Central Visual Pathways

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The visual system | Main Anatomy Index | The cerebellum

Last updated 1 April 2006

Central Visual Pathways

Ganglion cell axons --> optic nerve --> optic chiasm (partial decussation) --> optic tract --> lateral geniculate nucleus (thalamic relay nucleus for vision) --> internal capsule --> corona radiata --> primary visual cortex (calcarine sulcus)

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Optic Nerve


Optic Chiasm


Optic Tract

  1. The fibres arising in the temporal retina of the ipsilateral eye;
  2. And the fibres of the nasal retina of the contralateral eye.
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Lateral Geniculate Nucleus

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Optic radiation


Retinotopic Organisation of the Optic Radiation

Visual Field Location of Fibres
Inferior Most superior
Superior Loop farthest into the temporal lobe
Macula fibres Broad middle area
Visual Field Part of Visual Cortex
Inferior Above calcarine sulcus
Superior Below calcarine sulcus
Macula More posteriorly
Peripheral More anteriorly
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Superior Colliculus

  1. The reticular formation;
  2. The inferior colliculus;
  3. The cervical spinal cord (the tectospinal tract).


Retinohypothalamic Fibres

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Processing of Visual Information


Visual Reflexes

Pupillary Light Reflex

Optic tract axons (afferent limb) --> superior brachium --> pretectal area (terminate) --> Edinger-Westphal nucleus (bilaterally) --> CN III (as preganglionic parasympathetic fibres) --> ciliary ganglion --> postganglionic parasympathetic fibres (efferent limb) --> sphincter pupillae muscle


The Swinging Flashlight Test


Near Reflex (accommodation reflex)

  1. Convergence of eyes, so that the image of the object falls on both foveae;
  2. Contraction of the ciliary muscle and a resultant thickening of the lens, so the image of the object is in focus on the retina;
  3. And pupillary constriction, which improves the optical performance of the eye by reducing certain types of aberration and by increasing its depth of focus.

Normal visual pathway --> primary visual cortex --> visual association cortex --> superior colliculus and/or pretectal area --> oculomotor nucleus (medial rectus) and Edinger-Westphal nucleus (preganglionic parasympathetic motor neurons)

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Michael Tam (c) 1998