BOLD Signal in Both Ipsilateral and Contralateral Retinotopic Cortex Modulates with Perceptual Fading
Po‐jang Hsieh, Peter Ulric Tse
PLoS One March 10, 2010 DOI: 10.1371/journal.pone.0009638 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Measures | Blood oxygen-level dependent (BOLD) signal, microsaccade rate |
| Citations | 4 |
| Key findings | BOLD signal in V1, V2v, and V3v decreased when a fixated disk subjectively disappeared and increased when it reappeared, occurring both ipsilaterally and contralaterally to the fading figure. Microsaccade rate rose before and after transitions from not seeing to seeing and decreased before transitions from seeing to not seeing. The authors suggest these BOLD changes could be driven by a global process across visual cortex or by a confounding factor such as microsaccade rate. |
Abstract
UNLABELLED: Under conditions of visual fixation, perceptual fading occurs when a stationary object, though present in the world and continually casting light upon the retina, vanishes from visual consciousness. The neural correlates of the consciousness of such an object will presumably modulate in activity with the onset and cessation of perceptual fading.
Method: In order to localize the neural correlates of perceptual fading, a green disk that had been individually set to be equiluminant with the orange background, was presented in one of the four visual quadrants; Subjects indicated with a button press whether or not the disk was subjectively visible as it perceptually faded in and out.
Results: Blood oxygen-level dependent (BOLD) signal in V1 and ventral retinotopic areas V2v and V3v decreases when the disk subjectively disappears, and increases when it subjectively reappears. This effect occurs in early visual areas both ipsilaterally and contralaterally to the fading figure. That is, it occurs regardless of whether the fading stimulus is presented inside or outside of the corresponding portion of visual field. In addition, we find that the microsaccade rate rises before and after perceptual transitions from not seeing to seeing the disk, and decreases before perceptual transitions from seeing to not seeing the disk. These BOLD signal changes could be driven by a global process that operates across contralateral and ipsilateral visual cortex or by a confounding factor, such as microsaccade rate.