasco et al 2001). Next the same observers wore goggles that covered their lower VF for at least five days. This lower VF deprivation dramatically enhanced their performance in the upper vertical meridian with a cost of impoverished performance along the horizontal and lower vertical meridians. These results suggest that even though visual field asymmetries are likely to be based on neural architecture, this perceptual phenomenon can be altered by visual experience. Our findings are consistent with previous adaptation, deprivation and learning studies that support the possibility of cortical plasticity in adult humans and animals (Karmarkar and Dan 2006). View the  poster  for the results.