Implicit motion perception in schizotypy and schizophrenia: a Representational Momentum study.
BACKGROUND
Human observers exhibit a distortion in recognition memory for pictures that imply motion because of an automatic mental process, which extrapolates along the implied trajectory of the picture. This is known as Representational Momentum (RM). Converging evidence (functional imaging; magnetic stimulation studies) suggests activity in area MT/MST (V5) is necessary for RM to occur. Patients with schizophrenia and healthy schizotypic individuals have been found to show motion perception deficits and abnormal eye-tracking (both indicative of abnormal functioning within brain area V5), therefore it was hypothesised that these individuals would show a reduced or absent RM effect.


METHODS
Fifty healthy individuals and seven patients diagnosed with schizophrenia undertook a task previously found to elicit the RM effect.


RESULTS
Although the size of the RM effect was not significantly different between either low and high schizotypes or low schizotypes and patients, there was a trend (in the opposite direction to that predicted) for the patients with schizophrenia and the high schizotypes to exhibit a larger RM effect.


CONCLUSIONS
The findings are discussed in terms of functional connectivity between frontal areas and V5, and of schizophrenia involving a failure to inhibit automatic processes.
Department of Optometry & Neuroscience, UMIST, Manchester, UK. c.jarrett@student.umist.ac.uk
Christian B
CB
Jarrett
Mary
M
Phillips
Andrew
A
Parker
Carl
C
Senior