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Schematic diagram of pupillary light reflex neural pathway. Left direct light reflex involves neural segments 1, 5, and 7. Segment 1 is the afferent limb, which includes the retina and optic nerve. Segments 5 and 7 form the efferent limb. Left consensual light reflex involves neural segments 2, 4, and 7. Segment 2 is the afferent limb.
Lesions in that pathway cause a variety of visual field defects. In the visual system of human eye , the visual information processed by retinal photoreceptor cells travel in the following way: Retina → Optic nerve → Optic chiasma (here the nasal visual field of both eyes cross over to the opposite side)→ Optic tract → Lateral ...
In neuroanatomy, the pretectal area, or pretectum, is a midbrain structure composed of seven nuclei and comprises part of the subcortical visual system.Through reciprocal bilateral projections from the retina, it is involved primarily in mediating behavioral responses to acute changes in ambient light such as the pupillary light reflex, the optokinetic reflex, and temporary changes to the ...
It is performed by shining a light in the person's eyes and observing where the light reflects off the corneas. In a person with normal ocular alignment the light reflex lies slightly nasal from the center of the cornea (approximately 11 prism diopters—or 0.5mm from the pupillary axis), as a result of the cornea acting as a temporally-turned ...
There is a direct correspondence from an angular position in the visual field of the eye, all the way through the optic tract to a nerve position in V1 up to V4, i.e. the primary visual areas. After that, the visual pathway is roughly separated into a ventral and dorsal pathway.
Dilation and constriction of the pupil. Pupillary response is a physiological response that varies the size of the pupil, via the optic and oculomotor cranial nerve.. A constriction response (), [1] is the narrowing of the pupil, which may be caused by scleral buckles or drugs such as opiates/opioids or anti-hypertension medications.
Pupillary light reflex — a reduction of pupil size in response to light. Rectoanal inhibitory reflex - a transient relaxation of the internal anal sphincter in response to rectal distention. Rooting reflex — turning of an infant's head toward anything that strokes the cheek or mouth. Righting reflex - a proprioceptive reflex
Adie's pupil is caused by damage to peripheral pathways to the pupil (parasympathetic neurons in the ciliary ganglion that cause pupillary constriction to bright light and with near vision). The pathophysiologic mechanism which produces an Argyll Robertson pupil is unclear, but is believed to be the result of bilateral damage to the pretectal ...