Basal Ganglia

Question 1

how do the BG and cerebellum communicate with motor neurons

Answer 1

indirectly through the thalamus

Question 2

6 deep brain nuclei of basal ganglia

Answer 2

caudate
putamen
GPi
GPe
subthalamic nucleus
substantia nigra

Question 3

caudate + putamen form the….

Answer 3

striatum

Question 4

ventral striatum is also called the

Answer 4

nucleus accumbens

Question 5

putamen and GP form the…

Answer 5

lentiform nucleus

Question 6

subthalamic nucleus location

Answer 6

below thalamus and lateral to hypothalamus

Question 7

glutamate vs GABA

Answer 7

excitatory vs inhibitory

Question 8

2 outputs of the BG

Answer 8

GPi
SNr

Question 9

4 inputs of the BG

Answer 9

substantia nigra compacta (SNc)
caudate
putamen
subthalamic nucleus

Question 10

main neurotransmitter between cerebrum + BG inputs

Answer 10

glutamate

Question 11

what pathway is dopamine excitatory vs being inhibitory

Answer 11

ex = direct/GO
inhib = indirect/NO-GO

Question 12

is ACh excitatory or inhibitory? How about serotonin

Answer 12

ACh = excitatory
Serotonin = inhibitory

Question 13

main neurotransmitter for BG outputs

Answer 13

GABA

Question 14

where do SNr outputs go

Answer 14

superior colliculus + eye fields of premotor cortex and tectospinal tract

Question 15

what is the only ventral striatal pathway loop

Answer 15

emotion loop

Question 16

what 2 loops are part of the prefontal channels

Answer 16

goal-directed loop
social behavior

Question 17

goal-directed behavior loop pathway

Answer 17

lateral prefrontal cortex
v
head of caudate
v
GPi
v
thalamus
v
lateral prefrontal cortex

Question 18

function of goal-directed behavior loop

Answer 18

“adulting”
decision making + planning appropriate to circumstance

Question 19

deficits in goal-directed behavior loop can lead to…

Answer 19

poor decision making
inattention/bad concentration
disorientation
poor short term memory

Question 20

social behavior loop pathway

Answer 20

ventral prefrontal cortex
v
head of caudate
v
substantia nigra reticularis
v
thalamus
v
ventral prefrontal cortex

Question 21

function of social behavior loop

Answer 21

social cues, self-control, filter info to be relevant or irrelevant

Question 22

deficits in social behavior loop can lead to…

Answer 22

impulsiveness
indifference
angry/violent
risky behavior

Question 23

emotion loop pathway

Answer 23

medial prefrontal cortex
v
ventral striatum (putamen/caudate)
v
thalamus
v
medial frontal cortex

Question 24

function of emotion loop

Answer 24

reward seeking!!
motivation
link btwn emotional, cognitive, and motor systems

Question 25

deficits in emotion loop can lead to...

Answer 25

impaired reward seeking/addictions L BG stroke = depression/dulling emotions

Question 26

oculomotor loop pathway

Answer 26

frontal/supplementary eye fields v body of caudate v thalamus v frontal/supplementary eye fields

Question 27

function of oculomotor loop

Answer 27

- rapid eye movements like saccades/prosaccades/antisaccades - spatial attention - decides eye motions

Question 28

deficits in oculomotor loop can lead to....

Answer 28

poor saccadic eye movements

Question 29

motor loop pathway

Answer 29

motor + premotor cortex v putamen v GP v thalamus v motor + premotor cortex

Question 30

function of motor loop

Answer 30

regulates muscle contraction/force muli joint movements movement sequencing

Question 31

which loop does NOT involve the caudate

Answer 31

motor loop

Question 32

disinhibition requires __ inhibitory neurons + ___ target neurons

Answer 32

2 1

Question 33

what is disinhibition important for

Answer 33

fine tuning movement

Question 34

all 3 motor loop pathways use ____ as their output nucleus

Answer 34

GPi

Question 35

what is the role of GPi in the motor loop internal pathways

Answer 35

it inhibits motor thalamus which excites cortical motor areas

Question 36

stop pathway (hyperdirect)

Answer 36

motor cortex --> excites subthalamic nucleus --> excites GPi --> inhibits motor thalamus inhibits motor programs and stops irrelevant movements

Question 37

go pathway (direct)

Answer 37

motor cortex --> excites putamen --> inhibits GPi --> motor thalamus is less inhibited specific movements are facilitated due to less inhibition imposed on motor thalamus

Question 38

no-go pathway (indirect)

Answer 38

motor cortex --> excites putamen --> inhibits GPe --> subthalamic nucleus is LESS inhibited --> excites GPi --> inhibits motor thalamus inhibition of unwanted movements

Question 39

what is the only motor loop pathway to use GPe?

Answer 39

no-go pathway

Question 40

neurons that compose 95% of the striatum

Answer 40

medium spiny neurons (aka spiny projection neurons)

Question 41

medium spiny neurons

Answer 41

GABA-like inhibitory cells within the striatum

Question 42

D1 receptors + where are they found

Answer 42

dopamine excites inhibitory neurons in GPi found in direct (go) pathway

Question 43

D2 receptors + where are they found

Answer 43

dopamine inhibits GPe, thus, disinhibiting subthalamic nucleus and stimulating GPi found in indirect (no-go) pathway

Question 44

dopamine regulates _____________ from GPi

Answer 44

tonic inhibition

Question 45

what structure sends inputs to the putamen D1 and D2 receptors

Answer 45

substantia nigra compacta (SNc)

Question 46

motor loop regulates motor function through 3 pathways...

Answer 46

motor thalamus (voluntary motor) pedunculopontine nucleus (posture/proximal limb activity) midbrain locomotor region (walking)

Question 47

where are stepping pattern generators located

Answer 47

midbrain

Question 48

hypokinetic disorder

Answer 48

parkinson's

Question 49

what is the most common BG disorder

Answer 49

parkinson's

Question 50

hyperkinetic disorders

Answer 50

huntingtons dystonia tourettes CP

Question 51

GPi's role in parkinsons

Answer 51

overactivity of GPi due to decreaesd dopamine from SNc

Question 52

affects of GPi inhibition of motor thalamus, pedunculopontine nucleus, and midbrain locomotor region in parkinson's

Answer 52

MT = brady/hypokinesia PPN = activation of reticulospinal tract --> rigidity of postural + girdle muscles MBLR = freezing and festinating gait

Question 53

choreiform movements

Answer 53

involuntary, continuous, + ballistic movements of the limbs

Question 54

what disease are choreiform movements found

Answer 54

huntington's disease

Question 55

affects of an inhibited GPi of motor thalamus, pedunculopontine nucleus, and midbrain locomotor region in huntington's disease

Answer 55

MT = excited motor thalamus (involuntary mvmt) PPN = loosey goosey postural/girdle muscles MBLR= unknown

Question 56

what happens in huntington's disease to the BG

Answer 56

90% of GABA inhibitory neurons are lost in the putamen and caudate this leads to less GPe (no-go) input, thus lossing the excitation of the subthalamic nucleus on the GPi basically, GPi cannot inhibit motor thalamus

Question 57

dystonia

Answer 57

involuntary sustained muscle contractions, causing abnormal posture, twisting, and repetitive movements "looks painful"

Question 58

writer/musician's cramps are examples of _________

Answer 58

focal dystonia