Basal Ganglia Dysfunction Flashcards
Function of the Basal Ganglia
Critical link b/w the idea of movement and the expression of movement
Indirect influence on motor action before the initiation of movement
Role in:
- Movement/Posture
- Perception and cognition
Function of BG in movement and posture
- Movement initiation and preparation
- Movement taht occur without external cues
- Movement execution time
- Response set
- Postural adjustment before distal movements
Role of BG in perception/Cognition
- Sensory integration
- spatial perception interpersonal/intrapersonal space
- behavior flexibility
- procedural learning (habits)
- complex learned tasks
Basal Gagnglia contains how many brain stem nuclei?
5
Dysfunction of the substantia nigra will lead to ________________
PD
Dysfunction of Caudate/Putamen will lead to _______________
HD
input/out of BG
input: cortex
output: thalamus
Name of the Pathways used by the BG to perform its function & function of each
Direct Pathway: thalamic excitation
Indirect Pathway: thalamic inhibition
Normal Function of the BG
Balance b/w Direct/Indirect Pathways
with thalamic disinhibition => cortical excitation
subthalamic disinhibition => decreased cortical excitation
Lesion of the direct pathway will lead to:
- loss of net thalamic excitation
- indirect pathway intact (thalamic inhibition)
- net effect: cortical inhibition
- ex: PD
Lesion of the Indirect pathway will lead to:
- Loss of net thalamic inhibition
- Direct pathway still intact: thalamic excitation
- net effect cortical excitation
- ex: HD, chorea, athetosis
Lesions of the BG will lead to
dyskinesia
no dysfunction of UMN/LMN systems (no paralysis or sensory changes)
no loss of will or knowledge needed to perform motor acts (they still know how to do something, but bdoy won’t cooperate)
Hypokinesia
lack of spontaneity
slowing of voluntary movements
Hyperkinesia
Involuntary spontaneous movements (chorea, ballismus, Tics, Athetosis)
example of Tics
Clearing throat all the time
eye twitch
