lecture 7 basal ganglia

Question 1

what are the five major nuclei of the basal ganglia?

Answer 1

• caudate nucleus
• putamen
• globus pallidus- internus and externus
• subthalamic nuclei
• substantia nigra

Question 2

what two nuclei make up the striatum?

Answer 2

caudate nucleus and putamen

Question 3

what two nuclei make up the lenticular nucleus?

Answer 3

putamen and globus pallidus

Question 4

where does the caudate nucleus run?

Answer 4

runs with the lateral ventricle

Question 5

where is the lenticular nucleus?

Answer 5

deep to the insula

• putamen- most lateral, joined to caudate head at the ventral striatum (includes nucleus accumbens)
• globus pallidus- pointed medially

Question 6

where is the substantial nigra located?

Answer 6

2 parts in the rostral midbrain, between the cerebral peduncles and the red nuclei

• compacta
• reticularis

Question 7

where is the sub thalamic nuclei located?

Answer 7

inferior to the thalamus

Question 8

what the functions of the basal ganglia nuclei?

Answer 8

• muscle contraction regulation: force, multi joint coordination, sequencing, imitation of learned sequences of movement
• input from cortex

Question 9

true or false the direct circuit is inhibitory to the cortex

Answer 9

false the direct circuit excites the cortex

Question 10

true or false the indirect circuit inhibits the cortex

Answer 10

true

Question 11

what are the 3 primary inputs in the circuitry?

Answer 11

• premotor and sensorimotor cortex to putamen to globus pallidus internus to ventrolateral thalamus
• cortex to caudate to globus pallidus internus to ventrolateral thalamus
• subthalamic nuclei to globus pallidus to ventrolateral thalamus

Question 12

what are the 2 primary outputs to the circuitry?

Answer 12

• globus pallidus- GABA inhibitory n. via ansa lenticularis and lenticular fascicles bundles to thalamus
• substantia nigra reticularis- GABA inhibitory to thalamus

Question 13

what 5 types of neurotransmitters can be found in the basal ganglia?

Answer 13

• glutamate
• GABA
• Substance P
• Enkephalins
• Dopamine

Question 14

what are the two types if dopamine receptors and where do the originate?

Answer 14

originate in the substantia nigra

• D-1: excites the direct path
• D-2: inhibits the indirect path

Question 15

True or false: both D-1 and D-2 impact the different paths by increases excitation to the cortex

Answer 15

TRUE

Question 16

where is the nucleus accumbens?

Answer 16

where the head of the caudate and anterior putamen meet

Question 17

what is the nucleus accumebens?

Answer 17

collection of GABA inhibitory cell that connect with

• globus pallidus>dorslamqdial thalamus> prefrontal cortex
• substanita nigra and pontine reticular formation

Question 18

where does the nucleus accumbens get input from?

Answer 18

amygdala and ventral tegmentum

Question 19

what are the roles of the nucleus accumbens?

Answer 19

• drug addiction via increased dopamine in cells
• musical effects on emotion
• rhythmic timing
• depression

Question 20

What are positive signs and list 7 examples

Answer 20

positive signs are involuntary muscle contractions; something you can see
Examples:
-resting tremor
-rigidity
-chorea
-dyskinesia
-dystonia
-athetosis
-ballism

Question 21

what are negative signs and list 2 examples

Answer 21

negative signs are lack of muscles contractions; things you can’t see
Examples:
-bradykinesia
-hypokinesia/ akinesia

Question 22

what is a resting tremor?

Answer 22

positive sign: rhythmic oscillations

Question 23

what is rigidity?

Answer 23

positive sign: increased resistance to movement in all muscles, hypertonicity

Question 24

what is chorea?

Answer 24

positive sign: continuous rapid movements (degradation of the caudate nucleus seen in Huntington’s)

Question 25

what is dyskinesia?

Answer 25

positive sign: involuntary movement during a voluntary action

Question 26

what is dystonia?

Answer 26

positive sign: involuntary sustained muscle contraction

Question 27

what is athetosis?

Answer 27

positive sign: writhing movements (stratal lesions)

Question 28

what is ballism?

Answer 28

positive sign: fast movement of whole limbs (lesions of contralateral sub thalamic nuclei)

Question 29

what is bradykinesia?

Answer 29

negative sign: slow movements

Question 30

what is hypokinesia or akinesia?

Answer 30

negative sign: few or no movement (reduced dopamine from substantia nigra to stratum- parkinson's) - lead pipe rigidity - cog- wheel rigidity

Question 31

what two structure degenerate in Parkinson's?

Answer 31

substantial nigra and pedunculo pontine nuclei

Question 32

what are the 2 signs or Parkinson's?

Answer 32

- hypokinetic- movement freezing, postural instability, reduced imitation of movement - hyperkinetic- rigidity, resting tremors

Question 33

what are the 3 treatments for Parkinson's?

Answer 33

- L dopa - Deep brain stimulation, ablation, or neuronal transplants/ stem cells - Optokinetic triggering for smoother movement patterns

Question 34

what are the 2 causes of Huntington's?

Answer 34

- hereditary | - degernation of striatum and cortex

Question 35

what are the signs of Huntington's?

Answer 35

- hyperkinetic- continuous movement in dancelike or writhing patterns - hallucinations - outbursts - depression

Question 36

what are the 2 treatments for Huntington's?

Answer 36

- management of psychological changes - medications to slow progression rate, control motor symptoms, block excitotoxins that disrupt energy metabolism of cells

Question 37

what are the 2 pathologies for dystonias?

Answer 37

- genetic: focal, involuntary sustained contractions | - acquired: overuse

Question 38

what are the symptoms of dystonias?

Answer 38

- cramping | - movement decomposition, decreased isolation of digits

Question 39

what are the two treatments for dystonias?

Answer 39

- pharmacological: botox | - acquired: responsive retraining