Eyes Flashcards
What is located in the paramedian pontine reticular? aka the PPFR?
The center for lateral gaze
How does the PPFR communicate with the ocular motor nuclei?
via the MLF
Where is the center for vertical gaze located?
in a region just rostral to the oculomotor mucleus in the rostral midbrain
When you turn your eyes to glance at a visual object without having a moving target to follow this is known as a
saccade
What region initiates a saccade movement?
the frontal eye fields (part of the frontal cortex)
Neurons from the frontal eye fields then project to the ______ ______ in the coicobulbar tract
ipsilateral superior colliculus
In a saccade, where does the message relay to after the superior colliculus?
the contralateral PPFR
What exclusively controls the lens? The sympathetic or parasympathetic system?
parasympathetic system
What is the role of the pre-tectal area?
serves as the autonomic control center to coordinate the focusing of both lenses
where are the pre-ganglionic parasympathetic neurons located?
Edinger Westphal nuclei
What happens when the cillary muscle contracts?
decreases the tension of the lens allowing it to relax to a more spherical shape, allowing us to focus on nearby objects
The pre-tectal area also receives motor input from what?
the centers for convergence and divergence
The parasympathetic axons travel with what cranial nerve?
oculomotor nerve
What autonomic system(s) control the iris?
both the parasympathetic and sympathetic system
Where do the autonomic fibers for control of the iris synapse?
Parasympathetic: pretectal nucleus
Sympathetic: the midbrain reticular formation
What happens during parasympathetic activation of the iris?
contraction of the sphincter muscle and pupillary constriction
Describe the sympathetic pathway for autonomic control of the iris
innervation of the superior cervical ganglion which then innervates the dilator muscles of the iris
Where is the center for vertical and accommodation located
the midbrain
Where is the center for horizontal gaze located?
the pons
Where is the PPRF located?
just adjacent to the abducens nucleus in the pons
If the left PPRF is activated, what direction will the eyes move?
to the left
The MT cortex controls what kind of movement? where is the MT cortex found?
slow pursuit; temporal gyrus
the frontal eye fields initiate what kind of movement?
saccadic movement; found in the frontal lobe
The cuneus gyrus of the occipital lobe carry what information?
carries information from lower visual fields; in the parietal lobe
What does the lingual gyrus carry?
information from the upper visual fields along myers loop; temporal lobe
Damage to the R temporal lobe produces what visual symptoms?
“pie in the sky” on the left
What role does the hypothalamus play in receiving retinal ganglion cell axons?
circadian rhythm-“sleep, wake rhythm”
What do V3, V4, and V5 perceive?
color, form and movement
damage to this visual field would still allow someone to see but not be able to recognize the forms
V3
Damage to V4 produces what symptoms?
inability to recognize color
Damage to this visual field causes “motion agnosia”
V5
