Abstract
When presented with a daisy lacking the left-side petals, healthy subjects swiftly find out the portion of its incompleteness. When they find a daisy with its left side hidden by a wall, they feel as such but not as a right half daisy. Patients with left unilateral spatial neglect following a right hemisphere stroke would copy only the right side of a daisy and fail to be aware of the incompleteness on the left side. They never state that the model figure of a daisy is a right half one or that its left side is outside their vision. For healthy subjects, there is no apparent right-left bias of spatial attention in such a narrow spatial frame where a figure of a daisy is presented. However, patients with left neglect have a rightward bias of spatial attention for the body-centered outside space as well as the object/stimulus-centered frame of space. The unattended space is a “vacancy” that is never felt as lost or where no conscious awareness of absence arises. By contrast, recognition of a seen object took place on the basis of the visual information about its attended right-side. The present paper try approach and understand the visual world of patients with left neglect focusing on the gap between the spatial and object cognitions.
