NETTER - Neuroscience Flash Cards

Visual Pathways: Retinal Projections
to the Thalamus, Hypothalamus,
and Brain Stem
1. Axonal projections to visual cortex
2. Pulvinar
3. Pretectum
4. Superior colliculus
5. Nucleus of the accessory optic tract
6. Projections to preganglionic sympathetic neurons in T1 and T2
7. Lateral geniculate nucleus (body)
8. Suprachiasmatic nucleus (hypothalamus)
Comment: Ganglion cells of the retina send axons (equivalent to
lemniscal pathways of other sensory systems) through the optic
nerve, chiasm, and tract, to terminate in the lateral geniculate
nucleus (LGN) of the thalamus, superior colliculus, pretectum,
suprachiasmatic nucleus of the hypothalamus, and some brain
stem nuclei such as the nucleus of the accessory optic tract. The
pathway through the LGN mediates conscious interpretation of the
visual world. The pathway through the superior colliculus provides
additional localizing information regarding vision and mediates reflex
visual effects on head and neck movement. The pathway through the
pretectum mediates the pupillary light reflex. The pathway through
the suprachiasmatic nucleus integrates total light flux and regulates
circadian rhythms and diurnal cycles. The pathway through the
nucleus of the inferior accessory optic tract may help to mediate
brain stem responses for visual tracking and helps to mediate
sympathetic preganglionic neurons in the T1 and T2 spinal cord.
Systemic Neuroscience See book 14.28