Spatial remapping deficits in patients with right parietal lesions

The integrity of spatial remapping as a prerequisite for establishing a spatio-temporal contingency between successive visual images is indicated e.g. by location-based facilitatory and inhibitory priming in visual pop-out search (Maljkovic & Nakayama, 1996). It has been suggested that spatial remapping deficits occur in patients with parietal lesions, and furthermore that these deficits might contribute to visual search impairments exhibited by these patients (Pisella & Mattingley, 2004).

To analyse spatial remapping abilities in patients with right-hemispheric lesions with (PAR) and without parietal involvement (NONPAR), and healthy subjects (CON) we used a priming of pop-out paradigm in three experiments. The „control experiment“ with retinotopically equal subsequent visual search displays. The „saccade experiment“ requiring saccadic eye-movements in-between trials but nevertheless presenting subsequent visual search displays retinotopically equal, thus requiring no spatial remapping. And the „spatial remapping experiment“ requiring spatial remapping due to alternating gaze positions between subsequent trials.

In the „control experiment“, all groups showed facilitation and inhibition, with facilitation even enhanced in the PAR group. In the „saccade experiment“ facilitation and inhibition was equally present in all groups. In the „spatial remapping experiment“, NONPAR and CON group showed facilitation and inhibition. However, neither facilitation nor inhibition was preserved in the PAR group, indicating deficient spatial remapping along with right parietal lobe lesions. Implications of spatial remapping deficits, and in particular, absent facilitation and inhibition on visual search performance are discussed.

References: [1] Maljkovic and Nakayama (1996). Priming of pop-out: II. The role of position, Perception and Psychophysics, 58, 977–991. [2] Pisella and Mattingley (2004). The contribution of spatial remapping impairments to unilateral visual neglect. Neuroscience and Biobehavioral Reviews, 28, 181–200. Acknowledgements: This work is supported by a grant from the Deutsche Forschungsgemeinschaft (DFG) to P. Bublak, K. Finke, and G. Kerkhoff (project MU FOR 480 Bu 1327/2–1).