Active vision in freely moving marmosets using head-mounted eye tracking.

Area of Science:

• Neuroscience
• Primate Vision
• Active Sensing

Background:

• Understanding primate active vision during natural navigation is limited due to head-fixed experimental setups.
• Synergistic interactions between motor actions (eyes, head, posture) and visual perception in real-world scenarios are largely unknown.

Purpose of the Study:

• To develop an innovative system for tracking eye movements in freely moving primates.
• To investigate the impact of active sensing on visual perception and gaze control in naturalistic environments.

Main Methods:

• Developed a wireless, head-mounted eye-tracking system (CEREBRO) for small mammals like marmosets.
• Utilized a segmentation artificial neural network for robust pupil tracking under variable lighting conditions.
• Recorded eye movements and correlated them with locomotion and head posture in chair-free animals.

Main Results:

• Freely moving marmosets exhibit predictable gaze behavior, higher than in head-fixed conditions.
• Gaze stabilization remains steady during locomotion despite increased eye and head motion, due to enhanced vestibular ocular reflex gain.
• Demonstrated efficient visuo-motor mechanisms enabling stable foveal vision during active exploration.

Conclusions:

• The CEREBRO system enables novel insights into primate active vision.
• Active vision in primates is characterized by dynamic visuo-motor control for stable perception during natural movement.
• Findings highlight the sophisticated mechanisms underlying primate visual navigation in complex environments.