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Microsaccade rate varies with subjective visibility during motion-induced blindness.

Hsieh PJ, Tse PU - PLoS ONE (2009)

Bottom Line: Here we report the first psychophysical data concerning effects of microsaccade/eyeblink rate upon perceptual switches during MIB.We find that the rate of microsaccades/eyeblink rises before and after perceptual transitions from not seeing to seeing the dot, and decreases before perceptual transitions from seeing it to not seeing it.In addition, event-related fMRI data reveal that, when a dot subjectively reappears during MIB, the blood oxygen-level dependent (BOLD) signal increases in V1v and V2v and decreases in contralateral hMT+.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychological and Brain Sciences, Moore Hall, Dartmouth College, Hanover, New Hampshire, United States of America. pjh@mit.edu

ABSTRACT
Motion-induced blindness (MIB) occurs when a dot embedded in a motion field subjectively vanishes. Here we report the first psychophysical data concerning effects of microsaccade/eyeblink rate upon perceptual switches during MIB. We find that the rate of microsaccades/eyeblink rises before and after perceptual transitions from not seeing to seeing the dot, and decreases before perceptual transitions from seeing it to not seeing it. In addition, event-related fMRI data reveal that, when a dot subjectively reappears during MIB, the blood oxygen-level dependent (BOLD) signal increases in V1v and V2v and decreases in contralateral hMT+. These BOLD signal changes observed upon perceptual state changes in MIB could be driven by the change of perceptual states and/or a confounding factor, such as the microsaccade/eyeblink rate.

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The differences of BOLD signal timecourses (TR = 1.6 seconds) upon perceptual switches in V3A/B, V4v, and hMT+.(a) The BOLD signal modulates weakly in V3A/B or V4v. (b) The BOLD signal modulates with the percept in contralateral hMT+, in a manner largely opposite that of V1v and V2v. In particular, BOLD signal decreases upon subjective disappearance of the dot in hMT+, but increases in V1 and V2.
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pone-0005163-g006: The differences of BOLD signal timecourses (TR = 1.6 seconds) upon perceptual switches in V3A/B, V4v, and hMT+.(a) The BOLD signal modulates weakly in V3A/B or V4v. (b) The BOLD signal modulates with the percept in contralateral hMT+, in a manner largely opposite that of V1v and V2v. In particular, BOLD signal decreases upon subjective disappearance of the dot in hMT+, but increases in V1 and V2.

Mentions: Figure 5 shows the average timecourse data for the ‘see’ and ‘no see’ states. An asterisk above or below a data point, in the color of that data point indicates that it differs significantly (p<0.05) from TR0 (the BOLD signal at the time of a perceptual state change set to zero). Our results show that, in general, early visual areas have a stronger BOLD activation after a perceptual switch (Figure 5) such that signal intensity rises after perceptual transitions from ‘no see’ to ‘see’ (pink) for the case where the dot was in fact present in the corresponding contralateral quadrant. Surprisingly, BOLD signal deviations reached significance not only when the target was located within these ROI's contralateral ‘within’ quadrant (as opposed to the contralateral quadrant where the dot was not present), which might have been expected, but also when the target was located ipsilaterally to these ROIs, which was far from expected. BOLD signal modulates relatively more weakly with perceptual state in contralateral or ipsilateral V3v, V3d (Figure 5), V3A or V4v (Figure 6a). In area hMT+ (Figure 6b), the BOLD signal decreases upon transition to ‘see’ when the target dot was presented contralaterally, which is opposite the BOLD response pattern evident in areas V1v and V2v.


Microsaccade rate varies with subjective visibility during motion-induced blindness.

Hsieh PJ, Tse PU - PLoS ONE (2009)

The differences of BOLD signal timecourses (TR = 1.6 seconds) upon perceptual switches in V3A/B, V4v, and hMT+.(a) The BOLD signal modulates weakly in V3A/B or V4v. (b) The BOLD signal modulates with the percept in contralateral hMT+, in a manner largely opposite that of V1v and V2v. In particular, BOLD signal decreases upon subjective disappearance of the dot in hMT+, but increases in V1 and V2.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2664481&req=5

pone-0005163-g006: The differences of BOLD signal timecourses (TR = 1.6 seconds) upon perceptual switches in V3A/B, V4v, and hMT+.(a) The BOLD signal modulates weakly in V3A/B or V4v. (b) The BOLD signal modulates with the percept in contralateral hMT+, in a manner largely opposite that of V1v and V2v. In particular, BOLD signal decreases upon subjective disappearance of the dot in hMT+, but increases in V1 and V2.
Mentions: Figure 5 shows the average timecourse data for the ‘see’ and ‘no see’ states. An asterisk above or below a data point, in the color of that data point indicates that it differs significantly (p<0.05) from TR0 (the BOLD signal at the time of a perceptual state change set to zero). Our results show that, in general, early visual areas have a stronger BOLD activation after a perceptual switch (Figure 5) such that signal intensity rises after perceptual transitions from ‘no see’ to ‘see’ (pink) for the case where the dot was in fact present in the corresponding contralateral quadrant. Surprisingly, BOLD signal deviations reached significance not only when the target was located within these ROI's contralateral ‘within’ quadrant (as opposed to the contralateral quadrant where the dot was not present), which might have been expected, but also when the target was located ipsilaterally to these ROIs, which was far from expected. BOLD signal modulates relatively more weakly with perceptual state in contralateral or ipsilateral V3v, V3d (Figure 5), V3A or V4v (Figure 6a). In area hMT+ (Figure 6b), the BOLD signal decreases upon transition to ‘see’ when the target dot was presented contralaterally, which is opposite the BOLD response pattern evident in areas V1v and V2v.

Bottom Line: Here we report the first psychophysical data concerning effects of microsaccade/eyeblink rate upon perceptual switches during MIB.We find that the rate of microsaccades/eyeblink rises before and after perceptual transitions from not seeing to seeing the dot, and decreases before perceptual transitions from seeing it to not seeing it.In addition, event-related fMRI data reveal that, when a dot subjectively reappears during MIB, the blood oxygen-level dependent (BOLD) signal increases in V1v and V2v and decreases in contralateral hMT+.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychological and Brain Sciences, Moore Hall, Dartmouth College, Hanover, New Hampshire, United States of America. pjh@mit.edu

ABSTRACT
Motion-induced blindness (MIB) occurs when a dot embedded in a motion field subjectively vanishes. Here we report the first psychophysical data concerning effects of microsaccade/eyeblink rate upon perceptual switches during MIB. We find that the rate of microsaccades/eyeblink rises before and after perceptual transitions from not seeing to seeing the dot, and decreases before perceptual transitions from seeing it to not seeing it. In addition, event-related fMRI data reveal that, when a dot subjectively reappears during MIB, the blood oxygen-level dependent (BOLD) signal increases in V1v and V2v and decreases in contralateral hMT+. These BOLD signal changes observed upon perceptual state changes in MIB could be driven by the change of perceptual states and/or a confounding factor, such as the microsaccade/eyeblink rate.

Show MeSH
Related in: MedlinePlus