Visuomotor coordination is different for different directions in three-dimensional space.

Area of Science:

• Neuroscience
• Human motor control
• Visuomotor integration

Background:

• Eye movements typically precede hand movements in visuomotor tasks.
• Vergence eye movements have distinct dynamics compared to smooth pursuit and saccades.

Purpose of the Study:

• To investigate the lead time of gaze relative to hand movements in both depth (vergence) and frontal plane (smooth pursuit and saccades).
• To analyze these lead times in both tracking and 3D tracing tasks.

Main Methods:

• Human subjects performed 3D tracking and tracing tasks.
• Gaze lead time relative to finger position was measured for depth and frontal plane components.
• The relationship between lead time and finger velocity was examined.

Main Results:

• During tracking, gaze led finger position in the frontal plane (28 ± 6 ms) but lagged in depth (95 ± 39 ms).
• During tracing, gaze led finger position in depth (151 ± 36 ms) and the frontal plane (287 ± 13 ms).
• Frontal plane lead time during tracing was inversely related to finger tangential velocity, suggesting a constant lead distance of ~2.6 cm.

Conclusions:

• Gaze lead-lag behavior relative to hand movements differs between depth and frontal plane dimensions.
• The observed inverse relationship between gaze lead time and finger velocity in the frontal plane suggests a constant spatial lead strategy during tracing.