Neuro Fns Lect #23

Front 1

What are the dorsal boundaries of the mesencephalon?

Back 1

from the caudal border of the inferior colliculus to the posterior commissure

Front 2

What are the ventral borders of the mesencephalon?

Back 2

Superior pontine sulcus to the posterior border of the mammillary bodies

Front 3

This nerve decussates within the roof of the superior medullary velum and emerges on the dorsal aspect of the midbrain?

Back 3

Trochlear

Front 4

The two pairs of elevations on the dorsal aspect of the midbrain are collectively called the ?

Back 4

Corpora Quadrigemina

Front 5

The fiber bundle that connects the inferior colliculus with the thalamus is called the ?

Back 5

Brachium of the inferior colliculus

Front 6

This interconnecting fiber bundle on the dorsal aspect of the mesencephalon is overlain by the pineal?

Back 6

Posterior Commissure

Front 7

These are massive fiber bundles on the ventral aspect of the mesencephalon that contain the major efferent tracts from the cerebral cortex?

Back 7

Crura Cerebri

Front 8

What is the space between the crura cerebri called?

Back 8

interpeduncular fossa

Front 9

Thiis where blood vessels penetrate the midbrain at the floor of the interpeduncular fossa?

Back 9

Posterior perforated substance

Front 10

These nerves emerge from the floor of the interpeduncular fossa on the ventral aspect of the mesencephalon?

Back 10

Oculomotor nerve

Front 11

What are the three divisions that the midbrain can be divided into?

Back 11

tectum (roof), tegmentum, basis pedunculi

Front 12

The tectum consists of what caudally and rostrally ,respectively?

Back 12

inferior and superior colliculi

Front 13

This CSF-filled tunnel is located between the tectum and the tegmentum?

Back 13

cerebral aqueduct

Front 14

These cells surround the cerebral aqueduct and are densely-packed?

Back 14

periaqueductal gray

Front 15

What is located in the tegmentum of the mesencephalon?

Back 15

reticular formation, discrete nuclei and ascending/descending tracts

Front 16

What two things are found in the basis pedunculi?

Back 16

substanti nigra and crus cerebri (cortical output system)

Front 17

What are the three representative layers of the midbrain?

Back 17

inferior colliculus, superior colliculus, and pretectal region

Front 18

This is a major midbrain auditory relay nucleus within the midbrain?

Back 18

inferior colliculus

Front 19

The cochlear nuclei and superior olivary complex send input to the inferior colliculus via what tract?

Back 19

Lateral leminiscus

Front 20

Where do outputs from the inferior colliculus go?

Back 20

medial geniculate body of the thalamus via the brachium of the inferior colliculus

Front 21

What is the main function of the inferior colliculus?

Back 21

relay auditory impulses to higher levels; crucial for sound localization

Front 22

What are the inputs to the periaqueductal gray area of the brain?

Back 22

limbic areas of the forebrain

Front 23

What does stimulation of the periaqueductal gray area produce?

Back 23

profound analgesia

Front 24

This GSE nucleus is embedded in the MLF at the level of the inferior colliculus?

Back 24

trochlear nucleus

Front 25

what does the trochlear nucleus innervate?

Back 25

contralateral superior oblique muscle

Front 26

These crossing fibers from the cerebellum en route to thalamus largely fill the tegmentum at the level of the inferior colliculus?

Back 26

Decussation of Superior Cerebellar Peduncle

Front 27

This tract begins to fuse with the dorsal aspect of the medial leminiscus at the level of the inferior colliculus?

Back 27

spinothalamic tract

Front 28

These tracts from the cerebral cortex course in the medial and lateral 1/3 of the crura cerebri?

Back 28

corticopontine

Front 29

These tracts from the cerebral cortex course in the middle 1/3 of the crura cerebri?

Back 29

corticobulbar and corticospinal

Front 30

This nucleus forms a v shaped complex ventral to the PAG at the level of the superior colliculus?

Back 30

oculomotor nuclei

Front 31

The substantia nigra are at their maximal size at which representative level of the midbrain?

Back 31

superior colliculus

Front 32

This GVE nucleus is located dorsal to the somatic cell columns in the level of the superior colliculus?

Back 32

edinger-westphal nucleus

Front 33

What muscles are controlled by the edinger-westphal nucleus?

Back 33

ciliary muscle and constrictor pupillae

Front 34

How many cell layers does the superior colliculus have

Back 34

3 (superficial , intermediate, and deep

Front 35

This layer of the superior colliculus is involved in alerting visual areas to interesting visual stimuli and conscious localization of moving targets?

Back 35

Superficial layer of the superior colliculus

Front 36

What are the outputs of the superficial layer of the superior colliculus?

Back 36

thalamus via the brachium of the superior colliculus

Front 37

These layers of the superior colliculus receive inputs from visual, auditory and somatosensory stimuli and function in orienting the head toward these stimuli?

