internal capsule and basal ganglia

Question 1

basal ganglia function

Answer 1

• fine-tune voluntary movements
• goal-directed voluntary movements

Question 2

basal ganglia receive info from ?, processes it, and send it to ?

Answer 2

cerebral cortex; adjusted info back to cerebral cortex

Question 3

cortex sends adjusted info to ? via ?

Answer 3

skeletal muscles; pyramidal system

Question 4

basal ganglia definition

Answer 4

• a group of subcortical nuclei
• responsible primarily for motor control, motor learning, executive functions and behaviors, and emotions
• extrapyramidal system (involuntary)

Question 5

5 pairs of nuclei in basal ganglia

Answer 5

• caudate nucleus
• putamen
• globus pallidus
• subthalamic nucleus
• substantia nigra

Question 6

lentiform nucleus

Answer 6

• putamen
• globus pallidus

Question 7

striatum

Answer 7

• caudate nucleus
• putamen

Question 8

internal capsule

Answer 8

a big group of white matter axonic tracts

Question 9

caudate nucleus

Answer 9

• elongated c-shaped nucleus lateral to the lateral ventricles
• head, body, tail
• continuous with putamen
• connects with amygdala

Question 10

caudate nucleus tail forms ?

Answer 10

roof of the inferior horn of the lateral ventricles

Question 11

caudate nucleus function

Answer 11

• sends information to the thalamus about body and limb position
• goal-oriented behavior, learning, emotion

Question 12

underactive caudate nucleus associated with ?

Answer 12

depression and schizophrenia

Question 13

putamen

Answer 13

• encircled by the caudate nucleus
• most lateral structure of the basal ganglia
• regulates motor functions

Question 14

globus pallidus

Answer 14

• medial to the putamen
• external and internal segments
• control conscious and proprioceptive movements

Question 15

substantia nigra

Answer 15

• in the midbrain but part of the basal ganglia
• contains neuromelanin
• two subcomponents: pars compacta and pars reticulata

Question 16

pars compacta

Answer 16

• dorsal subcomponent of substania nigra
• melanin-filled neurons
• unknown function but dopamine neuron death causes Parkinson disease

Question 17

pars reticulata

Answer 17

• ventral subcomponent of substantia nigra
• controls eye movement

Question 18

large number of motor and sensory fibers travel to and from the cortex via ?

Answer 18

internal capsule

Question 19

3 subdivisions of the internal capsule

Answer 19

• anterior limb
• genu
• posterior limb

Question 20

anterior limb of internal capsule

Answer 20

• frontopontine fibers
• thalamocortical fibers

Question 21

genu of internal capsule

Answer 21

corticobulbar fibers

Question 22

posterior limb of internal capsule

Answer 22

• corticospinal fibers
• ascending sensory fibers

Question 23

frontopontine fibers

Answer 23

frontal cortex to pons

Question 24

thalamocortical fibers

Answer 24

thalamus to frontal lobe

Question 25

corticobulbar fibers

Answer 25

cortex to brainstem

Question 26

corticospinal fibers

Answer 26

cortex to spinal cord

Question 27

extrapyramidal system function

Answer 27

involuntary and automatic control of movements, posture, and muscle tone

Question 28

extrapyramidal system structures involved

Answer 28

- basal ganglia - red nucleus - substantia nigra - reticular formation - cerebellum

Question 29

basal ganglia input

Answer 29

all of cortex (except primary visual and auditory cortices)

Question 30

corticostriatal pathways

Answer 30

pathways that give input to basal ganglia

Question 31

axons from striatum synapse with ?

Answer 31

globus pallidus or pars reticulata

Question 32

basal ganglia output structures

Answer 32

- globus pallidus - pars reticulata

Question 33

basal ganglia output (globus pallidus)

Answer 33

- axons synapse with thalamus - thalamus relays info back to motor cortex (feedback loop)

Question 34

basal ganglia output (pars reticulata)

Answer 34

- axons synapse with upper motor neurons in the superior colliculus - regulate eye movement

Question 35

basal ganglia dysfunction

Answer 35

damage or degeneration to basal ganglia results in involuntary movements or motion impairment

Question 36

types of basal ganglia dysfunction

Answer 36

- involuntary movement disorders - impairments to motion disorders - parkinson's disease - huntington's disease

Question 37

involuntary movement disorders

Answer 37

- tremor (often resting tremor) - athetosis - chorea - ballism - dystonia

Question 38

athetosis

Answer 38

slow involuntary writing or twisting movements

Question 39

chorea

Answer 39

fast or jerky involuntary writing movements of the extremeties

Question 40

ballism

Answer 40

- similar to chorea - associated with more proximal extremities like shoulders and hips

Question 41

dystonia

Answer 41

involuntary contractions of muscles

Question 42

impairments to motion disorders

Answer 42

- akinesia - bradykinesia - shuffling gait - speech difficulties - loss of postural reflexes

Question 43

akinesia

Answer 43

lack of movement

Question 44

bradykinesia

Answer 44

slow movement

Question 45

parkinson's disease is a type of ?

Answer 45

parkinsonism

Question 46

parkinsonism

Answer 46

umbrella term for bradykinesia, tremor, rigidity

Question 47

parkinson's causes

Answer 47

- death of dopamine secretion in the substantial nigra - exact cause in unknown - associated with exposure to toxins, historical head trauma, infection, genetics

Question 48

parkinson's treatment

Answer 48

- L-DOPA - deep brain stimulation

Question 49

L-DOPA

Answer 49

- dopamine precusor that helps to alleviate symptoms - initially effective - 50% of patients develop DOPA-induced dyskinesia after 5-10 years

Question 50

DOPA-induced dyskinesia

Answer 50

- involuntary erratic movements - result of L-DOPA treamtent for 5-10 years

Question 51

deep brain stimulation

Answer 51

high frequency deactivate subthalamic nucleus

Question 52

increased activity of ? in parkinson's

Answer 52

subthalamic nucleus

Question 53

huntington's disease causes

Answer 53

- progressive atrophy of the striatum - genetic

Question 54

huntington's disease treatment

Answer 54

- xenazine - antidepressants/antipsychotic drugs

Question 55

xenazine

Answer 55

- suppresses involuntary movements - multiple side effects (drowsiness, restlessnes, psychiatric conditions)

Question 56

why does huntington's disease have antidepressants/antipsychotic drugs as a treatment

Answer 56

high comorbidity rates

Question 57

output nuclei of basal ganglia are inhibitory/excitatory

Answer 57

inhibitory

Question 58

how does cortex signal to striata to disinhibit the thalamus

Answer 58

- output nuclei maintain a high tonic level of discharge (suppresses activity) - phasic decrease in firing rate releases target regions from inhibition - strong tonic inhibitions allows basal ganglia to regulate

Question 59

voluntary motor control of basal ganglia

Answer 59

- procedural learning (routine behavior/habits) - eye movement - cognition - emotional function

Question 60

which functions of basal ganglia use loops

Answer 60

- voluntary motor control - movement initiation - movement regulation - procedural learning (routine behavior/habits) - cognitive functions - emotional functions - eye movements

Question 61

basal ganglia motor loop

Answer 61

- putamen circuit - learned movement

Question 62

basal ganglia cognitive loop

Answer 62

- caudate circuit - cognitive control of motor pattern sequence - motor intentions

Question 63

cognition

Answer 63

thinking process using sensory input with info already stored in memory

Question 64

basal ganglia limbic loop

Answer 64

- give motor expressions to emotions - smiling, aggressive, submissive posture

Question 65

basal ganglia occulomotor loop

Answer 65

voluntary eye movement