Textbook Notes (362,837)
Canada (158,073)
Neuroscience (289)
NROC64H3 (81)
Chapter 10

chapter 10

8 Pages
Unlock Document

University of Toronto Scarborough
Matthias Niemeier

INTRODUCTION The pathway serving conscious visual perception includes the lateral geniculate nucleus LGNInformation is funnelled through this of the thalamus and the primary visual cortexgeniculocortical pathway and is processed in parallel by neurons specialized for the analysis of different stimulus attribute The striate cortex then feeds this information to different extrastriate cortical areas in the temporal and parietal lobes THE RETINOFUGAL PROJECTIONy The neural pathway leaving the eyes starting with the optic nerveThe Optic Nerve Optic Chiasm and Optic Tract y The ganglion cell axons leaving the retina pass through three structures before forming synapses in the brain stem see Fig 102 o Optic nerve o Optic chiasm o Optic tract y The optic nerves exit the left and right eyes at the optic disks and combine to form the optic chiasm Here the axons originating in the nasal retinas cross from one side to the other and this is called decussation ie the crossing of a fiber bundle from one side of the brain to the other In this case the decussation is partial and following this crossing the axons of the retinofugal projections form the optic tractsRight and Left Visual Hemifields y Left visual hemifield objects appearing to the left of the midline y Right visual hemifield objects appearing to the right of the midline see Fig 103 The central portion of both visual hemifields is viewed by both retinas and this region of space is the binocular visual field Objects in the binocular region of the left visual hemifield will be imaged on the nasal retina of the left eye and on the temporal region of the right eye y Rule of Thumb optic nerve fibers cross in the optic chiasm so that the left visual hemifield is viewed by the right hemisphere and the right visual hemifield is viewed by the left hemisphereTargets of the Optic Tract A small number of optic tract axons peel off to form synaptic connections with cells in the hypothalamus and another 10 innervate the midbrain Most innervate the lateral geniculate nucleus LGN of the dorsal thalamus and these neurons give rise to axons projecting to the primary visual cortex This projection is called the optic radiation Lesions in these areas will cause blindnessSee Fig 105 y A transaction of the left optic nerve would lead to blindness at the left eye only y A transaction of the left optic tract would lead to blindness at the right visual field
More Less

Related notes for NROC64H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.