1: Brainstem nuclei & function

Question 1

Cerebellum

Answer 1

This is the region comprised of cortex and deep nuclei dorsal to the brain stem. It is involved in coordination of voluntary movements and the learning of motor skills

Question 2

Cerebral aqueduct

Answer 2

CSF path through the midbrain that connects the third and fourth ventricle

Question 3

Deep cerebellar nuclei

Answer 3

Dentate, interposed, fastigeal (lateral to medial): The output nuclei from the cerebellum

Question 4

Dorsal columns

Answer 4

Fasiculus gracillus (lower extremity) and fasiculus cuneatus (upper extremity)- tracts that convey well-localized touch, pressure, vibration and joint position

Question 5

Pyramidal decussation

Answer 5

Crossing site of motor corticospinal tracts at caudal end of medullary pyramid. Marks the junction between spinal cord and brain stem

Question 6

Internal arcuate fibers

Answer 6

Nerve fibers arising from neurons of the nucleus gracilis and cuneatus (ipsalateral), passing ventrally and decussating to form the medial lemnsicus (contralateral). The are a distinctive feature of the caudal to mid medulla

Question 7

Inferior olivary nucleus

Answer 7

The large nucleus in the ventral lateral medulla that is the origin of cerebellar climbing fibers and that is critical for normal cerebellar function

Question 8

Medullary pyramid

Answer 8

fiber bundle in the ventral part of the medulla containing corticospinal tracts, which are involved in skilled movements of contralateral limbs.

Question 9

Cerebral peduncle (crus cerebri)

Answer 9

Ventral midbrain- cerebral cortical efferent projections to the brainstem (corticobulbar) and the spinal cord (corticospinal).

Question 10

Inferior cerebellar peduncle/restiform body

Answer 10

The connection from medulla to cerebellum that conveys nerve fibers from spinal cord and brain stem to the cerebellum

Question 11

Middle cerebellar peduncle/brachium pontis

Answer 11

This is the connection from the basal pons to cerebellum. It is a relay for connections from the cerebral cortex to cerebellum (cortico-pontine, ponto-cerebellar)

Question 12

Superior cerebellar peduncle/brachium conjunctivum

Answer 12

Connection from cerebellum to midbrain. Most of cerebellar outputs traverse this pathway.

Question 13

Medial lemniscus

Answer 13

Continuation of sensory axons from dorsal column nuclei and pass through the internal arcuate fibers. This tract relays dorsl colums sensations (well-localized touch vibration and joint sensation) rostrally through brain stem to the thalamus

Question 14

Medial longitudinal fasciculus (MLF)

Answer 14

Distinctive bundle of axons that includes several ascending and descending tracts. It is especially important in yoking together horizontal eye movements. Located near midline, just ventral to ventricle system

Question 15

Pontine nuclei /basal pons

Answer 15

Bulbous nucleus that forms the ventral aspect of pons. The termination of corticopontine fibers and origin for pontocerebellar projections through middle cerebellar peduncle

Question 16

Medial geniculate nucleus

Answer 16

Located in the caudal part of thalamus (of the diencepahlon) and relays auditory information from the inferior colliculus to the auditory cortex

Question 17

Lateral geniculate nucleus

Answer 17

Located in the caudal part of thalamus (part of diencepahlon). It is the termination of the optic tract and is a critical relay in the visual pathway.

Question 18

External/lateral cuneate nucleus

Answer 18

immeiately lateral to the nucleus cuneatus and relays proprioceptive information from the upper limbs to the cerebellum.

Question 19

Obex

Answer 19

Where the central canal opens up to the fourth ventricle.

Question 20

Tectum

Answer 20

The portion of the midbrain dorsal to the cerebral aqueduct (comprised of the colliculi)

Question 21

Superior colliculus

Answer 21

A nucleus that receives input from many sensations (especially vision) and is involved in producing reflex head and eye movement to novel stimuli

Question 22

Tegmentum

Answer 22

The term used for the “core” of the brain stem between the ventricle system dorsally and the motor structures in the ventral part of the brain stem (the pyramids and inferior olive in the medulla, the pontine nuclei in the pons and the crus cerebri and substantia nigra in the midbrain)

Question 23

Inferior colliculus

Answer 23

A relay for auditory pathway. It is located dorsal to cerebral aqueduct (in tectum)

Question 24

Raphe nuclei

Answer 24

Serotonin-containing neurons in midline of brain stem

Question 25

Red nucleus

Answer 25

Motor nucleus in midbrain, origin of the rubrospinal tract and projections to the inferior olivary nucleus

Question 26

Substantia nigra

Answer 26

Large nucleus of the midbrain located just dorsal to the crus cerebri. The pars compacts ia the major source of dopamine in basal ganglia. Degenerates in Parknson’s disease

Question 27

Periaqueductal gray

Answer 27

Nucleus surrounding the cerebral aqueduct that contains endogenous opiate neurons and activates descending pain suppression pathways

Question 28

Ventral tegmental area

Answer 28

A region of dopaminergic neurons in the midline of the ventral midbrain. The major dopamine source in the mesolimbic and mesocortical dopamine reward system (and addiction)