Back 37

Intermediate and deep

Front 38

The periaqueductal gray is best developed at which level of the midbrain?

Back 38

superior colliculus

Front 39

The oculomotor complex (nucleus) contains neurons of (GSE, GVE, both, neither)?

Back 39

Both

Front 40

What do the GSE nuclei of the oculomotor complex innervate?

Back 40

all extraocular muscles of the

Front 41

This is located ventral to the oculomotor nucleus in the reticular formation of the midbrain at the level of the superior colliculus?

Back 41

MLF

Front 42

This tract is located within the the reticular formation dorsal to the red nucleus?

Back 42

central tegmental tract

Front 43

The red nucleus is largely encapsulated by crossing fibers of what?

Back 43

superior cerebelar peduncle

Front 44

What is the function of the red nucleus?

Back 44

excite upper limb FLEXOR via rubrospinal tract

Front 45

This area of the substantia nigra is dorsally located and secretes dopamine?

Back 45

pars compacta

Front 46

This area of the substantia nigra is ventrally located and secretes GABA?

Back 46

pars reticulata

Front 47

This nucleus located in the pretectal midbrain, mediates the pupillary light reflex?

Back 47

pretectal olivary nucleus

Front 48

Where does the pretectal olivary nucleus send fibers to ?

Back 48

GVE (edinger-Westphal)

Front 49

This structure is dorsal to the cerebral aqueduct and PAG and demarcates the rostral end of the midbrain?

Back 49

Posterior commissure

Front 50

What does the posterior commissure contain at the pretectal level?

Back 50

crossing fibers of the pupillary light reflex of the contralateral eye

Front 51

What are the two nuclei found in the tegmentum in the pretectal region?

Back 51

accessory oculomotor and red nucleus

Front 52

When light is shone into one eye, both pupils constrict, what reflex is this?

Back 52

pupillary light reflex

Front 53

During the pupillary light reflex, the response in the opposite eye is (direct or indirect)?

Back 53

indirect pupillary light reflex

Front 54

What path does information take from the retina to the pretectal olivary nucleus during the pupillary light reflex?

Back 54

right retina > optic nerve > optic tract > brachium of the superior colliculus > pretectal olivary nucleus

Front 55

How do fibers from the pretectal olivary nucleus get to the contralateral edinger-westphal nucleus?

Back 55

via posterior commissure

Front 56

Which muscles are innervated during the pupillary light reflex?

Back 56

bilateral sphincter pupillae muscles

Front 57

Which nerves carries information from the edinger-westphal nucleus to the ciliary ganglion?

Back 57

oculomotor

Front 58

Which nerves carries information from the ciliary ganglion to the sphincter pupillae muscles?

Back 58

short ciliary nerves

Front 59

A lesion of the optic nerve will have what effect on the pupillary light reflex?

Back 59

The affected side will show no pupillary reflex for both eyes upon stimulation, unaffected stimulation will result in both pupillary reflexes

Front 60

A lesion in the oculomotor nerve will result in what effect on the pupillary reflex?

Back 60

The affected side will show no pupillary reflex when either eye is stimulated by light, unaffected side will show reflex upon stimulation of either eye

Front 61

A patient with complete ptosis of his r eyelid most likely has a lesion to what nerve?

Back 61

R oculomotor nerve (LMN ipsilateral effects)

Front 62

What are the only two extraocular muscles not innervated by the oculomotor nerve?

Back 62

lateral rectus and superior oblique

Front 63

In a lesion of the oculomotor, the affected eye is deviated in which direction due to unoppose action by the only two extraocular muscles not innervated by the oculomotor?

Back 63

laterally and downward

Front 64

Vascular disturbance in the posterior part of the circle of willis will result in what syndrome?

Back 64

Weber's syndrome (superior alternating hemiplegia)

Front 65

What are the symptoms of Weber's?

Back 65

ipsilateral oculomotor nerve palsy, contralateral hemiplegia, contralateral paralysis of lower facial muscles

Front 66

Lateral tegmental vascular infarct will result in what named syndrome?

Back 66

Benedikt's syndrome

Front 67

What 5 structures are involved in Benedikt's syndrome?

Back 67

red nucleus, SCP, medial leminiscus, spinothalamic tract, oculomotor nerve

Front 68

A patient complains of eyelid droop on his right side and tremors in his left limbs, as well as loss of pain and thermal sensation in his left arms and legs. What is the likely diagnosis?

Back 68

Benedikts syndrome (tegmental)

Front 69

Vascular disturbance in the tectum or pineal gland tumor can result in this?

Back 69

Collicular (parinaud's) syndrome

Front 70

What are some of the symptms of Parinaud's?

Back 70

paralysis of upward or downward gaze depending on the level of the midbrain lesion