Figure-ground processing during fixational saccades in V1: indication for higher-order stability.
Ariel Gilad1, Yair Pesoa, Inbal Ayzenshtat
1Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, 52900 Israel.
Summary
Fixational saccades (FSs) cause figure-ground (FG) modulation in V1 to spatially shift, yet temporal stability allows continuous perception. This research explores how FSs impact FG segregation in the visual cortex.
Area of Science:
- Neuroscience
- Visual Perception
- Cortical Processing
Background:
- Stable perception of figures against backgrounds occurs despite constant eye movements like fixational saccades (FSs).
- Neuronal activity in primary visual cortex (V1) shows enhanced "figure" and suppressed "background" responses, but the effect of FSs on this modulation is unclear.
Purpose of the Study:
- To investigate how fixational saccades (FSs) influence figure-ground (FG) modulation in the primary visual cortex (V1).
- To understand the neural mechanisms underlying stable visual perception during eye movements.
Main Methods:
- Trained monkeys to detect a contour in noise while imaging V1 activity using voltage-sensitive dyes.
- Used eye-tracking and a 2D analytical model to map stimulus displacement onto the V1 retinotopic map following FSs.
- Computed FG modulation before and after individual FSs.
Main Results:
- FG modulation spatially "hops" within the V1 retinotopic map following FSs, mirroring retinal displacement.
- Temporally, FG modulation appeared in the new location before vanishing from the old one.
- FG modulation developed faster after an FS than after initial stimulus onset, suggesting a role in visual stability.
Conclusions:
- Despite spatial discontinuity caused by FSs, the temporal continuity of FG modulation in V1 contributes to stable figure-ground segregation.
- The rapid re-establishment of FG modulation after FSs aids in maintaining continuous visual perception.
Keywords:
contour integrationfigure-groundfixational saccadesprimary visual cortexvisual stabilityvoltage-sensitive dye imagingMore Related Videos
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