Term
| aside from vision, what functions does information received from the retinas intitate |
|
Definition
| 1. adjusting the size of the pupil; 2. regulation of circadian rhythm; 3. directing movements of the head |
|
|
Term
| where do axons of ganglion cells in the retina project |
|
Definition
| through the optic disk at the back of the retina |
|
|
Term
| what are the axons that project from the retina through the optic disk called |
|
Definition
|
|
Term
| where does the optic nerve go immediately after leaving optic disk |
|
Definition
|
|
Term
| what do optic nerve axons do at the optic chiasm |
|
Definition
| ~60% of axons cross to the other side. Remaining 40% continue ipsilaterally toward the thalamus |
|
|
Term
| what do we call these visual axons once they've passed the chiasm |
|
Definition
|
|
Term
| does an optic tract contain axons from one or both eyes |
|
Definition
|
|
Term
| why is the crossing of optic nerve fibers in the chiasm important/ what functional things result? |
|
Definition
| for binocular vision and stereopsis |
|
|
Term
|
Definition
|
|
Term
| where do fibers from the optic tracts project to (general areas of the brain?) |
|
Definition
| to 4 major structures within the midbrain and diencephalon |
|
|
Term
| what are the 4 major structures within the midbrain and diencephalon that fibers from the axon tracts project to |
|
Definition
| lateral geniculate nucleus of thalamus; hypothalamus; pretectum; superior colliculus |
|
|
Term
| where do neurons in the lateral geniculate nucleus of the thalamus send their axons to |
|
Definition
|
|
Term
| what do neurons in the lateral geniculate nucleus of the thalamus go through to get to the cortex |
|
Definition
|
|
Term
| in what part of the cortex do optic radiations from the lateral geniculate nucleus of the thalamus terminate |
|
Definition
| primary visual cortex/striate cortex |
|
|
Term
| where is the primary visual cortex |
|
Definition
|
|
Term
| what is the Brodmann's area of the primary visual cortex |
|
Definition
|
|
Term
| what is another term for the visual primary sensory cortex |
|
Definition
|
|
Term
| what are 2 terms for the pathway between the lateral geniculate nucleus of the thalamus and the primary visual cortex |
|
Definition
| geniculostriate pathway or primary visual pathway |
|
|
Term
| the information that they geniculostriate pathway conveys is essential for what? |
|
Definition
|
|
Term
| what does the primary visual cortex project to |
|
Definition
| temporal, parietal, and frontal lobes |
|
|
Term
| what are extrastriate visual projections |
|
Definition
|
|
Term
| what are the 2 extrastriate pathways |
|
Definition
| ventral pathway, dorsal pathway |
|
|
Term
| where does the ventral pathway project? |
|
Definition
|
|
Term
| what is the ventral pathway responsible for |
|
Definition
| object recognition (shape, color, texture) |
|
|
Term
| where does the dorsal pathway project |
|
Definition
|
|
Term
| what is the dorsal pathway responsible for |
|
Definition
| analysis of movement /spatial vision |
|
|
Term
| where in the frontal lobe does visual information project to |
|
Definition
|
|
Term
| what is the brodmann's area of the frontal eye fields |
|
Definition
|
|
Term
| where in the brain do we have object recognition |
|
Definition
|
|
Term
| what part of the hypothalamus do axons from the optic tract project to? |
|
Definition
|
|
Term
| what is the name of the pathway of axons from the retina to the suprachiasmatic nucleus the hypothalamus |
|
Definition
| retino-hypothalamic pathway |
|
|
Term
| what does the retino-hypothalamic pathway influence |
|
Definition
| circadian rhythm and visceral autonomic functions |
|
|
Term
| why is it that you can feel viscerally ill from seeing smoething? |
|
Definition
| retino-hypothalamic pathway carries the visual information and influences visceral autonomic functions |
|
|
Term
| what are axons that project to the pretectum from the retina responsible for |
|
Definition
|
|
Term
| what is the pupillar light reflex |
|
Definition
| light stimulates both pupils to constrict |
|
|
Term
| where do neurons from the pretectum project to |
|
