Figure 8.

Scalp topography of the SSVEP response. A–C, Plot of the topography for annulus orientations of 0, 20, and 45°, respectively. The on–off 15 Hz stimulation in the left visual field generated a strong response at the first harmonic in contralateral scalp regions. Within each of A–C, the rows show responses in the orientation and contrast tasks, while the first, second, and third columns show data for the attended and unattended conditions, and the difference between them. The attended and unattended conditions for each surround orientation share the same color bar, but the scale of the color bar changes with surround orientation. The difference response has its own color bar, which has the same scale for all surround orientations.