Visual Experience Is Required for the Development of Eye Movement Maps in the Mouse Superior Colliculus

Area of Science:

• Neuroscience
• Systems Neuroscience
• Developmental Neuroscience

Background:

• Topographic maps are crucial for sensory processing and motor control.
• Developmental mechanisms of motor control maps, particularly in the superior colliculus (SC), remain poorly understood.
• Understanding sensorimotor transformations is key to deciphering brain function.

Purpose of the Study:

• To map eye movement representations in the awake mouse superior colliculus (SC).
• To investigate the role of visual experience in the development of the SC's eye movement map.
• To establish a foundation for studying sensorimotor transformations in mice.

Main Methods:

• Microstimulation of the superior colliculus (SC) in awake mice to evoke eye movements.
• Systematic sampling along the anterior-posterior axis of the SC to characterize movement representations.
• Comparison of eye movement maps in normally reared mice versus mice reared in complete darkness.

Main Results:

• A topographic map for eye movements was identified in the mouse SC, with a progression from ipsiversive to contraversive movements along the anterior-posterior axis.
• This map shares global polarity with the visual (retinotopic) map, similar to primates and cats.
• Mice reared in darkness exhibited larger saccades, indicating visual experience is essential for normal eye movement map development and saccade gain tuning.

Conclusions:

• The mouse SC contains a topographic eye movement map aligned with its visual map.
• Visual experience is a critical factor in refining saccade gain and establishing normal eye movement representations in the SC.
• This study provides a basis for future research into the developmental mechanisms underlying sensorimotor integration in the SC.