The fixation reflex is that concerned with attracting the eye on a peripheral object. For example, when a light shines in the periphery, the eyes shift gaze on it. It is controlled by the occipital lobe of the cerebral cortex, corroborated by three main tests:
# Removal of cortex causes shutdown of this reflex
# Drawing a figure on the cortex surface will cause eye movements in the direction traveled
# Detecting an image by recording the actual signals from the eyes
Older research declares that a
motor pathway from the
occipital cortex to the
brainstem
The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...
motor neurons was via the
superior colliculi. This is the case in lower animals, but in humans, the theory that eye-muscle nuclei (
oculomotor nucleus
The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. F ...
and
Edinger–Westphal nucleus) aside from the superior colliculi of the midbrain is now generally held.
When an object is focused directly at an object but the eyes drift off their target, the fixation reflex keeps the eyes focused on the original object, albeit moving itself.
See also
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Bibliography
*"eye, human."Encyclopædia Britannica. 2008.
Encyclopædia Britannica 2006 Ultimate Reference Suite DVD
An encyclopedia is a reference work or compendium providing summaries of knowledge, either general or special, in a particular field or discipline. Encyclopedias are divided into articles or entries that are arranged alphabetically by artic ...
{{Medicine-stub
Reflexes
Vision