Lecture 20

Question 1

Makes up basal ganglia

Answer 1

-5 interconnected nuclei deep within center of the brain:
-caudate
-globus pallidus
-putamen
-sub-thalamic nucleus
-substantia nigra

Question 2

Describe caudate nucleus

Answer 2

-follows C-shaped structure of the lateral ventricles
-elfs hat
-Wider in anterior portion (head) and tapers through body (middle portion) into a tail
-medial to caudate is thalamus

Question 3

Describe location of the internal capsule

Answer 3

-surrounding caudate nucleus and medially thalamus
-cellular bridges- projections laterally through caudate that poke through internal capsule- connect caudate nucleus to other basal ganglia

Question 4

Identify and describe two segments of globus pallidus

Answer 4

-Externus (GPe)- external/lateral
-Internus (GPi)- more medial

Question 5

Describe location of globus pallidus

Answer 5

lateral to internal capsule: capsule, internus, externus on top

Question 6

Describe location of subthalamic nucleus

Answer 6

located below the thalamus at teh junction with the midbrain

Question 7

Describe putamen

Answer 7

-most lateral nuclei of basal ganglia
-lateral to globus pallidus externus
-cellular bridges from caudate nucleus connect directly with putamen

Question 8

Describe location of substantia nigra

Answer 8

-located in midbrain below sub-thalamic nuclei
-dorsal to cerebral peduncles
-ventral to red nucleus
-dark pigmentation due to dopaminergic neurons

Question 9

Describe segments of substantia nigra

Answer 9

-ventrally= pars reticulata
-dorsal= pars compacta

Question 10

Describe layers of basal ganglia

Answer 10

moving laterally: thalamus, caudate nucleus, internal capsule, globus pallidus (internus), globus pallidus (externus), putamen

Question 11

Nuclei that make up the striatum

Answer 11

caudate and putamen

Question 12

Nuclei that make up lentiform nucleus

Answer 12

putamen and globus pallidus

Question 13

Structures medial to internal capsule

Answer 13

caudate and thalamus

Question 14

Structures lateral to internal capsule

Answer 14

globus pallidus and putamen

Question 15

Describe cortical inputs to the basal ganglia

Answer 15

-inputs from entire cerebral cortex project to striatum: 4 channels/types of info through basal ganglia

-motor channel to control movements
-oculomotor channel: controlling eye
-prefrontal channel: cognition from frontal lobe
-limbic channel: associated with emotional procressing

-Motor and somatosensory areas project mainly to putamen, other aspects of processing involve caudate

Question 16

Describe inputs to the striatum

Answer 16

-3 key inputs:
-from entire cortex (ipsi side)
-substantia nigra pars compacta: influences can be both excitatory and inhibitory (on ipsi side)
-thalamus (ipsi side): all excitatory inputs

Question 17

Outputs from basal ganglia

Answer 17

-globus pallidus internus or from substantia nigra pars reticulata to: thalamus (primary output), reticular formation. superior colliculus (eye- for oculomotor channels)

Question 18

Describe how information travels via ouputs from basal ganglia

Answer 18

-like a funnel
-After outputs travel to thalamus they project back to cortex on same side and regions that info originated from.

Cortical/Internal loop from cortex to basal ganglia and back to cortex via thalamus
E.g. motor areas project to basal ganglia on ipsilateral side, gets processed and outputs via globus pallidus inturnus and substantia nigra pars reticulata to thalamus on same side and to back to cortex
-info coming in largest of nuclei: and caudate (striatum)
-processed in these basal ganglia nuclei and comes out globus pallidus internus

-Thalamic/ Other loop: inputs from thalamus to striatum out to globus pallidus internus and back to the thalamus

Question 19

Role of basal ganglia

Answer 19

Role in higher level processing and reinforce movements and action that are coming form the cortex