Visual Sensory System: Retinal Processing: Synaptic Transmission:
Visual Sensory System: Organisation of the visual sensory system: • Retina • Thalamus (LGN – lateral geniculate nucleus) • Primary visual cortex
Retinal Processing: Vertical information flow • Photoreceptors (rods/cones) bipolar cells retinal ganglion cells. • Retinal ganglion cells have long axons to visual cortex (CNS). • Sends a visual image to the brain. Lateral information flow • Horizontal cells mediate interactions between photoreceptors. • Amacrine cells mediate interactions between ganglion cells.
Synaptic Transmission: Photoreceptor response to light is hyperpolarisation. Retinal ganglion cells respond with APs. RGC receptive fields have centre-surround organisation (circular RFs). On-centre: centre excitatory, surround inhibitory Off-centre: centre inhibitory, surround excitatory
Retinal Processing: Vertical information flow • Photoreceptors (rods/cones) bipolar cells retinal ganglion cells. • Retinal ganglion cells have long axons to visual cortex (CNS). • Sends a visual image to the brain. Lateral information flow • Horizontal cells mediate interactions between photoreceptors. • Amacrine cells mediate interactions between ganglion cells.
Synaptic Transmission: Photoreceptor response to light is hyperpolarisation. Retinal ganglion cells respond with APs. RGC receptive fields have centre-surround organisation (circular RFs). On-centre: centre excitatory, surround inhibitory Off-centre: centre inhibitory, surround excitatory
