Sensory Cues Modulate Smooth Pursuit and Active Sensing Movements

Area of Science:

• Ethology
• Neuroethology
• Sensory Ecology

Background:

• Animals use movement to control sensory information intake.
• Weakly electric fish navigate using visual and electrosensory cues, employing specific movements to track refuges.

Purpose of the Study:

• To investigate the relationship between sensory cues and the production of linear (smooth pursuit) and nonlinear (active sensing) movements in weakly electric fish during refuge tracking.
• To identify and categorize nonlinear movements used by fish for active sensing.

Main Methods:

• Altering visual and electrosensory cues by changing refuge length, structure, and light conditions.
• Measuring fish fore-aft movements during refuge tracking experiments.
• Categorizing nonlinear movements into scanning, wiggle, drift, and reset.

Main Results:

• Tracking performance was better in shorter refuges (<1 body length) than longer ones (>1.5 body lengths).
• Nonlinear active sensing movements were modulated by light, increasing with longer refuges and fewer features.
• Fish shifted from smooth pursuit to scanning in darkness, and used drifts/resets in longer refuges to prevent exiting.

Conclusions:

• Weakly electric fish employ distinct linear and nonlinear movement strategies for refuge tracking, adapting to environmental conditions.
• Nonlinear movements serve as an alternative strategy, particularly in challenging conditions like long refuges or darkness.
• Sensory cues, including light and refuge characteristics, significantly influence the type and magnitude of movements used for navigation.