Figure 5.

SSVEPs to higher level stimuli contain both figure-segmentation-related (odd harmonic) and nonfigure-related (even harmonic) responses. (a) Test condition: A spatially segmented display created by texture discontinuity cues was alternated with a spatially uniform field at 1 Hz. Control condition: The same local stimulus change, a 180° rotation of the texture within the disk region, does not change the segmentation state because the texture inside the disk never matches that of the background. (b) Top panel: The response spectrum from the test condition contains both odd and even harmonics. Bottom panel: The response spectrum from the control condition contains only even harmonics. (c) Top panel: The cycle average time course for the test condition shows larger responses to onset of the segmented image (at 500 ms) than to offset (0 ms). Bottom panel: Control-condition responses are equivalent after image transient at 500 and 0 ms.