Definition
| BOTH edinger-westphal nuclei in the midbrain |
|
|
Term
| where do preganglionic parasympathetic neurons in the edinger-westphal nucleus project |
|
Definition
|
|
Term
| what do preganglionic parasympathetic neurons go through from the edinger-westphal nucleus to get to the ciliary ganglion |
|
Definition
|
|
Term
| where do postganglionic parasympathetic neurons from the edinger-westphal nucleus go |
|
Definition
| to the sphincter pupillary muscle |
|
|
Term
| what do the postganglionic parasympathetics from the edinger-westphal nucleus do after they have synapsed on the preganglionic parasympathetics in the ciliary ganglion |
|
Definition
| cause constriction of the pupil |
|
|
Term
| what is the path of light coming into one eye |
|
Definition
| light comes in and projects to the retina. Goes to pretectum. Goes to edinger-westphal nuclei. Goes to ciliary ganglion via CN III, synapses, postganglionic causes constriction of the pupil |
|
|
Term
| how should pupils respond if one eye is stimulated by light |
|
Definition
| both pupils should constrict identically |
|
|
Term
| what is the direct response of light stimulation |
|
Definition
| constriction in the stimulated eye |
|
|
Term
| what is consensual response |
|
Definition
| constriction in the unstimulated eye |
|
|
Term
| what does a direct response to the left eye without a consensual response in the right eye indicative of |
|
Definition
| possible damage to the brainstem: Edinger-westphal nucleus or CN III |
|
|
Term
| why would you test pupillary response in someone who's unconscious |
|
Definition
| gives you an idea of what's happening in the midbrain |
|
|
Term
| where is the superior colliculus |
|
Definition
|
|
Term
| what do projections from the superior colliculus influence/coordinate |
|
Definition
| movements of the head and eyes - how we follow visual information around |
|
|
Term
| what are the 2 parts of the retina |
|
Definition
| nasal retina, temporal retina |
|
|
Term
| what part of the visual field is seen by the nasal retina |
|
Definition
|
|
Term
| what part of the visual field is seen by the temporal retina |
|
Definition
|
|
Term
| where do objects in periphery project to |
|
Definition
|
|
Term
| where do objects in front project to |
|
Definition
|
|
Term
| which axons from the retina will cross in the chiasm |
|
Definition
| ganglion cells in the nasal portion of the retina (the ones that see the periphery) |
|
|
Term
| which axons from the retina will not cross in the retina but will remain on the same side |
|
Definition
| ganglion cells in the temporal portion of the retina (the ones that see right in front) |
|
|
Term
| if you see an object directly in front of your left eye, what is its path? |
|
Definition
| falls on the nasal retina of the left eye and the temporal retina of the right eye. Axons from both project through the right optic tract |
|
|
Term
| on which retinal portions would an image to your right fall, and on which optic tract will it travel? |
|
Definition
| right nasal, left temporal. Left optic tract |
|
|
Term
| through which optic tract is information from the left visual field carried |
|
Definition
|
|
Term
| to which side of the primary visual cortex does the left visual field project |
|
Definition
|
|
Term
| through which optic tract is information from the right visual field carried |
|
Definition
|
|
Term
| to which side of the primary visual cortex does the right visual field project |
|
Definition
|
|
Term
|
Definition
| large visual field deficits |
|
|
Term
|
Definition
| smaller visual field deficits |
|
|
Term
|
Definition
| lose a quarter of a visual field |
|
|
Term
| what is the result of damage to the retina or optic nerve |
|
Definition
| loss of vision ipsilaterally |
|
|
Term
| what is the result of damage to the optic chiasm |
|
Definition
| affects fibers crossing from both nasal retinas but doesn't affect uncrossed fibers from the temporal retinas = lose periphery of visual field |
|
|
Term
| if you lose your optic nerve going to your right eye, what will you see |
|
Definition
| see everything from left eye |
|
|
Term
| if you lose your optic chiasm, what will you see |
