NeuroAnatomy - Lecture Seven Objectives Thalamus & Basal Ganglia

Question 1

Where is the Thalamus located?

Answer 1

the lateral regions of the diencephalon // “sit on top of the brainstem”

Question 2

Where is the Thalamus in relation to the Internal Capsule?

Answer 2

Thalamus is located medial to the IC

Question 3

What is the blood supply of the thalamus?

Answer 3

deep branches of the posterior cerebral atery (PCA) and posterior communicating arteries

Question 4

What is the function of the thalamus?

Answer 4

relays and regulates all sensory information going to cortex EXCEPT olfactory

Question 5

The thalamus acts as the blank…

Answer 5

gateway to consciousness

Question 6

What is the pathway for the visual function of the thalamus?

Answer 6

eye → thalamus → primary (1°) visual cortex (area 17) → secondary/associative visual cortices

Question 7

What is the pathway for the auditory function of the thalamus?

Answer 7

ear → thalamus → primary (1°) auditory cortex (area 41) → secondary/associative auditory cortices

Question 8

What is the pathway for the somatosensory function of the thalamus?

Answer 8

body → thalamus → primary (1°) somatosensory cortex (area 3,1,2) → secondary/associative somatosensory cortices

Question 9

What are the 5 Thalamic Nuclei?

Answer 9

Medial Geniculate (MGN), Lateral Geniculate (LGN), Ventral Posterior Medial (VPM), Ventral Posterior Lateral (VPL), and Ventral Lateral (VL)

Question 10

Where does the MGN get it’s information from?

Answer 10

the brainstem

Question 11

Where does the MGN send it’s information to?

Answer 11

primary auditory cortex (Brodmann’s 41)

Question 12

Where is the MGN located on the Thalamus?

Answer 12

posterior small bump, medially

Question 13

What type of information does the MGN carry?

Answer 13

Auditory

Question 14

Where does the LGN get it’s information from?

Answer 14

the eye

Question 15

Where does the LGN send it’s information to?

Answer 15

primary visual cortex (brodmann’s 17)

Question 16

Where is the LGN located on the Thalamus?

Answer 16

posterior small bump, laterally

Question 17

What type of information does the LGN carry?

Answer 17

visual

Question 18

Where does the VPM get it’s information from?

Answer 18

cranial nerves

Question 19

Where does the VPM send it’s information to?

Answer 19

primary somatosensory cortex (Brodmann’s 3,1,2)

Question 20

Where is the VPM located on the Thalamus?

Answer 20

posterior-medial

Question 21

What type of information does the VPM carry?

Answer 21

somatosensory information of head/face

Question 22

Where does the VPL get it’s information from?

Answer 22

spinal cord

Question 23

Where does the VPL send it’s information to?

Answer 23

primary somatosensory cortex (Brodmann’s 3,1,2)

Question 24

Where is the VPL located on the Thalamus?

Answer 24

posterior-lateral thalamus

Question 25

What type of information does the VPL carry?

Answer 25

somatosensory information of body

Question 26

Where does the VL get it's information from?

Answer 26

basal ganglia and cerebellum

Question 27

Where does the VL send it's information to?

Answer 27

primary and premotor cortex (brodmann's 4 and 6)

Question 28

Where is the VL located on the Thalamus?

Answer 28

mid thalamus, laterally

Question 29

What type of information does the VL carry?

Answer 29

motor information

Question 30

What is the clinical name of Thalamic Pain Syndrome?

Answer 30

Dejerine-Roussy Syndrome

Question 31

How is Dejerine-Roussy Syndrome caused?

Answer 31

Lacunar/Small vessel stroke that occurs in posterior thalamus and damages somatosensory pathways to cortex

Question 32

What are the symptoms of Dejerine-Roussy Syndrome?

Answer 32

contralateral loss of sensation, neuropathic pain (burning, shooting, stabbing, throbbing, etc)

Question 33

Where is the basal ganglia located?

Answer 33

in the diencephalon and midbrain

Question 34

What is the basal ganglia pathway?

Answer 34

anterior association area → premotor cortices/motor cortex → basal ganglia → thalamus → premotor/primary motor cortices

Question 35

What happens if there is a lesion in the basal ganglia/cerebellum?

Answer 35

there will be impaired motor function

Question 36

What does impaired basal ganglia movement look like?

Answer 36

hypokinesia or hyperkinesia

Question 37

What does impaired cerebellum movement look like?

