week 8

Question 1

What is the function of the basal ganglia?

Answer 1

unconscious motor system, regulates muscle force, multijoint movement, and sequencing of movement
influences muscle tone

Question 2

What are the pathways of the basal ganglia?

Answer 2

motor pathway-projects to supplemental, premotor, and primary motor cortex
occulomotor pathway-frontal eye fields
prefrontal pathway-cognition
limbic pathway-emotions and motivation

Question 3

what are the structures of the BG

Answer 3

lentiform nucleus-putamen, globius pallidus
striatum-caudate, putamen
nucleus accumbens-junction of caudate and putamen anteriorly

Question 3

anatomy of the basal ganglia

Answer 3

caudate,putamen,globius pallidus,subthalamic nucleus, substantia nigra

Question 4

What is the input nuclei?

Answer 4

receive afferent connections from 4 lobes of the cerebum
structures: caudate, putamen, nucleus accumbens

Question 5

what is the intrinsic nuclei?

Answer 5

project to input and output nuclei
structures: globus pallidus external segment, subthalamic nucleus, substantia nigra pars compacta (dopamine to striatum)

Question 5

what is the output nuclei?

Answer 5

project to: frontal lobe
pedunculopontine nucleus (medially descending motor tracts)
mesencephalic locomotor region (MLR) (stepping pattern generators)

structures: globus pallidus internal segment, substantia nigra pars reticulata

Question 6

Output circuitry for motor thalamus pathway

Answer 6

BG->motor thalamus->motor cortex(frontal lobe)->corticospinal tracts->LMNs->voluntary muscle

Question 7

output circuitry of pedunculopontine tract

Answer 7

BG->pedunculopontine nucleus (lateral tegmentum ventral to inf. colliculus)->reticulospinal and tectospinal tracts->LMNs->postural and girdle muscles

Question 8

output circuitry pathway midbrain

Answer 8

midbrain->reticulospinal tracts->stepping pattern generators->LMN walking

Question 9

Direct pathway net effect

Answer 9

facilitation

Question 10

indirect pathway net effect

Answer 10

inhibition

Question 11

Neurotransmitters of BG

Answer 11

GABA-inhibitory to output nucleii
Dopamine-substantia nigra to striatum
Glutamate-cortex to putamen
acetylcholine-striatal interneurons

Question 12

Direct pathway structures

Answer 12

Cortex->striatum->globus pallidus internal/substantia nigra->thalamus

Question 13

indirect pathway structures

Answer 13

cortex->striatum->globus palladis external->subthalamic nucleus->globus pallidus internal/substantia nigra->thalamus