BASAL GANGLIA

Question 1

Structures

Answer 1

Striatum
Putamen
Caudate nucleus
Globus pallidus
Substantia Nigra (mid brain)
Subthalamic nucleus (subthalamic Region)

Question 2

Basal Ganglia Functions

Answer 2

Regulates and modifies movements that began in
cortex : Does not initiate movement!
* Connections with thalamus (to send info up to cortex)
* Regulates motor patterns that became automatic
over time

Question 3

Basal Ganglia Pathways

Answer 3

Inhibitory neurotransmitter
* Dopamine
* _GABA__________
* Excitatory neurotransmitter
* ___Glutamete________

Question 4

Basal Ganglia Pathways (Circuitry)

Answer 4

Inhibitory or excitatory effects on thalamus
* Circuitry
* DIRECT: facilitation of cortical activity (making movement)
* INDIRECT: suppression of cortical activity (preventing
unwanted movement)
* Striatum: inhibitory
* Globus pallidus internal/substantia nigra: inhibitory
* Globus pallidus external: normally inhibitory
* Subthalamic nucleus: excitatory to GP-i/SNr complex
* Thalamus: excitatory
* Cortex: excitatory

Question 5

Direct Pathway

Answer 5

Goal: Facilitation of cortical activity
* Motor excitatory projections from cortex to
caudate/striatum (glutamate)
 Increases activity of striatum:
Sends inhibitory signal to SN(pars reticularis)-GP(internal)
via (GABA): normally inhibitory
 Thalamus less inhibited
Sends excitatory signal to cortex (glutamate)
 Primary motor cortex sends excitation signal to
muscle

Question 6

Indirect Pathway

Answer 6

Goal: Suppression of cortical activity
* Motor projections from cortex (excitatory, glutamate) to striatum
 Caudate/striatum sends inhibitory to GP-external (GABA)
 Less inhibits subthalamic nucleus (STN)
 Less inhibited STN: stimulates the SN-GP-internal complex
(glutamate)
 Increased excitation of SN-GP, which then increases inhibition of
the thalamus (GABA)
 Thalamus is less able to release excitatory signal on cortex (less
glutamate)
 Muscles receive fewer excitatory impulses, reduced movement

Question 7

Hypokinetic disorder

Answer 7

• __Parkinsonism/ Parkinson’s disease__________________________________
• Resting tremor
• Bradykinesia/akinesia
• Hypokinetic dysarthria
• Shuffling gait
• “masked” facial expression
• Cognition/affect: flat

Question 8

Hyperkinetic disorders

Answer 8

Hyperkinetic disorders
* ____Huntington’s disease________________________________
* Involuntary movement: Chorea, Ballism
* Hyperkinetic Dysarthria
* Dysphagia
* Emotional & cognitive deficits

Question 9

Gilles de la Tourette

Answer 9

Tics: uncontrolled speech and/or motor
behaviors
* coughs
* expletives
* words
* noises
* gross movements
* inhibition very difficult
* exacerbated by anxiety often

Question 10

Speech, Language, and the Basal Ganglia
* Speech:

Answer 10

automatic movements for speech (imprecise
articulation, dysfluencies)
* regulate adjustments of movements
* inhibits extraneous speech/oral movements (lingual
tremor)

Question 11

Speech, Language, and the Basal Ganglia
Swallowing :

Answer 11

inhibits extraneous oral movements (e.g., tremor in pts
with PD)
* adjustments to movements

Question 12

Speech, Language and the Basal Ganglia
* Language:

Answer 12

modulates routinized, overlearned, automatic language
structures:
* formulaic language
* recited materials
* automatic speech

Question 13

Treatments for PD
* Pharmacological approach

Answer 13

Treatments for PD
* Pharmacological approach
* Replace dopamine with synthetic precursor
to it “L-dopa”
* Levodopa does NOT reverse symptoms or
degenerative changes that have taken place
in the cells

Question 14

Surgical procedure

Answer 14

Surgical procedure
* ____________________________
* Implanting electrodes into BG structures and sends
electrical impulses
* Appears to “halt” the disease or slow progression
* Electrical impulses at steady frequency  lesion effect
* Reduce tremor
* Improve bradykinesia, shuffling…