BASAL GANGLIA Flashcards
(14 cards)
Structures
Striatum
Putamen
Caudate nucleus
Globus pallidus
Substantia Nigra (mid brain)
Subthalamic nucleus (subthalamic Region)
Basal Ganglia Functions
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
Basal Ganglia Pathways
Inhibitory neurotransmitter
* Dopamine
* _GABA__________
* Excitatory neurotransmitter
* ___Glutamete________
Basal Ganglia Pathways (Circuitry)
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
Direct Pathway
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
Indirect Pathway
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
Hypokinetic disorder
- __Parkinsonism/ Parkinson’s disease__________________________________
- Resting tremor
- Bradykinesia/akinesia
- Hypokinetic dysarthria
- Shuffling gait
- “masked” facial expression
- Cognition/affect: flat
Hyperkinetic disorders
Hyperkinetic disorders
* ____Huntington’s disease________________________________
* Involuntary movement: Chorea, Ballism
* Hyperkinetic Dysarthria
* Dysphagia
* Emotional & cognitive deficits
Gilles de la Tourette
Tics: uncontrolled speech and/or motor
behaviors
* coughs
* expletives
* words
* noises
* gross movements
* inhibition very difficult
* exacerbated by anxiety often
Speech, Language, and the Basal Ganglia
* Speech:
automatic movements for speech (imprecise
articulation, dysfluencies)
* regulate adjustments of movements
* inhibits extraneous speech/oral movements (lingual
tremor)
Speech, Language, and the Basal Ganglia
Swallowing :
inhibits extraneous oral movements (e.g., tremor in pts
with PD)
* adjustments to movements
Speech, Language and the Basal Ganglia
* Language:
modulates routinized, overlearned, automatic language
structures:
* formulaic language
* recited materials
* automatic speech
Treatments for PD
* Pharmacological approach
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
Surgical procedure
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…
