Cuts of Pons/ Midbrain

Question 1

What are the cuts of the Pons

Answer 1

5- Cut thru caudal pons

6- Cut thru cranial pons

Question 2

What are the cuts of the Midbrain

Answer 2

7- Cut thru caudal midbrain

8- Cut thru Cranial midbrain

Question 3

notable contents of cut 5 (caudal pons) (5)

Answer 3

Bundles of corticospinal neurons and corticonuclear bundles (from primatry somatomotor cotex)

Pontine nucleus- Send info about intention of mvmt to CL cerebellum (thru middle cerebellar peduncle)

Facial colliculus- has motor nucleus of amducens and motor nuc of facial

Medial lemnicus

trapezoid body- Crossing chochlear fibes that go to lat lemnicus

Question 4

Notable contents of cut 6 (cranial pons) (4)

Answer 4

Motor nuc of trigeminal (to massicatory mm)

Sensory nuc of trigeminal

Sup cerebellar peduncle (midbrain to cerebellum)

Medial eminence- created by medial longitudinal fasciculus (from med vestibular nucleus to CN 3,4,6z)

Question 5

What identifys cut 7 from 8

Answer 5

Big decussating fibres of superior cerebellar peduccle

and red nucleus in cut 8

Question 6

Notable contents of caudal midbrain (cut 7)

Answer 6

decussasion of sup cerebellar peduncles

trochlear n

cerebral peduncles

Substantia niagra

periaquaductal grey matter

inf colliculus

cochlear fibres

mesencephalic nut of trigeminal

Question 7

What is the decussation of sup cerebellar peduncles (cut 7(

Answer 7

efferent conection of cerebellum thru superior cerebellar peduncles
when in midbrain they cross midline and go to red nucleus where it is either sent to thalmus or cross back to ant tegmental decussation

Question 8

what is the periaquaductal grey matter (cut 7)

Answer 8

Sorunds cerebral aquaduct and control some pain modulation thu endogenous opiods

Question 9

What oocupies the each middle path of the cerebral peduncles

Answer 9

corticospinal tract
Corticobulbar tract- path that goes to CN 5,7,12 and ambigous nuc)
Corticopontine

Question 10

What travels thru lat lemnicus + efffernt (cut 7)

Answer 10

Lat lemniscus is 50% fibres from CL chochlear n and 50% from IL chochlear n

can be sent to Medial geniculate body or
Inf colliculus (where it goes to medial geniculate body or CL side thry tecto spinal tract)

Question 11

What is the mesencephalic nuclus of trigeminal n for (cut 7)

Answer 11

For proprioception from head

Question 12

Notable structures of cranial Midbrain (cut 8)

Answer 12

red nucleus- sends info to CL rubrospinal tract and IL inf olivary complex From cerebellum

Nucleus of occulomotor n

Sup colliculus (visual reflex pathway)

medial lemniscus

Spinal lemniscus (spinothalamic axons to thalmus)

Trigeminal lemnicus

medial longitudinal fasiculus- for fixation of target w eyes)