, 2008, Saevarsson et al., 2009 and Schindler et al., 2009) and despite the improvement shown in the chimeric non-face object task (Sarri et al., 2006). Specifically, we sought to determine whether the apparently null effect of prism adaptation on the chimeric face task (Ferber et al., 2003 and Sarri et al., 2006) could be due to the nature of the stimuli or the nature of the task used. selleck chemicals To address these issues, the effect (or lack thereof) of prism adaptation on the chimeric face expression judgement task was compared here with the impact of prisms on a logically similar lateral preference task but now employing non-face, non-emotional stimuli (greyscale gradients); and with the impact
on a different task using the same face stimuli again,
but now providing a more direct or ‘explicit’ measure HDAC inhibitor of contralesional awareness, having a right versus wrong answer, and requiring no emotional judgement on the stimuli, but simply a judgment of whether they were chimeric or not. The results replicated those of Sarri et al. (2006) and confirmed previous findings (Ferber et al., 2003) in a new sample of eleven patients, showing persisting, unaltered ipsilesional biases after prism adaptation in the chimeric face lateral preference task, which required forced-choice spatial preference judgements of emotional expression. A strong initial preference bias was found in ten out of eleven patients tested here (all except AK) pre-adaptation, who based their emotional expression judgements predominantly on the right side of the chimeric face stimuli. As also suggested by previous findings (Ferber et al., 2003 and Sarri et al., 2006), this lateral bias remained totally unaffected in all patients (even the atypical case of AK also showed no prism impact), after a successful adaptation period to rightward deviating prisms. Moreover, the lack of any prism impact on the face expression lateral preference task contrasted with the clear and significant prism impact on open-loop pointing, and also with the beneficial impact on subjective straight-ahead and line bisection, for which neglect in our patients
was clearly reduced by the prism intervention. Thus the lack of a prism impact on next the lateral preference face task cannot be due to any overall ineffectiveness of our prism manipulation per se. Importantly, we also found here an analogous pattern for a similar but non-face, non-emotional lateral preference task requiring darkness judgements for pairs of greyscale gradient rectangles. This task is logically similar in nature to the chimeric face lateral preference task, in also being an ‘implicit’ or indirect measure of perceptual awareness, having no right or wrong answer, while measuring a preferential choice between identical but left-right mirror-reversed stimuli. But they key point for present purposes is that the greyscale task utilized non-face, non-emotional stimuli. In accord with Mattingley et al.