A Cre Mouse Line for Probing Irradiance- and Direction-Encoding Retinal Networks

Area of Science:

• Neuroscience
• Vision Science
• Cell Biology

Background:

• Cell type-specific Cre driver lines are essential for dissecting complex neural circuits.
• Understanding retinal cell types and their roles in visual processing is critical.

Purpose of the Study:

• To characterize the cell types labeled by the Rbp4-Cre transgenic mouse line.
• To investigate the function of these labeled cell types in visual processing, particularly light intensity and motion detection.

Main Methods:

• Utilized the Rbp4-Cre mouse line for genetic labeling of retinal cells.
• Employed electrophysiology and tracer coupling to study cell responses and connectivity.
• Applied serial blockface electron microscopy (SBEM) for detailed circuit reconstruction.

Main Results:

• Rbp4-Cre selectively labels wide-field amacrine cells (ACs) with sustained ON responses, potentially influencing M2 intrinsically photosensitive retinal ganglion cells (ipRGCs) via gap junctions.
• Two retinal ganglion cell (RGC) types were identified: R-cells with ON responses and OFF input, and ON-OFF direction-selective (DS) RGCs (RDS).
• R-cells receive input from a novel OFF bipolar cell type and project to the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC). RDS cells project to the nucleus of the optic tract (NOT).

Conclusions:

• The Rbp4-Cre mouse line is a valuable tool for targeting and analyzing specific retinal neuronal populations.
• This line facilitates the study of ACs and RGCs involved in irradiance encoding and motion detection.
• The findings provide new insights into retinal circuit organization and the function of specific cell types in visual processing.