Internally generated smooth eye movement: its dynamic characteristics and role in randomised and predictable pursuit

Area of Science:

• Neuroscience
• Ophthalmology
• Motor Control

Background:

• Smooth eye movements were initially studied for prediction.
• Internal (extra-retinal) mechanisms are now understood to influence pursuit responses.
• These internally generated movements have distinct characteristics compared to visually driven ones.

Purpose of the Study:

• To investigate the role of internally generated smooth eye movements in both predictable and randomized pursuit responses.
• To provide evidence for internally generated movements in randomized step-ramp responses.
• To elucidate the conditions and mechanisms underlying internally generated eye movements.

Main Methods:

• Analysis of smooth eye movement trajectories.
• Evoking internally generated responses using regularly repeated motion stimuli or temporal cues.
• Utilizing target extinction to reveal internally generated components in randomized responses.

Main Results:

• Internally generated responses exhibit slow initial acceleration but can reach high velocities.
• These movements contribute to the extra-retinal component of randomized step-ramp responses.
• Expectation of future target motion is crucial for initiating these responses.

Conclusions:

• Internally generated smooth eye movements are fundamental to both predictable and randomized pursuit.
• These movements rely on the rapid acquisition and storage of velocity and timing information.
• Understanding these internal mechanisms offers insights into eye movement control and prediction.