The effects of fixational eye movements on population responses in V1. Keynote at the 20th European Conference on Eye Movements in Alicante, September 22, 2019

Area of Science:

• Neuroscience
• Visual Neuroscience
• Computational Neuroscience

Background:

• The precise impact of microsaccades (MSs) on neural activity in the visual cortex remains unclear.
• Understanding these effects is crucial for comprehending visual processing during fixation.

Purpose of the Study:

• To investigate the spatiotemporal patterns of neuronal responses to MSs in early visual cortices.
• To elucidate how MSs influence neural activity and visual perception.

Main Methods:

• Voltage-sensitive dye imaging was employed in behaving monkeys to record neural activity.
• Analysis focused on neuronal responses in V1 correlated with MS parameters.

Main Results:

• Microsaccades induce a continuous "visual instability," causing neuronal activity to "hop" within the retinotopic map.
• Neuronal modulations include suppression followed by enhancement and increased synchronization.
• This instability affects figure-ground segregation, potentially speeding up its development post-saccade.

Conclusions:

• Microsaccades dynamically alter neural processing in the visual cortex.
• Suppressed activity may relate to suppressed perception, while enhancement could aid new information processing.
• MS-induced instability is a key factor in visual perception mechanisms.