Answer 37

motor tone, balance/posture, and coordination are all impaired

Question 38

What are the structures within the basal ganglia?

Answer 38

caudate nucleus, nucleus accumbems, putamen, globus pallidus external/internal, subthalamic nuclei, substantia nigra

Question 39

What is the "striatum" in the basal ganglia?

Answer 39

caudate and putamen

Question 40

What is the "lenticular nucleus" in the basal ganglia?

Answer 40

globus pallidus and putamen

Question 41

What is the blood supply of the basal ganglia?

Answer 41

Lenticulostriate arteries // smaller portion of basal ganglia supplied by small penetrating branches of ACA

Question 42

What is the function of the basal ganglia?

Answer 42

initiating and executing movement

Question 43

What are the 3 pathways of the basal ganglia?

Answer 43

motor loop, association (cognitive) loop, and limbic loop

Question 44

What is the function of the motor loop of the basal ganglia?

Answer 44

modifies the motor plan to initiate and execute movement

Question 45

What is the association (cognitive) loop of the basal ganglia?

Answer 45

learning/choosing the best ways to initiate and execute movement

Question 46

What is the limbic loop of the basal ganglia?

Answer 46

supplies emotional input to the motor plan and influences how movement is initiated and executed

Question 47

What is the motor loop pathway?

Answer 47

Premotor/motor cortex sends motor plan → putamen → globus pallidus internus → thalamus

Question 48

What does Dopamine/Ach do in the motor loop DIRECT pathway?

Answer 48

Dopamine stimulates the direct pathway/promotes movement and Ach inhibits the direct pathway/supresses movement

Question 49

What does Dopamine/Ach do in the motor loop INDIRECT pathway?

Answer 49

Dopamine inhibits the indirect pathway and promotes movement / Ach stimulates the indirect pathway and supresses movement

Question 50

What produces Dopamine in the basal ganglia?

Answer 50

Substantia nigra

Question 51

What produces Ach in the basal ganglia?

Answer 51

Putamen

Question 52

What is a hypokinetic disorder?

Answer 52

loss of dopamine / excess Ach and supresses movement. Pt has difficulty initiating / executing tasks

Question 53

What is a hyperkinetic disorder?

Answer 53

loss of Ach / excess dopamine and promotes too much movement. Pt experiences constant initiation and execution of abnormal movements

Question 54

what is the order of movement disorders listed from slowest to fastest?

Answer 54

bradykinesia, rigidity, dystonia, athetosis, chorea, ballismus, tic, myoclonus, and clonus

Question 55

What is bradykinesia?

Answer 55

slowed movement

Question 56

what is rigidity?

Answer 56

increased resistance to PROM // bi-directional

Question 57

what is lead-pipe rigidity?

Answer 57

resistance persists throughout entire ROM

Question 58

what is cogwheel rigidity?

Answer 58

periodic resistance at different points throughout ROM

Question 59

what is dystonia?

Answer 59

involuntary, sustained, or intermittent muscle contractions that cause twisting/repetitive movements, abnormal postures, or both

Question 60

what is athetosis?

Answer 60

slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture]

Question 61

which is slower: dystonia or athetosis?

Answer 61

dystonia

Question 62

what is chorea?

Answer 62

ongoing random-appearing sequence of one or more discrete involuntary movements // "dance-like involuntary movements"

Question 63

what is hemi-ballismus?

Answer 63

flailing, flinging, or rotary movements of proximal limbs

Question 64

where would a lesion be that causes hemi-ballismus?

Answer 64

a lesion in the subthalamic nuclei // indirect pathway

Question 65

what are tics?

Answer 65

repeated, individually recognizable, intermittent movements

Question 66

what are the two tics?

Answer 66

motor tics and vocal tics

Question 67

what are tremors?

Answer 67

Rhythmic back-and-forth or oscillating involuntary movement about a joint axis

Question 68

what is a resting tremor?

Answer 68

oscillating movement occurs at rest in a postural position, but once movement starts the tremor stops

Question 69

what is an intention tremor?

Answer 69

oscillating movement occurs as arm approches "intended target" and tremor increases as target gets closer. Stops when arm is resting in postural position

Question 70

what is myoclonus?

Answer 70

Sequence of repeated, often non-rhythmic, brief shock-like jerks due to sudden involuntary contraction or relaxation of one or more muscles

Question 71

what is clonus?

Answer 71

Muscular spasm involving repeated, often rhythmic, rapid contraction/relaxation