Mislocalization after inhibition of saccadic adaptation
Frauke Heins1,2, Markus Lappe1,3
1Institute for Psychology and Otto-Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Muenster, Muenster, Germany.
Journal of Vision
|July 14, 2022
Summary
Saccadic eye movements can adapt independently of perceived visual location. This study shows that visual perception shifts even when saccade amplitude adaptation is blocked, suggesting separate neural processes.
Area of Science:
- Neuroscience
- Ophthalmology
- Visual Perception
Background:
- Saccadic eye movements are rapid, ballistic eye movements crucial for visual exploration.
- Imprecise saccades lead to errors in target localization, triggering adaptive changes in both eye movement amplitude and perceived visual location.
- Previous research explored saccadic adaptation, but the relationship between motor adaptation and perceptual shifts remains incompletely understood.
Purpose of the Study:
- To investigate the relationship between saccadic adaptation (changes in eye movement amplitude) and changes in perceived visual location.
- To determine if perceptual shifts can occur independently of motor adaptation during saccadic adaptation.
Main Methods:
- Participants performed saccadic eye movements to visual targets under a modified adaptation paradigm designed to inhibit changes in saccade amplitude.
- A visual probe was presented near the saccade target to assess perceived visual location after the saccade.
- Saccade amplitude and perceived location were measured under different instructional conditions.
Main Results:
- Participants exhibited shifts in perceived visual location in the direction of the saccadic error, even when instructed to suppress saccade amplitude adaptation.
- Perceived location shifted and diverged from the executed saccade amplitude over time.
- Changes in perceived location occurred independently of changes in saccade amplitude, and could develop even without changes in saccade amplitude.
Conclusions:
- Saccadic adaptation involves at least two distinct plastic processes: one affecting saccade amplitude and another affecting perceived visual location.
- The observed divergence suggests that the motor command for saccades and the perceptual representation of location may adapt through separate neural pathways or at different stages of processing.
- These findings have implications for understanding sensorimotor integration and the neural basis of visual awareness.
