Otolithic information is required for homing in the mouse

Area of Science:

• Neuroscience
• Sensory Systems
• Animal Behavior

Background:

• Navigation relies on both external (allothetic) and self-movement (idiothetic) cues.
• Visual landmarks guide navigation in familiar settings, but self-movement cues become critical in their absence.
• Self-movement cues include vestibular signals from semicircular canals and otolith organs.

Purpose of the Study:

• To investigate the specific contribution of otolith organ signals to spatial navigation.
• To compare navigation performance in darkness versus light conditions to isolate non-visual cue reliance.

Main Methods:

• A food-hoarding task was used with mice in both dark and light conditions.
• Mice were subjected to tilting to perturb otolithic signals.
• Navigation parameters like journey duration, circuitousness, and heading errors were measured.

Main Results:

• In darkness, tilted mice exhibited impaired homing, with longer errors and more circuitous paths compared to controls.
• In light, tilted mice showed more circuitous homeward trips but compensated for errors, indicating some visual correction.
• Otolith-dependent navigation was most critical in the absence of visual information.

Conclusions:

• Otolith organ signals are essential for accurate homing in mice.
• The vestibular system's otolith organs play a significant role in non-visual navigation.
• Environmental conditions, particularly the availability of visual landmarks, modulate the reliance on otolithic cues for navigation.