Previous studies reported that the cortical areas related to visual motion are activated in heading perception from optical flow. In this study, we have examined the contribution of magnocellular and parvocellular pathways to heading perception. The magnocellular pathway mainly carries motion information, and is suited to detecting motion. On the other hand, the parvocellular pathway mainly carries pattern information, and is suited to resolving fine patterns. Other previous studies reported that the magnocellular pathway can be attenuated by a red background. Therefore, if the magnocellular pathway mediates the information used in heading perception, the red background is expected to deteriorate heading perception. However, we found that the accuracy of heading perception was better with the red background than with the green background. The results indicate that the parvocellular pathway is related to heading perception.

In this paper, we first review the most common neurodegenerative diseases and mental disorders, and their effects on visual functions. Secondly, we present Psykinematix, a new Mac OS X software package dedicated to visual psychophysics. Because it does not require any programming skill, and provides an intuitive GUI that abstracts most of the inherent difficulties, this new tool provides effortless means to create and run the complex psychophysical paradigms developed by vision scientists. Finally, we discuss how Psykinematix could help clinician researchers replicate fundamental studies, and better investigate visual functions that are impaired by aging and neural dysfunctions, such as shape and motion processing.