Information Pathways

Question 1

Info Pathways

Answer 1

While paths have stops in common (e.g. LGN, V1, V2) information sub-pathways remain largely independent

Question 2

Ventral Stream

also called?

specialized for?

integrated with?

begins at?

Answer 2

(“Parvocellular Pathway”, “Temporal Pathway”, “Who/What Pathway”) For identifying stimuli

• Specialized for color & detail (shape, texture);
• Integrated with Language centers for naming identified objects
• Begins at Cones in and near Fovea

Question 3

Ventral Stream Begins at Cones in and near Fovea

mostly?

RFs?

basic pathway?

which layers?

ganglions?

Answer 3

=> Mostly Parvocellular (small) Ganglions (called “X Ganglions”), w/small RFs, give sustained response
=> Basic pathway (with sub-paths): Top 4 layers of LGN (Lateral Geniculate Nucleus) of Thalamus
=>V1(“Striate Cortex”)=>V2=>V3=>V4 all in Occipital lobe =>IT (in Inferior Temporal Cortex)

Question 4

Parvocellular

Answer 4

small

Question 5

Dorsal Stream

also called?

integrated with?

begins at?

Answer 5

(“Magnocellular Pathway”, “Parietal Pathway”, “Where/How Pathway”)

For visio-spatial mapping

• For detecting motion, locating objects, navigating & manipulating environment including gross outline
• Integrated w/ Somatosensory info from antero-dorsal Parietal and with Premotor & Motor Cortex from Frontal
• Begins at Rods & Cones in periphery of Retina

Question 6

Dorsal Stream begins at Rods and Cones in periphery of Retina

mostly?

ganglions?

RFs?

Answer 6

=> Mostly Magnocellular (large) Ganglions (called “Y Ganglions”), large RFs, transient response
=> Some of these to Superior Colliculus of Midbrain (e.g. for “Blindsight”), then on to LGN
=> Most Y Ganglions go directly to (bottom 2 layers of) LGN; All=>V1=>V2=>MT (Medial Temporal Cortex)
=>MST (Medial Superior Temporal Cortex) => <= Posterior Parietal Cortex

Question 7

Mostly Y ganglions go directly to…

Answer 7

… LGN