|
Definition
|
|
Term
| what major gland sits right underneath the optic chiasm? |
|
Definition
|
|
Term
| what is the result of damage to the right optic tract? |
|
Definition
| loss of sight in the left visual field: loss of nasal visual field of right eye and loss of temporal visual field of left eye |
|
|
Term
| what is the result of damage to part of optic radiations |
|
Definition
|
|
Term
|
Definition
| portion of optic radiation that projects into the temporal lobe . Often damaged by strokes/tumors |
|
|
Term
| what is the exact path of meyer's loop |
|
Definition
| projections from the lateral geniculate to the visual cortex that swing laterally into the temporal lobe |
|
|
Term
| what part of the visual field is carried by the superior optic radiations |
|
Definition
|
|
Term
| what part of the visual field is carried by the inferior optic radiations |
|
Definition
|
|
Term
| what is the result of damage to the primary visual cortex |
|
Definition
| loss of a large vision of R or L visual field with sparing of foveal vision |
|
|
Term
| how many extraocular muscles are there |
|
Definition
|
|
Term
| what movements are useful models for studying motor contorl |
|
Definition
|
|
Term
| what have neuroscientists studied to learn about the cerebellum, basal ganglia, and vestibular systems |
|
Definition
|
|
Term
| what is essential for visual perceptin |
|
Definition
|
|
Term
| what is the region of highest visual acuity |
|
Definition
|
|
Term
|
Definition
| a small circular region on the retina that is densely packed with cone photoreceptors |
|
|
Term
| what is the role of our extraocular muscles |
|
Definition
| direct visual information to the fovea |
|
|
Term
|
Definition
| direction of visual information to the fovea |
|
|
Term
| what is a secondary responsibility of extraocular muscles |
|
Definition
| compensate for disturbances that cause the fovea to be displaced from a target already being attended to |
|
|
Term
|
Definition
| russian physiologist who studied eye movements |
|
|
Term
|
Definition
| the thin, straight lines/shifts of ballistic movements that our eyes constantly make |
|
|
Term
|
Definition
| align fovea with area of interest |
|
|
Term
| in Queen Neffertiti bust, what are the denser spots of eye movements |
|
Definition
| points of fixation where the subjects paused to perceive visual information |
|
|
Term
| how long do saccades last |
|
Definition
|
|
Term
| does visual perception occur during a sacade |
|
Definition
|
|
Term
| how is vision an active process |
|
Definition
| eye movements typically shift the view several times/second |
|
|
Term
| what do eye movements allow us to do |
|
Definition
| scan the visual field, pausing to focus attention on the portions of the scene that convey the most significant information |
|
|
Term
| what happens if youparalyze extra ocular muscles |
|
Definition
| image is projected to exactly the same parts of the retina. The stabilized retinal image disappears. You can't see |
|
|
Term
| what are the 3 antagonistic pairs of eye muscles that control eye movements |
|
Definition
| lateral/medial rectus; superior/inferior rectus; superior/inferior obliques |
|
|
Term
| what are the 3 axes of eye movements |
|
Definition
| horizontal, vertical, torsional |
|
|
Term
| what are the 2 options for horizontal eye movement |
|
Definition
|
|
Term
| what are the 2 options for vertical eye movement |
|
Definition
|
|
Term
| what are the 2 options for torsional eye movement |
|
Definition
|
|
Term
|
Definition
| bring the top of the eye toward the nose |
|
|
Term
|
Definition
| bring the top of the eye away from the nose |
|
|
Term
| what muscles control horizontal movements of the eye |
|
Definition
| medial and lateral rectus |
|
|
Term
| what muscles cause elevation of the eye |
|
Definition
| superior rectus and inferior oblique |
|
|
Term
| what muscles cause depression of the eye |
|
Definition
| inferior rectus and superior oblique |
|
|
Term
| what 3 cranial nerves innervate extraocular muscles |
|
Definition
| abducens, trochlear, oculomotor |
|
|
Term
| where in the brainstem is the abducens nucleus located |
