Certain retinal horizontal cells have a center-surround antagonistic organization

Area of Science:

• Neuroscience
• Retinal Physiology
• Visual Processing

Background:

• Retinal horizontal cells (HCs) are known to create broad receptive fields, crucial for antagonistic surround responses in bipolar cells.
• These surround responses in bipolar cells are vital for enhancing visual contrast.

Purpose of the Study:

• To investigate whether specific retinal horizontal cells possess center-surround antagonistic receptive fields.
• To characterize the receptive field properties of yellow/red, blue-type horizontal cells (Y/RB HCs) in the carp retina.

Main Methods:

• Conventional intracellular electrophysiology was used to measure the receptive fields of Y/RB HCs in carp retina.
• Responses to slit light stimuli of varying wavelengths and positions were analyzed.

Main Results:

• Y/RB HCs demonstrated center-surround antagonistic receptive fields, with center light (500 nm) causing hyperpolarization and peripheral light causing depolarization.
• Depolarizing responses to 600 nm light had a larger length constant (1.22 mm) than hyperpolarizing responses to 500 nm light (0.61 mm).
• GABA and picrotoxin application suggested GABAergic signaling modulates these antagonistic mechanisms.

Conclusions:

• Depolarizing responses of Y/RB HCs possess a larger receptive field than their hyperpolarizing responses.
• The response polarity of Y/RB HCs may regulate the width of the surround receptive field in bipolar cells, impacting visual contrast detection.