Chapter contents
Overview
Sensory transduction
Central course
Primary visual cortex
Retinal deficits
Optic nerve damage
Chiasm damage
Damage posterior to chiasm
| Cranial Nerve II - Optic Nerve | Page 3 of 11 |
Sensory Transduction
Light incident on the photoreceptor cells triggers a series of chemical reactions which alter plasma membrane permeability resulting in a hyperpolarization of the rod or cone.
This hyperpolarization of the photoreceptor cell can produce either an excitatory (depolarization) or inhibitory (hyperpolarization) response by the bipolar cell dependent on the nature of the synapse between the two cells.
The bipolar cells are the primary sensory neurons of the visual pathway. They synapse with and either excite or inhibit the action potential firing rate of the secondary sensory neurons - the ganglion cells.
The axons of the ganglion cells converge at the optic disc near the center of the retina to exit the eye as the optic nerve.
Figure 2-3. Sensory transduction.
