Retrosplenial inputs drive visual representations in the medial entorhinal cortex

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Visual cues are vital for navigation and goal-directed behaviors.
• The medial entorhinal cortex (MEC) is critical for navigation and receives visual input from the retrosplenial cortex (RSC).
• Neural mechanisms underlying sensory representations in navigational circuits remain largely unknown.

Purpose of the Study:

• To investigate the neural mechanisms by which the MEC encodes visual information.
• To determine if MEC neurons respond to simple visual stimuli.
• To explore the role of retrosplenial cortex (RSC) projections in visual responses within the MEC.

Main Methods:

• High-density recordings of MEC neurons in awake, head-fixed mice.
• Presentation of simple visual stimuli.
• Optogenetic suppression of RSC afferents in the MEC.

Main Results:

• A significant proportion of MEC neurons exhibited robust responses to visual stimuli.
• Visually responsive neurons were predominantly located in layer 3 of the dorsal MEC.
• Optogenetic inhibition of RSC projections to the MEC substantially diminished visual responses.
• Functional and molecular heterogeneity was observed among visually responsive MEC neurons.

Conclusions:

• The MEC can encode simple visual cues, contributing to neural representations of location.
• Visual input from the RSC plays a significant role in mediating visual responses in the MEC.
• These findings shed light on the neural basis of visual-guided navigation.