The receptor on the on centre and off centre bipolar cell are AMPA receptors

When light hits the centre field there is a decrease in glutamate release so increased activity in the on centre retinal ganglion cell and decrease activity in the off centre retinal ganglion cell

The mechanism makes vision a lot clearer and gives contrast

When light hits the surround field there is an increase in glutamate release resulting in decreased activity of the on centre retinal ganglion cell and increase activity in the off centre retinal ganglion cell

Glutamate is released by rods and cones onto bipolar cells

Glutamate release causes inhibition of the on centre bipolar cell and excitation of the off centre bi polar cell

V2/V3/V4

V1/V2/V3

V2/V3

V3

V3/V4

V1

Features (parvocellular layer)

Visuospatial awareness (mangocellular layer)

Visual reflexes

Receiving input from the optic nerve

Receiving contralateral input