Selective reorienting response of the left hemisphere to invalid visual targets in the right side of space: Relevance for the spatial neglect syndrome

In humans, damage in the right hemisphere often provokes the striking inability to attend the left side of space, i.e., left spatial neglect. Because of hemispheric specialization, patients with lesion in the left hemisphere do not usually suffer right spatial neglect. Here we re-investigate the hemispheric distribution of reorienting mechanisms in the healthy human brain and the selectivity of their response to invalid targets in the left and/or the right side of space. We report the first fMRI evidence directly supporting long-standing hypotheses on the hemispheric lateralisa- tion of mechanisms regulating orienting of spatial attention in the human brain.