Naming rotated pictures and the riddle of object-centred neglect.

In this study eight patients with left neglect were asked to name chimerical pictures of objects and animals with different spatial orientation: standard upright position, rotated 180 degrees, rotated 90 degrees to the right, and rotated 90 degrees to the left. All patients showed the typical pattern of egocentric neglect. They omitted the left part of the normally upright pictures and the right part of the inverted stimuli, now falling in the left space. When the pictures were tilted 90 degrees to the right, they reported the two component objects with the same level of accuracy. However, at variance with egocentric neglect, when the chimerical pictures were rotated 90 degrees to the left, the patients omitted the left half of the stimulus more often than the right half. We propose that since in the latter condition the less informative lower part of the pictures was available in the non-neglected space, the patients mentally rotated the perceived stimulus and aligned it with its upright orientation before naming its component parts. In our interpretation, the mental orientation and normalisation of rotated stimuli might underlie all the reported evidence of object-centred neglect for non-orthographic stimuli.