3D Models Related Images

Lateral Geniculate Body and the Visual Pathway

Surgical Correlation


The CNS visual pathway. In this ventral dissection of a whole brain, the entire CNS visual pathway from optic chiasm to near the calcarine cortex is demonstrated.  Within the optic chiasm, optic nerve fibers undergo a partial decussation.  The net result is that information from the entire left visual hemifield enters the right optic tract and projects to the right half of the brain, and vice versa.  The optic tract extends caudally from the optic chiasm and runs initially along the lateral surface of the hypothalamus, then wraps around the lateral edge of the midbrain cerebral peduncle before terminating in the lateral geniculate nucleus (LGN) of the thalamus.  The latter nucleus lies on the anterolateral inferior surface of the pulvinar.  Axons of LGN neurons form the optic radiation, which conveys visual information to the primary visual cortex in the occipital lobe.  The optic radiation is visuotopically organized.  Fibers carrying information from the inferior half of the visual field enter the superior part of the optic radiation and travel through the parietal lobe in close proximity to the tapetum of the corpus callosum.  In contrast, fibers carrying information from the superior half of the visual field course anteriorly into the temporal lobe as Meyer's loop.  The latter fibers, as seen in this dissection, travel first in the roof of the temporal horn, and then loop posteriorly along the lateral wall of the temporal horn and atrium of the lateral ventricle, to form the inferior part of the massive fan-shaped optic radiation.  (Image courtesy of PA Rubino)