Trunk rotation affects temporal order judgments: evidence from spatial neglect

Abstract

Spatial neglect is a common consequence of brain injury where individuals fail to respond to stimuli presented on their contralesional side. It has been argued that beyond the spatial bias, these individuals also tend to exhibit temporal perceptual deficits. Here we demonstrate that the deficits affecting the temporal dynamics of attentional deployment are in fact modulated by spatial position. Specifically, we observed the severe bias to the right affecting the time-course of visual awareness in chronic neglect is enhanced when stimuli are presented on the contralesional side of the trunk, while keeping retinal and head-centered coordinates constant. We did not find this pattern in right brain damaged patients without neglect or in patients who had recovered from neglect. Our work suggests that the temporal attentional deficits observed in neglect are heavily modulated by egocentric spatial position. This provides strong evidence against models that suggest independent modules for spatial and temporal attentional functions, while also providing strong evidence that trunk position plays a dominant – if not the principal – role in spatial neglect.