|
Definition
|
|
Term
| what does the abducens innervate |
|
Definition
|
|
Term
| where does the trochlear nerve exit the brainstem |
|
Definition
|
|
Term
| what does the trochlear nerve do after exiting dorsal side of brainstem |
|
Definition
|
|
Term
| what muscle does the trochlear nerve innervate |
|
Definition
|
|
Term
| does the trochlear nerve innervate the ipsilateral or contralateral superior oblique |
|
Definition
|
|
Term
| where in the brainstem does the oculomotor nerve exit |
|
Definition
|
|
Term
| what does the oculomotor nerve innervate |
|
Definition
| all extraocular muscles except superior oblique and lateral rectus |
|
|
Term
| what do oculomotor parasympathetics do |
|
Definition
|
|
Term
| what provides innervation to the extraocular muscles along with the oculomotor nucleus |
|
Definition
| separate groups of lower motor neurons |
|
|
Term
| what are the 3 basic types of eye movements |
|
Definition
| saccades, smooth pursuit, vestibulo-ocular movements |
|
|
Term
|
Definition
| rapid, ballistic eye movements that abruptly change the point of fixation |
|
|
Term
| what is the range in amplitude of saccades |
|
Definition
| from small (reading) to large (scanning a room) |
|
|
Term
| are saccades voluntary or involuntary? |
|
Definition
| voluntary, but they occur reflexively/unconsciously. You can control them, but they happen so fast that we don't think about them. |
|
|
Term
| what are rapid eye movements |
|
Definition
| saccades that occur in our sleep |
|
|
Term
| when a target moves, how long does it take for eye movement to bgein |
|
Definition
|
|
Term
| what happens during the 200ms delay between movement of atarget and movement of the eye |
|
Definition
| the new position of the target with respect to the fovea is computed (how far the eye will have to move.) a motor command activates the extraocular muscles to move the eye the correct distance/direction |
|
|
Term
| can the saccade-generating system respond to changes in target position during the course of a saccade? |
|
Definition
|
|
Term
| what must happen if the target moves during a saccade |
|
Definition
| after the original saccade, another saccade must be generated to correct the error |
|
|
Term
| what do vestibulo-ocular movements/reflexes do |
|
Definition
| stabilize the eyes relative to head movements = compensate for head movements = prevent visual images from slipping on the surface of the retina as head position varies |
|
|
Term
| when do you use your Vestibulo-ocular reflex |
|
Definition
| when you look at a stationary object and move your head without removing your gaze |
|
|
Term
| what movements do eyes make to compensate for head movement using VOR |
|
Definition
| eyes move the same distance as the head but in the opposite direction |
|
|
Term
| what is the ultimate purpose of the VOR |
|
Definition
| keep the visual image on the same place of the retina |
|
|
Term
| what is it that directs the eyes to move in the direction opposite head movements in VOR |
|
Definition
| sensory information from the semicircular canals |
|
|
Term
| what 2 separate issues are involved in moving the eyes to fixate on a new target |
|
Definition
| controllowing the amplitude (how far) and controlling the direction (which way) |
|
|
Term
| what tells the eye how far to move (amplitude) in a saccade to fix on a target |
|
Definition
| amplitude is encoded by the duration of neuronal activity/action potentials in the LMNs of CN nuclei III, IV, VI |
|
|
Term
| what determines the direction of saccadic movements |
|
Definition
| which eye muscles are activated |
|
|
Term
| what controls which eye muscles are activated |
|
Definition
|
|
Term
| where are the 2 gaze centers |
|
Definition
|
|
Term
| what are the 2 gaze centers |
|
Definition
| paramedian pontine reticular formation, rostral interstitial nucleus |
|
|
Term
| what is the paramedian pontine reticular formation responsible for |
|
Definition
|
|
Term
| what is the rostral interstitial nucleus responsible for |
|
Definition
|
|
Term
| where is the paramedian pontine reticular formation |
|
Definition
| in the reticular formation of the pons, near the midline |
