Although a left-to-right and longer-to-shorter 'continuous-gradient effect' was not supported by the results, an 'extreme left-gradient effect' was suggested and discussed.

The present study explored behavioral and eye-movement measures in unilateral neglect patients in response to online bisection task (unfilled gap line). Two different tasks supported the bisection performance, a pointing and a grasping strategy. It was explored whether these different strategies may influence subjects' behavioral and eye-movement measures in response to different segment features: segment length (from shorter to longer) and segment spatial dislocation (from right to left spatial location). Consistent spatial biases were found for both bisection responses, fixation count, and duration, as well as for the first fixation count in case of pointing task. An "extreme-left" gradient effect was suggested and discussed, with patients' behavioral and eye measures more impaired. On the contrary, the patients' performance overlaps with the controls' one in case a grasping task. The direct link of visual pointing and grasping strategy, respectively, with the two cortical ventral and dorsal pathways was adduced to explain our results.

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Aim of this study is to explore behavioral responses and eye movements of unilateral neglect patients in a virtual bisection task. Space to be bisected was included between two endpoint, segment length together with segment spatial dislocation were varied in order to test the presence of a gradient effect in both bisection behavior and visual exploration. Ten right neglect patients took part to the study, all data were then matched with those obtained from ten healthy participants. Behavioral measures (bisection and RTs) and eye-movements (fixation count and duration; first fixation count) were analyzed. Consistent spatial biases were found for bisection responses, RTs, fixation count and duration, as well as for the first fixation count. We then find a significant rightward bias in patients, i.e. increasing rightside bisection and rightward fixations when the stimuli were in the extreme left-position. Concerning merely segment length, we observed significant differences between-groups only for eye movement behavior, with increased rightward fixation count and duration in response to longer segments. In conclusion, left-to-right and longer-to-shorter continuous-gradient effects were not totally supported by our results, whereas an extreme-left gradient effect was suggested and discussed.