Optic nerve is which order neuron (AIIMS Nov 2008)
Pg. 1061; Kieth L Moore (6th Ed.)
• Optic nerve is constituted by the axons of 'Ganglion cells' in the retina.
• Ganglion cells are the 'third' order neurons for the optic pathway.
• Rods /Cones (I) →Bipolar cells (II) → Ganglion cells (III) →Lateral geniculate body (IV)
• The optic nerves are paired, anterior extensions of the forebrain (diencephalon) and are therefore actually CNS ﬁber tracts formed by axons of retinal ganglion cells (Moore and Persaud, 2008).
• They are third-order neurons, with their cell bodies located in the retina.