PSYCH 454 Lecture Notes - Lecture 10: Optic Chiasm, Lateral Geniculate Nucleus, Retina
24 May 2018
School
Department
Course
Professor
Lecture 10: Visual Thalamus and Cortex General (1)
Visual info from the Eye transmitted along optic nerve
●Axons of ganglion cells in nasal half of retina cross @ optic chiasm to opposite tract
○Same half of visual field projects onto temporal hemiretina in one eye, and nasal
hemiretina in the other
○Each optic tract thus has axons
representing the contralateral
(opposite) half of visual field
●When light hits retina, info transmitted
down optic nerve → to optic chiasm
○@ optic chiasm: info can go
down same hemisphere OR
contralateral hemisphere
●Example: Left eye
○Each eye has temporal
hemiretina, and nasal
hemiretina
○Information about right visual hemifield (blue) will be transmitted on temporal
hemiretina
○Nasal hemiretina receives information about left visual field (pink)
●Information @ temporal hemiretina of left eye: travels downs optic nerve and continues
up optic tract on the same
○SO, information from the left eye that travels down left optic tract is all from
right hemifield
●Information @ nasal hemiretina of left eye: represents left hemifield
○Transmitted down optic nerve, CROSSES @ OPTIC CHIASM to run along optic
tract of the contralateral (opposite) hemifield
○SO, information from the left hemifield is transmitted to the right optic tract
●Follow same logic for right eye
●**any particular optic tract is representing the contralateral visual hemifield
○Left optic tract= represents right hemifield
○Right optic tract= represents left hemifield
Connections from the Retina to the lateral geniculate
nucleus (LGN)
●As information is traveling down optic tract, arrives
at thalamus to LGN
Document Summary
Lecture 10: visual thalamus and cortex general (1) Visual info from the eye transmitted along optic nerve. Axons of ganglion cells in nasal half of retina cross @ optic chiasm to opposite tract. Same half of visual field projects onto temporal hemiretina in one eye, and nasal hemiretina in the other. Each optic tract thus has axons representing the contralateral (opposite) half of visual field. When light hits retina, info transmitted down optic nerve to optic chiasm. @ optic chiasm: info can go down same hemisphere or contralateral hemisphere. Each eye has temporal hemiretina, and nasal hemiretina. Information about right visual hemifield (blue) will be transmitted on temporal hemiretina. Nasal hemiretina receives information about left visual field (pink) Information @ temporal hemiretina of left eye: travels downs optic nerve and continues up optic tract on the same. So, information from the left eye that travels down left optic tract is all from right hemifield.
