Covert orienting of attention in patients with cortical lesions and their anatomical correlate

Directing spatial attention towards task-relevant stimuli without eye movements is referred to as covert spatial attention. Here, we used new lesion mapping techniques in stroke patients with circumscribed cortical lesions to determine which anatomical structures subserve covert visual orienting. We investigated 57 stroke patients (39 patients with right- and 18 patients with left-sided lesions) and compared their performance in a covert visual attention task (Posner task) to 20 healthy age-matched controls. Analysis of lesion location contrasting the 12 patients with right-sided lesions who performed significantly worse with the other 27 right-sided stroke patients who did not show a significant deficit in the task compared to the 20 controls revealed parts of the parietal lobe (precuneus, angular gyrus) and middle temporal gyrus as task-relevant structures. Lesion analysis regarding the 4 left-sided patients with bad performance compared to the 14 patients with good performance showed that the supramarginal gyrus and superior temporal gyrus were critically involved. These lesion analyses confirm previous functional imaging data indicating that parietal and temporal structures play a key role in covert spatial attention processes and are part of a fronto-parietal attentional network.

This work was supported by the Bundesministerium für Bildung und Forschung (BMBF-Verbundprojekt "Räumliche Orientierung" 01GW0641).