A. Anzai et al., Joint-encoding of motion and depth by visual cortical neurons: neural basis of the Pulfrich effect, NAT NEUROSC, 4(5), 2001, pp. 513-518
Motion and stereoscopic depth are fundamental parameters of the structural
analysis of visual scenes. Because they are defined by a difference in obje
ct position, either over time or across the eyes, a common neural machinery
may be used for encoding these attributes. To examine this idea, we analyz
ed responses of binocular complex cells in the cat striate cortex to stimul
i of various intra- and interocular spatial and temporal shifts. We found t
hat most neurons exhibit space-time-oriented response profiles in both mono
cular and binocular domains. This indicates that these neurons encode motio
n and depth jointly, and it explains phenomena such as the Pulfrich effect.
We also found that the relationship between neuronal tuning of motion and
depth conforms to that predicted by the use of motion parallax as a depth c
ue. These results demonstrate a joint-encoding of motion and depth at an ea
rly cortical stage.