Brainstem & Thalamus

Question 1

Cranial nerves in the thalamus include…

Answer 1

1. optic nerve (CN2)

Question 2

Cranial nerves in the midbrain include…

Answer 2

1. oculomotor (CN3)
2. trochlear (CN4)

Question 3

Cranial nerves in the pons include…

Answer 3

1. trigeminal (CN5)
2. abducens (CN6)
3. facial (CN7)
4. vestibulocochlear (CN8)

Question 4

Cranial nerves in the medulla include…

Answer 4

1. glossopharyngeal (CN9)
2. vagus (CN10)
3. accessory (CN11)
4. hypoglossal (CN12)

Question 5

Brainstem Functions

Answer 5

1. conduit for fibers of corticospinal & corticothalamic tracts
2. site of emergence for cranial nerves
3. integrate nuclei for motor, respiratory, and cardiovascular control

Question 6

Medulla Functions

Answer 6

1. respiration (sensing blood acidity)
2. reflexes (vomiting, coughing, sneezing, swallowing)
3. contains pyramidal decussation

Question 7

Olive

Answer 7

Located in the anterior medulla
Bulge containing nuclei for auditory processing

Question 8

Pyramid

Answer 8

Located in the anterior medulla
Descending corticospinal tracts

Question 9

Nuclei in the inferior medulla include…

Answer 9

1. vestibular
2. cochlear
3. trigeminal
4. olivary
5. hypoglossal
6. vagal
7. nucleus of solitary tract (NST)

Question 10

Blood Pressure Control

Answer 10

1. baroreceptors in the carotid body sense stretch
2. information is relayed along glossopharyngeal nerve to the NTS nuclei in the inferior medulla
3. vagal nuclei are activated
4. heart rate decreases, blood vessels dilate, sympathetic nervous system is inhibited

Question 11

Respiratory Control

Answer 11

Controlled in the pons and medulla
Dorsal respiratory group sets breathing rhythm and muscle contraction
Pontine respiratory group sets volitional control
PreBotC sets inspiration
RTN sets expiration
Sensory paths and NMS alter rhythm in arousal states

Question 12

Pons Functions

Answer 12

1. respiration, sleep, bladder control
2. sensory information (auditory & taste)
3. motor control of eyes and face
4. behavioral response to threats

Question 13

Medial eminence

Answer 13

Located on the posterior pons
Midline of the fourth ventricle

Question 14

Facial colliculus

Answer 14

Located on the posterior pons
Bulge of fibers from facial nerve wrapping around the abducens nucleus

Question 15

Stria medullaris

Answer 15

Located on the posterior pons
Fibers marking the boundary between the medulla and the pons

Question 16

Pontine reticular formation

Answer 16

Responsible for complex motor patterns
Integrating motor and cerebellar commands to fine tune motor patterns
Connects to medial reticulospinal tract

Question 17

Medullary reticular formation

Answer 17

Suppression of pain
Connects to lateral reticulospinal tract

Question 18

Lateral periaqueductal gray (LPAG)

Answer 18

Circuit to inhibit pathway that controls pain
Modulated by serotonin via raphe

Question 19

Midbrain Functions

Answer 19

1. release of dopamine (movement control and motivation)
2. sleep, wake, arousal
3. thermal regulation
4. nuclei for auditory and visual processing

Question 20

Superior colliculi

Answer 20

Located in midbrain
Motor control of the eyes

Question 21

Inferior colliculi

Answer 21

Located in midbrain
Second step of auditory processing

Question 22

Pineal gland

Answer 22

Production of melatonin during darkness
Contains pinealocytes and glial cells

Question 23

Serotonin

Answer 23

Reward and pleasure

Question 24

Dopamine

Answer 24

Reward prediction and seeking, motivation, and movement

Question 25

Norepinephrine

Answer 25

Arousal and attention

Question 26

Acetylcholine

Answer 26

Wakefulness, arousal, attention, memory, & motivation

Question 27

Reticular formation

Answer 27

Origin of cholinergic neurons that project to thalamus (regulating attention) Control of arousal, consciousness/awareness, attention Has reticulothalamic and monoamine projections that are key to consciousness

Question 28

Serotonergic neurons

Answer 28

Source: dorsal raphe, superior central nucleus Project to: amygdala, hippocampus, medial forebrain bundle, & spinal cord Signaling reward and pleasure

Question 29

Dopaminergic neurons

Answer 29

Source: ventral tegmental area, substantia nigra Project to: ventral striatum, dorsal striatum, motor cortex Signaling reward expectation, motivation, and movement

Question 30

Ventral tegmental area

Answer 30

Origin of dopaminergic neurons Projects to ventral striatum via medial forebrain bundle Signaling reward expectation & motivation

Question 31

Substantia nigra

Answer 31

Origin of dopaminergic neurons Projects to dorsal striatum & motor cortex Signaling movement

Question 32

Noradrenergic neurons

Answer 32

Source: locus coeruleus Project to: entire brain Signaling arousal & attention

Question 33

Cholinergic neurons

Answer 33

Source: basal nucleus & reticular formation Project to: cortex, thalamus Signaling wakefulness, arousal, attention

Question 34

Basal nucleus

Answer 34

Located in the forebrain Origin of cholinergic neurons Projects to the cortex & broad brain regions Regulating wakefulness & arousal

Question 35

Anterior group

Answer 35

Located in thalamus Input: hippocampus, limbic Output: cingulate cortex Involved in memory acquisition

Question 36

Ventral lateral

Answer 36

Located in thalamus Input: cerebellum Output: motor cortex Involved in motor functions

Question 37

Lateral geniculate

Answer 37

Located in thalamus Input: optic nerve Output: visual cortex 1st order visual relay

Question 38

Medial geniculate

Answer 38

Located in thalamus Input: auditory brainstem Output: auditory cortex 3rd order auditory relay

Question 39

Thalamic reticular

Answer 39

Located in thalamus Input: - Output: thalamic nuclei Inhibitory gate on thalamus; interconnected with GABAergic neurons

Question 40

Pulvinar

Answer 40

Located in thalamus Input: somatosensory tracts Output: all lobes of the brain Broad brain connections

Question 41

Internal capsule

Answer 41

Band of white matter surrounding the thalamus All connections to/from the cortex pass through it Connections to cortex are spatially ordered

Question 42

Basic circuits of the thalamus

Answer 42

1. relay 2. associational 3. intralaminar 4. reticular

Question 43

Relay circuit

Answer 43

Circuit of the thalamus Input: sensory Output: sensory cortex

Question 44

Associational circuit

Answer 44

Circuit of the thalamus Input: cortex Output: cortex Responsible for learning & regulation

Question 45

Intralaminar circuit

Answer 45

Circuit of the thalamus Input: thalamus, midbrain Output: cortex

Question 46

Reticular circuit

Answer 46

Circuit of the thalamus Input: thalamus Output: thalamus Intrathalamic inhibition

Question 47

Radiata

Answer 47

Dense white matter tracks that extend to the cortical lobes from the thalamus Travel through internal capsule & corona radiata