Basal ganglia

Question 1

what are the roles of the basal ganglia?

Answer 1

1. inhibit involuntary movements at rest 2. facilitate voluntary movements

Question 2

what are the five basal ganglia?

Answer 2

1. caudate nucleus 2. putamen 3. globus pallidus 4. subthalamic nucleus 5. substantia nigra or, corpus striatum + substantia nigra + subthalamic nucleus

Question 3

what makes up the lentiform nucleus?

Answer 3

putamen + globus pallidus

Question 4

what makes up the corpus striatum?

Answer 4

caudate + lentiform

Question 5

what makes up the striatum?

Answer 5

putamen + caudate nucleus

Question 6

the caudate is primarily concerned with what function?

Answer 6

cognitive

Question 7

the putamen is primarily concerned with what function?

Answer 7

motor

Question 8

what are the major inputs to the striatum?

Answer 8

1. corticostriate 2. thalamostriate 3. nigrostriatal

Question 9

what are the outputs from the striatum?

Answer 9

1. striatopallidal 2. striatonigral (pars reticulata)

Question 10

what are the inputs to the pallidum?

Answer 10

1. striatopallidal 2. subthalamic fasciculus

Question 11

what is the thalamic fasciculus?

Answer 11

1. the common tract joining the lenticular fasciculus + ansa lenticularis as they travel from the pallidum to the thalamus (VA and VL nuclei) 2. also carries cerebellar fibers to same nuclei

Question 12

what are the outputs from the pallidum?

Answer 12

1. pallidothalamic 2. pallidosubthalamic 3. pallidonigral 4. thalamocortical

Question 13

what are the “reciprocal connections” of the basal ganglia?

Answer 13

1. striatum - substantia nigra 2. pallidum - subthalamic

Question 14

what are the four loop circuits of the basal ganglia? what information do they convey?

Answer 14

1. motor - UMNs of corticospinal, corticonuclear tracts 2. association - planning and direction 3. oculomotor - integration of eye movements and visual guidance 4. limbic - emotional and motivational

Question 15

what is the conserved pathway of the loop circuits of basal ganglia?

Answer 15

cortex - striatum - pallidum - thalamus

Question 16

what are the roles of the VA / VL and mediodorsal nuclei or the thalamus?

Answer 16

1. VA / VL - relay signals related to movement 2. mediodorsal - relay signals to frontal and limbic cortex

Question 17

what is the direct pathway through the basal ganglia? what is the result?

Answer 17

1. facilitates flow of information through the thalamus 2. results in greater excitation of cortex, and voluntary movement (due to release of the thalamus from the tonic pallidal inhibition)

Question 18

what is the indirect pathway through the basal ganglia? what is the result?

Answer 18

1. decreases activity in the thalamus 2. lessens excitatory output to the cortex, and tonically suppresses inappropriate movements (also terminates volitional movements)

Question 19

what is the “input gate” to the basal ganglia?

Answer 19

striatum

Question 20

what is the “output gate” from the basal ganglia?

Answer 20

pallidum

Question 21

what serves as the interface between the basal ganglia and the cortex?

Answer 21

thalamus

Question 22

is the thalamus excitatory or inhibitory to the cortex?

Answer 22

excitatory

Question 23

is the pallidum excitatory or inhibitory to the cortex?

Answer 23

inhibitory

Question 24

what is the proximate cause of Parkinson’s disease?

Answer 24

death of dopaminergic cells in pars compacta of substantia nigra

Question 25

what is athetosis?

Answer 25

slow, involuntary, convoluted, writhing movements of fingers, hands, toes, and feet

Question 26

what is hemiballismus?

Answer 26

appearance of flailing, ballistic, undesired movements caused primarily by a decrease in activity in the subthalamic nucleus

Question 27

what is the nucleus accumbens?

Answer 27

when the caudate nucleus and putamen come together