The critical speed for motion streak processing in early visual cortex

Motion-defined contour processing in the early visual cortex.

From our daily experience, it is very clear that relative motion cues can contribute to correctly identifying object boundaries and perceiving depth. Motion-defined contours are not only generated by the motion of objects in a scene but also by the movement of an observer's head and body (motion parallax). However, the neural mechanism involved in detecting these contours is still unknown. To e...

Speed in early visual processing

Motion Processing in Human Visual Cortex

Acknowledgments. The authors thank David Heeger, Alex Huk, Nestor Matthews and Mark Nawrot for comments on sections of this chapter. David Bloom helped greatly with manuscript formatting and references. During preparation of this chapter RB and EG were supported by research grants from the National Institutes of Health (EY07760) and the National Science Foundation (BCS0121962) and by a Core Gra...

Numerosity processing in early visual cortex

While parietal cortex is thought to be critical for representing numerical magnitudes, we recently reported an event-related potential (ERP) study demonstrating selective neural sensitivity to numerosity over midline occipital sites very early in the time course, suggesting the involvement of early visual cortex in numerosity processing. However, which specific brain area underlies such early a...

Critical spatial frequencies for illusory contour processing in early visual cortex.

Single neurons in primate V2 and cat A18 exhibit identical orientation tuning for sinewave grating and illusory contour stimuli. This cue invariance is also manifested in similar orientation maps to these stimuli, but in V1/A17 the illusory contour maps appear reversed. We hypothesized that this map reversal depends upon the spatial frequencies of the inducers in the illusory contours, relative...