Monday 1 - Severson - neuro lab 8

Question 1

Where are betz cells in the brain

Answer 1

Agranular layer of the MOTOR cortex - later 5 of that

Question 2

horizontal control center of gaze

Answer 2

paramedian pontine reticular formation, right lateral to abducens nucleus

Question 3

vertical control center of gaze

Answer 3

rostral midbrain (rostral MLF)

Question 4

Corticospinal tract from brain to muscle

Answer 4

pyramidal cells in cortex, more medial than the corticobulbar in the homunculus

posterior limb of internal capsule

cerebral peduncles in the midbrain, more lateral than the corticobulbar

basilar pons (it’s right in the middle of the pons)

pyramids of medulla

CROSS OVER at the pyramidal deccusation

in the spinal cord, they are in the lateral corticospinal tract

Question 5

somatotopic organization of the posterior limb of the internal capsule

what fibers run here?

Answer 5

nearest genu (anterior)

it goes: cervical, thoracic, lumbar, sacral

corticospinal

Question 6

what does the pyramidal tract consist of

Answer 6

corticospinal and corticobulbar tracts

Question 7

somatotopic organization of the corticospinal tract in the spine

Answer 7

sacral - lateral
lumbar - more medial
thoracic fibers - even more medial
cervical fibers - most medial, if they haven’t already gone into the lateral horn.

Question 8

corticobulbar tract from brain to muscle

Answer 8

pyramidal cells in cortex, more lateral in the humunculus than the corticospinal

genu of the internal capsule

cerebral peduncles in midbrain, more medial than the corticospinal, some branch off into the occulomotor nucleus here

“big, dark eyes” in the pons, some branch off bilaterally to form trigeminal nucleii here

Ponto-medulary region, some branch off bilaterally into the facial nuclei

Medulla where it branches off in to the hypoglossal and nucleus ambiguus

Question 9

Cortico-olivary tract from brain to where it ends

Answer 9

motor cortex

ipsilateral to inferior olivary nucleus

“its very simple”

Question 10

Rubro-olivary tract

Answer 10

red nucleus

inferior olivary nucleus

“also very simple”

Question 11

Cortico pontine

Answer 11

z

Question 12

inferior olivary nucleus gives rise to what

Answer 12

climbing fibers

Question 13

Cortico-cerebellar pathway

Answer 13

cortex

goes to IPSILATERAL pontine nucleus as corticopontine cract

synapse in pons

crosses contralaterally

is now the pontocerebellar tract

goes to middle cerebellar peduncle and into the cerebellum as mossy fibers in the granular cell layer (innervates the deep cerebellar nuclei)

Question 14

What connects the occulomotor, trochlear, and abducens nuclei?

Answer 14

medial longitudinal fasciculus

Question 15

vestibulocollic reflex

Answer 15

when you go down you extent your head

Question 16

vestibulospinal reflex

Answer 16

coordinates head and neck with body, keeping head in upright position

Question 17

reticular formation

Answer 17

in brain stem, pons and medulary both

packing material between all of the nuclei like the facial nucleus and nucleus ambiguus.

involved in arousal and consciousness

black box for respiratory function, cardiovascular function

Question 18

olivocerebellar fibers pathway

Answer 18

olive in the medulla

cross over

go to inferior cerebellar peduncle

terminate in molecular layer of cerebellum as climbing fibers

Question 19

what do the climbing fibers in the cerebellum innervate

Answer 19

deep cerebellar nuclei

and

purkinje cells

(this seems counter-intuitive because the purkinje cells inhibit the deep cerebellar nuclei but the climbing fibers stimulate both)

Question 20

what is the general purpose of the inferior olive (think really general)

Answer 20

it modifies information and sends it to the cerebellum via the inferior cerebellar peduncle

Question 21

what innervates the deep cerebellar nuclei?

Answer 21

Trick question:

everything going into the cerebellum innervates the deep cerebellar nuclei

Question 22

what forms the paralell fibers in the cerebellum?

Answer 22

the granule cells

Question 23

everything in the molecular layer of the cerebellum is

Answer 23

excitatory

purkinje cells are the only things that are inhibitory

Question 24

when there is a lesion in the cerebellum, it presents on the _______ side

Answer 24

ipsilateral

Question 25

What tract(s) give info to the cerebellum (unconscious proprioception) regarding what is going on in the limbs

which peduncle do they go through

and what do they synapse on

Answer 25

dorsal spinocerebellar (lower limb) and cuneocerebellar (upper extremity)

inferior cerebellar peduncle

like ALL mossy fibers, they synapse on deep cerebellar nuclei and granule cells

Question 26

what two types of fibers go into the cerebellum

where do they come from

what do they synapse onto

Answer 26

Climbing fibers -
from inferior olivary nucleus
synapse onto the deep cerebellar nuclei and the purkinje cells

mossy fibers -
everything else
synapse on granule cells and deep cerebellar nuclei

Question 27

The fastigial nucleus is associated with what system

Answer 27

vestigial nuclei

Question 28

What comes from the cerebellum up to the cortex through the superior cerebellar peduncle?

Answer 28

Dentato-rubro-thalamic fibers

efferent fibers from the dentate, emboliform, and globose nuclei (but not fastigial)

Question 29

Dentato-rubro-thalamic tract

goes from where to where?

ipsilateral to where?
contralateral to where?

crosses over where?

Answer 29

goes from cerebellum to cerebrum via the superior cerebellar peduncle

ipsilateral to body
contralateral to cerebrum (red nucleus and thalmus)

crosses over at the decussation of the superior cerebellar peduncle,

Question 30

excitatory basal ganglia pathway (direct pathway)

Answer 30

motor cortex

striatum (caudate and putamen)

globus pallidus interna

thalmus

back to the cortex

Question 31

indirect basal ganglia pathway vs direct

Answer 31

indirect - inhibition of motor function via STN activating GPi

direct - excitation of motor function via striatum inhibiting GPi

Question 32

Lesion in the sub thalamic nucleus produces what

Answer 32

hemiballismus - wild swinging of the extremity on the contralateral side

Question 33

where is dopamine synthesized in the basal ganglia

Answer 33

the nerve terminals of the substantia nigra compacta, which terminate on the striatum