Lecture 8 Basal Ganglia

Question 1

What are the major structures that make up the basal ganglia?

Answer 1

• striatum (caudate and putamen)
• globus pallidus
• substantia nigra
• subthalamic nuclei

Question 2

What structures make up the striatum?

Answer 2

caudate and putamen

Question 3

Which structures receive the majority of input for the basal ganglia?

Answer 3

striatum (caudate and putamen)

Question 4

Which structures project the majority of output from the basal ganglia?

Answer 4

globus pallidus (internal and external) and substantia nigra (pars compacta and pars reticularis)

Question 5

Describe the major motor and non-motor functions of the basal ganglia.

Answer 5

Motor

• initiation and execution of movement
• prevention of unwanted movements
• modulates incoming info from motor cortex and improves it

Non-motor

• eye movement loop
• goal-directed behavior loop
• social behavior loop
• emotion loop
• prediction of events, selecting desired/undesired movements, motor learning

Question 6

Who are the major sources of input to the striatum?

Answer 6

• cerebral cortex (all but 1st order visual and auditory cortices)
• Substantia NIgra Pars Compacta (internal thinking)
• Thalamus
• Subcortical structures

Question 7

What makes up the corticostriatal pathways?

Answer 7

• all of cerebral cortex except 1st order visual and auditory cortices
• majority: frontal and parietal association areas

Question 8

Where does the major outputs go from the basal ganglia?

Answer 8

• ventral lateral and anterior nuclei of thalamus - go to frontal lobe
• intralaminar nuclei of thalamus
• mediodorsal nucleus
• reticular formation (pons, medulla)
• superior colliculus

Question 9

What neurotransmitters are used in direct and indirect pathway of basal ganglia function?

Answer 9

inhibitory - GABA

excitatory - Glutamate

Question 10

What information is relayed through oculomotor loop?

Answer 10

• higher control of eye movements - aids in spatial attention
• initiate fast eye movements toward an object

Question 11

What information is relayed through goal-directed behavior loop?

Answer 11

• decision to choose a motor plan that will result in something positive
• decision making; goal directed behavior; planning; action selection; learning

Question 12

What information is relayed through social behavior loop?

Answer 12

• recognize social cues; regulate self control; evaluates what info is relevant and irrelevant
• ex: how tightly you squeeze your hand in a handshake

Question 13

What information is relayed through limbic loop?

Answer 13

• regulate and modulate limbic system (emotion)
• links emotions to cognitive and motor systems; reward seeking; outcome predictions
• Important with significant psychiatric conditions such as schizophrenia but also plays in an important role in drug addiction

Question 14

What are the regulators of the thalamus that inhibit it from sending motor signals non-stop?

Answer 14

Globus pallidus internus and substantia nigra pars reticulata

Question 15

What sends dopamine to the striatum? What does this do?

Answer 15

• substantia nigra - pars compacta
• excites striatum for direct pathway or inhibits striatum for indirect pathway (gives thalamus more free range to facilitate movement)

Question 16

What is the role of Ach?

Answer 16

• inhibits dopamine when appropriate to quickly interrupt ongoing motor behavior in response to adverse environmental stimuli

Question 17

Which non-motor loop receives dopaminergic input from ventral tegmental area

Answer 17

limbic/emotion loop