Gaze is driven by an internal goal trajectory in a visuomotor task

Area of Science:

• Neuroscience
• Motor Control
• Human-Computer Interaction

Background:

• Gaze typically leads hand movements via saccades to visual targets.
• Recent research indicates smooth pursuit eye movements may receive non-retinal input.
• The visuomotor system's reliance on retinal slip for smooth pursuit is questioned in complex tasks.

Purpose of the Study:

• To investigate if a combination of saccades and smooth pursuit guides hand movements in complex environments.
• To test the hypothesis that internal representations of future trajectories drive eye movements.
• To determine if smooth pursuit can lead hand position, challenging the retinal slip paradigm.

Main Methods:

• A video-game task was designed for human subjects.
• Participants used thumbs to control two cursors towards a common goal.
• Obstacles were incorporated to create a complex environment requiring strategic movement.

Main Results:

• Gaze led cursor movements, featuring saccades interspersed with fixation or pursuit.
• Smooth pursuit eye movements showed no correlation with cursor position or velocity.
• The findings suggest eye movements are driven by internal goals rather than solely retinal feedback.

Conclusions:

• Both saccades and smooth pursuit are guided by internal representations of future hand trajectories.
• Eye movements in complex tasks are driven by internal goals, not just external visual cues.
• The leading gaze reflects a balance between predicting hand paths and monitoring movement execution.