|
|
Term
| what does separate activation of the gaze centers result in |
|
Definition
| movement along a single axis: either vertical or horizontal |
|
|
Term
| what does activation of the gaze centers in concert result in |
|
Definition
| oblique movements, specified by relative contributions from each gaze center |
|
|
Term
| which 2 cranial nerves does the paramedian pontine reticular formation work with to make horiztonal eye movements |
|
Definition
|
|
Term
| does the paramedian pontine reticular formation innervate the ipsilateral or contralateral abducens nucleus |
|
Definition
|
|
Term
| what are the 2 types of neurons in the abducens nucleus |
|
Definition
| lower motor neurons, internuclear neurons |
|
|
Term
| what do lower motor neurons in the abducens nucleus do |
|
Definition
| innervate the lateral rectus muscle ipsilaterally |
|
|
Term
| what do internuclear neurons in the abducens nucleus do |
|
Definition
| send axons across the midline to the contralateral oculomotor nucleus |
|
|
Term
| through what tract does the internuclear neuron of the abducens send axons to the oculomotor nucleus |
|
Definition
| medial longitudinal fasciculus |
|
|
Term
| what is the medial longitudinal fasciculs |
|
Definition
| small axon that goes between cranial neurons to coordinate things |
|
|
Term
| How does the paramedian pontine reticular formation work in conjunction with the abducens and oculomotor nuclei to generate a horizontal saccade to the right |
|
Definition
| 1. Neurons in the right PPRF innervate cells in the right abducens nucleus. 2a. LMNs in the R abducens nucleus innervate the R lateral rectus. 2b. Internuclear neurons travel from the R abducens nucleus to the L oculomotor nucleus via the medial longitudinal fasciculus. 3. the L oculomotor nucleus contains LMNs that innervate the L medial rectus muscle |
|
|
Term
| what is the result of activation of the PPRF on the right side of the brainstem |
|
Definition
| horizontal movements of both eyes to the right |
|
|
Term
| how does activation of the R PPRF affect muscles that oppose eye movements toward the right |
|
Definition
| activation of the PPRF on the right results in a reduction of activity of LMNs whose muscles oppose eye movements to the right via inhibitory neurons |
|
|
Term
| How do visual stimuli activate the appropriate gaze center? In other words, how does visual sensory information concernint the location of a visual target initiate accurate saccadic eye movements? |
|
Definition
| projections to the gaze center from the frontal eye fields and superior colliculus |
|
|
Term
| what 2 important structures project to the gaze centers? |
|
Definition
| frontal eye fields, superior colliculus |
|
|
Term
| what do both the frontal eye fields and superior colliculus contain? |
|
Definition
| cells that respond to visual stimuli |
|
|
Term
| what do the cells that respond to visual stimuli in the frontal eye fields and superior colliculus do immediately prior to saccades? |
|
Definition
|
|
Term
| what does the frontal eye field project to |
|
Definition
| superior colliculus AND contralateral PPRF |
|
|
Term
| what does the superiro colliculus project to |
|
Definition
|
|
Term
| how can the frontal eye field control eye movements independent of the superior colliculus |
|
Definition
| frontal eye field projects to superior colliculus as well as to contralateral PPRF |
|
|
Term
| how are the frontal eye field and superior colliculus redundant |
|
Definition
| they both project to the PPRF control for saccades |
|
|
Term
| if you injure the frontal eye field on the R side of your brain, what will happen |
|
Definition
| you will have diffuclty making eye movements towards your L side |
|
|
Term
| what does injury to a frontal eye field result in |
|
Definition
| inability to make saccades to contralateral side |
|
|
Term
| what does injury to superior colliculus result in |
|
Definition
| delays in the accuracy and velocity of saccades |
|
|
Term
| if you lose either a frontal eye field or a superior colliculus, what will happen |
|
Definition
| over time, one will compensate for the loss of the other |
|
|
