The eyes have it: Oculomotor exploration and line bisection in neglect.

In this issue of Cortex, Ishiai et al. (2006) report the eye movements of patients with left neglect during the bisection of lines of different lengths. This is the latest in a series of papers from Ishiai's group, which form an important corpus of data on the oculomotor behaviour of neglect patients during line bisection and related tasks. In this article, I argue that these data should critically constrain theoretical models of bisection errors in neglect, but that these constraints have been applied rarely in practice. First, I briefly introduce bisection behaviour in neglect and describe some of the models proposed to account for its character. I then consider the implications for these models of Ishiai and colleagues' observations. Finally, I outline a novel view of the bisection task that is more compatible with their observations.