Abstract
moving first-order stimuli and to combined first- and second-order stimuli in order to determine whether first-order motion processing was influenced by second-order motion. Beat stimuli were made by summing two gratings of similar spatial frequency, one of which was static and the other was moving. The beat is the product of a moving sinusoidal carrier (first-order motion) and a moving low-frequency contrast envelope (second-order motion). We compared responses to moving first-order gratings alone with responses to beat patterns with first-order and second-order motion in the same direction as each other, or in opposite directions to each other in order to distinguish first-order and second-order direction-selective responses. In the majority (72%, 67/93) of cells (V1 73%, 45/62; V2 70%, 16/23; third visual complex 75%, 6/8), responses to first-order motion were significantly influenced by the addition of a second-order signal. The second-order envelope was more influential when moving in the opposite direction to the first-order stimulus, reducing first-order direction sensitivity in V1, V2, and the third visual complex. We interpret these results as showing that first-order motion processing through early visual cortex is not separate from second-order motion processing; suggesting that both motion signals are processed by the same system.
| Original language | English |
|---|---|
| Pages (from-to) | 815-824 |
| Number of pages | 10 |
| Journal | Visual neuroscience |
| Volume | 23 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2006 |
Keywords
- primate
- physiology
- V1
- luminance
- contrast
- NEW-WORLD MONKEY
- LATERAL GENICULATE-NUCLEUS
- CALLITHRIX-JACCHUS
- FIRST-ORDER
- COMPUTATIONAL MODEL
- PERIODIC PATTERNS
- STRIATE CORTEX
- COMPLEX CELLS
- BRAIN-DAMAGE
- AREA