Two visual receptor cells in the retina:
1. Cones - Colour and detail perception, mostly located in the fovea
2. Rods - vision in dim light, located in the periphery
→ Retinal ganglion cells receive input from a few cones or hundreds of rods.
Lateral Geniculate Nucleus: A relay center in the thalamus for the visual pathway. It is a
small, ovoid, ventral projection of the thalamus where the thalamus connects with the optic
nerve.
NOTE: The right optic tract (the points where the LGN is that curve round) carries
information from both left fields, and the left optic tract carries information from both right
fields.
LGN Retinotopic Map: The mapping of visual input from the retina to neurons,
particularly those neurons within the visual stream. In general, these complex maps
are referred to as second-order representations of the visual field, as opposed to
first-order (continuous) representations such as V1.
The retina-geniculate-striate system:
1. Parvocellular Pathway - Sensitive to colour and fine detail; most input comes from
cones, which it transports to the visual cortex.
, 2. Magnocellular Pathway - Most sensitive to motion; Most input comes from rods,
which it transports to the visual cortex with a different set of processing areas within
the visual cortex.
Primary visual cortex (V1): Organised in a retinotopic map; the areas in the retina
correspond to areas in the visual field.
1. Cones - Colour and detail perception, mostly located in the fovea
2. Rods - vision in dim light, located in the periphery
→ Retinal ganglion cells receive input from a few cones or hundreds of rods.
Lateral Geniculate Nucleus: A relay center in the thalamus for the visual pathway. It is a
small, ovoid, ventral projection of the thalamus where the thalamus connects with the optic
nerve.
NOTE: The right optic tract (the points where the LGN is that curve round) carries
information from both left fields, and the left optic tract carries information from both right
fields.
LGN Retinotopic Map: The mapping of visual input from the retina to neurons,
particularly those neurons within the visual stream. In general, these complex maps
are referred to as second-order representations of the visual field, as opposed to
first-order (continuous) representations such as V1.
The retina-geniculate-striate system:
1. Parvocellular Pathway - Sensitive to colour and fine detail; most input comes from
cones, which it transports to the visual cortex.
, 2. Magnocellular Pathway - Most sensitive to motion; Most input comes from rods,
which it transports to the visual cortex with a different set of processing areas within
the visual cortex.
Primary visual cortex (V1): Organised in a retinotopic map; the areas in the retina
correspond to areas in the visual field.
