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Intrasaccadic perception triggers pupillary constriction.

Mathôt S, Melmi JB, Castet E - PeerJ (2015)

Bottom Line: As a result, the retinal image was approximately stable for a brief moment during the saccade, and this gave rise to an intrasaccadic percept: A normally invisible stimulus became visible when eye velocity was maximal.Our results confirm and extend previous studies by demonstrating intrasaccadic perception using a reflexive measure (pupillometry) that does not rely on subjective report.Our results further show that intrasaccadic perception affects all stages of visual processing, from the pupillary response to visual awareness.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Psychologie Cognitive, UMR 7290, Aix-Marseille University/CNRS , Marseille , France.

ABSTRACT
It is commonly believed that vision is impaired during saccadic eye movements. However, here we report that some visual stimuli are clearly visible during saccades, and trigger a constriction of the eye's pupil. Participants viewed sinusoid gratings that changed polarity 150 times per second (every 6.67 ms). At this rate of flicker, the gratings were perceived as homogeneous surfaces while participants fixated. However, the flickering gratings contained ambiguous motion: rightward and leftward motion for vertical gratings; upward and downward motion for horizontal gratings. When participants made a saccade perpendicular to the gratings' orientation (e.g., a leftward saccade for a vertical grating), the eye's peak velocity matched the gratings' motion. As a result, the retinal image was approximately stable for a brief moment during the saccade, and this gave rise to an intrasaccadic percept: A normally invisible stimulus became visible when eye velocity was maximal. Our results confirm and extend previous studies by demonstrating intrasaccadic perception using a reflexive measure (pupillometry) that does not rely on subjective report. Our results further show that intrasaccadic perception affects all stages of visual processing, from the pupillary response to visual awareness.

No MeSH data available.


Related in: MedlinePlus

Results for an optimal subset of vertical saccades.Analysis of a subset of vertical-saccade trials on which orthogonal velocity was low and peak saccade velocity was close to optimal. Pupil size is plotted over time, locked to the mid-saccade point. There was a more pronounced constriction in the Intrasaccadic Percept Condition than in the No-Percept Condition. Error bands indicate the standard error. Gray shading indicates a reliable effect of Condition.
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fig-7: Results for an optimal subset of vertical saccades.Analysis of a subset of vertical-saccade trials on which orthogonal velocity was low and peak saccade velocity was close to optimal. Pupil size is plotted over time, locked to the mid-saccade point. There was a more pronounced constriction in the Intrasaccadic Percept Condition than in the No-Percept Condition. Error bands indicate the standard error. Gray shading indicates a reliable effect of Condition.

Mentions: Next, using vertical saccades from this subset of data, selected as described above, we performed the same analysis as before. Based on an LME with Condition as fixed effect and pupil size as dependent measure, we now also observed a reliable Condition effect for vertical saccades (Fig. 7). Therefore, it is likely that the Condition effect for vertical saccades was reduced by variability in peak velocity, and pronounced curvature.


Intrasaccadic perception triggers pupillary constriction.

Mathôt S, Melmi JB, Castet E - PeerJ (2015)

Results for an optimal subset of vertical saccades.Analysis of a subset of vertical-saccade trials on which orthogonal velocity was low and peak saccade velocity was close to optimal. Pupil size is plotted over time, locked to the mid-saccade point. There was a more pronounced constriction in the Intrasaccadic Percept Condition than in the No-Percept Condition. Error bands indicate the standard error. Gray shading indicates a reliable effect of Condition.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4558071&req=5

fig-7: Results for an optimal subset of vertical saccades.Analysis of a subset of vertical-saccade trials on which orthogonal velocity was low and peak saccade velocity was close to optimal. Pupil size is plotted over time, locked to the mid-saccade point. There was a more pronounced constriction in the Intrasaccadic Percept Condition than in the No-Percept Condition. Error bands indicate the standard error. Gray shading indicates a reliable effect of Condition.
Mentions: Next, using vertical saccades from this subset of data, selected as described above, we performed the same analysis as before. Based on an LME with Condition as fixed effect and pupil size as dependent measure, we now also observed a reliable Condition effect for vertical saccades (Fig. 7). Therefore, it is likely that the Condition effect for vertical saccades was reduced by variability in peak velocity, and pronounced curvature.

Bottom Line: As a result, the retinal image was approximately stable for a brief moment during the saccade, and this gave rise to an intrasaccadic percept: A normally invisible stimulus became visible when eye velocity was maximal.Our results confirm and extend previous studies by demonstrating intrasaccadic perception using a reflexive measure (pupillometry) that does not rely on subjective report.Our results further show that intrasaccadic perception affects all stages of visual processing, from the pupillary response to visual awareness.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Psychologie Cognitive, UMR 7290, Aix-Marseille University/CNRS , Marseille , France.

ABSTRACT
It is commonly believed that vision is impaired during saccadic eye movements. However, here we report that some visual stimuli are clearly visible during saccades, and trigger a constriction of the eye's pupil. Participants viewed sinusoid gratings that changed polarity 150 times per second (every 6.67 ms). At this rate of flicker, the gratings were perceived as homogeneous surfaces while participants fixated. However, the flickering gratings contained ambiguous motion: rightward and leftward motion for vertical gratings; upward and downward motion for horizontal gratings. When participants made a saccade perpendicular to the gratings' orientation (e.g., a leftward saccade for a vertical grating), the eye's peak velocity matched the gratings' motion. As a result, the retinal image was approximately stable for a brief moment during the saccade, and this gave rise to an intrasaccadic percept: A normally invisible stimulus became visible when eye velocity was maximal. Our results confirm and extend previous studies by demonstrating intrasaccadic perception using a reflexive measure (pupillometry) that does not rely on subjective report. Our results further show that intrasaccadic perception affects all stages of visual processing, from the pupillary response to visual awareness.

No MeSH data available.


Related in: MedlinePlus