Subcortical, intralobar, associative, and projection fibres were exposed until the optic radiation
(OR) on lateral and basal dissection and until the callosal-tapetal fibres on the mesial surface of the occipital lobe in each specimen.
Navigated three- dimensional intraoperative ultrasound-guided awake resection of low-grade glioma partially infiltrating optic radiation
Acta Neurochir 2012; 154: 1255-62.
Lesions involving optic radiation
: Optic radiation
is most commonly involved in lesions affecting internal capsule such as vascular, traumatic, brain abscess of otogenic origin.
He et al., "Directional diffusivity changes in the optic nerve and optic radiation
in optic neuritis," The British Journal of Radiology, vol.
The optic radiations
pass through the parietal lobe before passing through the temporal lobe and then reaching the visual cortex (Figure 3).
(18) Koniocellular cells within the LGN receive their input from bistratified retinal ganglion cells exiting the optic tract, and send their information via the optic radiation
to the primary visual cortex.
Upon leaving the LGN, the upper fibres of the optic radiations
take a relatively direct course backwards, spreading in a broad fan through tile parietal lobe to terminate in the occipital visual cortex.
In the normal healthy human brain, visual information is relayed from the lateral geniculate nucleus (LGN) to the primary visual cortex via the optic radiations
(for review, see Metzger et al.
- 5% supratentorially (typically in the optic radiations
Optic pathway gliomas can involve any portion of the visual pathway, including the hypothalamus, optic disc, nerve, chiasm, geniculate nucleus, and optic radiations
. Categorized as juvenile pilocytic astrocytomas, they account for 4-6% of all brain tumors in children, and the median age of diagnosis is 5-9 years [5, 53, 54].
Hemianopia due to the lesion in anterior optic tract is characteristically non congruous, while that due to pathology in posterior optic radiations
and occipital cortex are highly congruous1.
To quote Elisa Fazzi and her colleagues from Italy (2009): Cerebral visual impairment (CVI), a neurological disorder caused by damage to or malfunctioning of the retrogeniculate visual pathways (optic radiations
, occipital cortex, visual associative areas) in the absence of major ocular disease, (1) has been extensively studied in recent years.