Is the optic nerve ipsilateral?

Is the optic nerve ipsilateral?

The optic nerves of both eyes meet at the optic chiasm and form the optic tracts. At the optic chiasm, the nasal retinal fibers from each optic nerve decussate (crossover) into the contralateral optic tract, while the temporal retinal fibers remain in the ipsilateral optic tract.

Is the visual system ipsilateral?

In lower-tier visual areas, this ipsilateral input occurs primarily near the retinotopic representation of the vertical meridian. It is likely that a similar representation of the ipsilateral visual field exists in human visual cortex (17–19).

Do all axons cross at the optic chiasm?

The number of axons that do not cross the midline and project ipsilaterally depends on the degree of binocular vision of the animal (3% in mice and 45% in humans do not cross).

Is the primary visual cortex contralateral?

The primary visual cortex (V1) has a representation of the contralateral visual hemifield. The foveal region is mapped in its most posterior part, whereas the more peripheral regions are mapped in progressively more anterior parts.

Do the optic nerves cross over?

At a structure in the brain called the optic chiasm, each optic nerve splits, and half of its fibers cross over to the other side. Because of this anatomic arrangement, damage along the optic nerve pathway causes specific patterns of vision loss.

Which axons cross the midline in the optic chiasm?

Contralateral axons cross the chiasm midline as they progress from the optic nerve to the optic tract. In contrast, ipsilateral axons deviate from the chiasm and continue in the ipsilateral optic tract, avoiding the chiasm midline.

What visual field crosses at the chiasm?

In the optic chiasm, the fibers of the nasal retina (i.e., the temporal visual field) of each eye cross, whereas the fibers of the temporal retina (i.e., the nasal visual field) of each eye proceed uncrossed.

What crosses at optic chiasm?

At optic chiasm, the fibers from the nasal half cross while the fibers from the temporal half remain uncrossed. From the optic chiasm, fibers pass to the optic tract. The left optic tract contains uncrossed temporal fibers from the left eyeball and crossed nasal fibers from the right eyeball.

What is contralateral visual field?

Definition. The region of visual space that extends from the vertical meridian (which passes through the center of gaze) peripherally toward the side of the body opposite to the neuron or brain region studied. In general, each side of the brain processes information from the contralateral visual field.

Where do axons project in the visual pathway?

From the LGN, axons project via the optic radiation to the occipital cortex of the cerebrum. Throughout the visual pathway, there is a retinotopic organization whereby axons from specific regions of the retina project to a specific area of the LGN and also the occipital cortex.

Which is part of the optic nerve forms the optic tract?

The axons of the retinal ganglion cells converge to form the optic nerve , which after a partial decussation at the optic chiasm forms the optic tract. The optic tract is an important part of the visual pathway.

What happens to the right side of the optic tract?

Optic tract lesions. A lesion on the right side of the optic tract may lead to left homonymous hemianopia. Partial injury to the optic tract may affect only one quadrant of the visual field. The resulting condition is called quadrantic anopia.

Where are the nerve fibers of the visual pathway located?

At the end of each optic tract, the retinal nerve fibers connect with other visual pathway nerves in a structure called the lateral geniculate nucleus (LGN) located in the midbrain.