Abstract
Background. It is currently believed that the cortical deficit associated with amblyopic vision extends beyond striate cortex into extrastriate areas. Biological motion perception has been localized to a specific extrastriate cortical region (STS) which receives input from both dorsal and ventral visual processing streams. We used a variety of biological motion perception tasks to assess the function of this extrastriate region in amblyopia.
Methods. Amblyopic observers viewed biological motion stimuli with either their amblyopic or fellow fixing eye. A range of tasks were used to better characterize the ability of amblyopic eyes to perceive biological motion. Detection of a point light walker was measured using both scrambled walker masks and linear motion masks to modulate task difficulty. Walking direction discrimination was also measured using both scrambled walkers, which provided only motion information, and unscrambled walkers. These stimuli were embedded in linear dot masks of various densities.
Results. Amblyopic eyes showed a deficit in biological motion detection. Amblyopic eyes did not however show a similar deficit for walking direction discrimination and could perform this task with both unscrambled and scrambled walkers.
Conclusion. Amblyopic eyes are impaired at segregating a point light walker from a noise mask. However the ability to extract information from the biological motion of the walker dots showed little impairment.
supported by CIHR grant #MT18-108 to RFH