Basal Ganglia & Motor Control Flashcards
what structures form the lentiform nucleus?
putamen
globus pallidus I (externum)
globus pallidus II (internum)
what structures form the corpus striatum?
lentiform nucleus + caudate nucleus
name the 2 subdivisions of substantia nigra
pars compacta
pars reticulata
what structures form the ventral striatum?
head of caudate & putamen
what neurotransmitter is released from substantia nigra pars compacta?
dopamine
what neurotransmitter is released from substantia nigra pars reticulata?
GABA
Name the 4 basal ganglia
lentiform
caudate
subthalamic
substantia nigra
what is the most medial part of the ventral striatum?
nucleus accumbens
the nigrostriatal pathway sends dopamine from ____ to the ____
- substantia nigra pars compacta
- basal ganglia
the mesolimbic pathway sends dopamine from the ____ to the____
- ventral tegmental area
- parahippocampal gyrus & nucleus accumbens
the mesocortical pathway sends dopamine from ____ to the ____
- substantia nigra & ventral tegmental area
- prefrontal cortex
in the nigrostriatal pathway, the cerebral cortex projects to the ____ with ____ fibers
striatum
glutaminergic (+)
in the direct pathway, substantia nigra pars compacta projects to the ____ with ____ fibers
striatum
dopaminergic (+)
the striatum utilizes ____ interneurons for intercommunication
acetylcholinergic
in the direct pathway, the striatum projects to the ____ and ____ with ____ fibers
globus pallidus I & substantia nigra pars reticulata
GABAergic (-)
in the direct pathway, Globus pallidus I and substantia nigra pars reticulata project to the ____ with ____ fibers
ventral lateral & ventral anterior thalamic nuclei
GABAergic (-)
in the direct pathway, what is the ultimate action on the thalamus?
thalamus gets excited because GPI is inhibited from inhibiting thalamus
in the nigrostriatal pathway, the ventral anterior and ventral lateral thalamic nuclei project to the ____ with ____ fibers
supplementary & premotor cortex
glutaminergic (+)
excitation of the direct pathway results in…
excitation of motor cortex and initiation of movement
in the indirect pathway, substantia nigra pars compacta projects to the ____ with ____ fibers
striatum
dopaminergic (-)
in the indirect pathway, the striatum projects to ____ with ____ fibers
globus pallidus II
GABAergic (-)
in the indirect pathway, globus pallidus II projects to the ____ with ____ fibers
subthalamic nucleus
GABAergic (-)
in the indirect pathway, the subthalamic nucleus projects to ____ with ____ fibers
globus pallidus I & substantia nigra pars reticulata
glutaminergic (+)
in the indirect pathway, globus pallidus I & substantia nigra pars reticulata project to the ____ with ____ fibers
ventral lateral & ventral anterior thalamic nuclei
GABAergic (-)
in the indirect pathway, what is the overall effect on the ventral anterior & ventral lateral thalamic nuclei
VA & VL are inhibited from projecting glutaminergic neurons to supplementary & premotor cortex
excitation of the indirect pathway results in…
inhibition of motor cortex & stopping of movement
Hypokinetic disorders involve breakdown of the ____
direct pathway
Hyperkinetic disorders involve breakdown of the ____
indirect pathway
symptoms of hypokinetic disorders
akinesia
bradykinesia
symptoms of hyperkinetic disorders
dyskinesias (involuntary movements):
- chorea
- ballismus
- athetosis
- dystonia
what is the mechanism of Parkinson’s disease?
depletion of dopaminergic cells in substantia nigra causing breakdown of nigrostriatal pathway
symptoms of Parkinson’s disease
- Akinesia (trouble starting movement)
- Bradykinesia (slow voluntary movement)
- Resting tremor
- Cogwheel or lead pipe rigidity
- Flexed posture
- Mask-like facial expression
- Shuffling & impaired balance
Name 3 treatments of Parkinson’s disease
- L-DOPA precursor to dopamine
- Human embryonic dopamine cell transplant (stem cells)
- Pallidotomy (break globus pallidus I), GP I pacemakers, or thalamectomies
What is Huntington’s disease?
autosomal dominant hereditary disease with insidious onset in 4th-5th decade of life, resulting from slow degeneration of neurons in the striatum
symptoms of Huntington’s disease
- chorea (dance-like movements/involuntary twitching extremities & face)
- dementia (cognitive deterioration)
- behavioral or psychiatric disturbances
prognosis of Huntington’s disease
death 15-20 years after onset of disease
Sydenham’s chorea (St. Vitu’s Dance)
transient (reversible) childhood chorea associated with rheumatic fever and affecting the striatum
Athetosis
degeneration of globus pallidus resulting in slow, sinuous, writhing movements of distal extremities
Ballism
lesion of subthalamic nucleus or its connections resulting in contralateral involuntary movements of proximal extremities & trunk
Wilson’s disease
autosomal recessive disorder that results in abnormal metabolism of copper which progressively degenerates the liver and basal ganglia
Almost all patients with Wilson’s disease present with…
a Kayser-Fleischer ring in their corneas & aberrant movements
Dystonia Musculorum Deformans
rare hereditary condition associated with injury of lentiform nucleus, resulting in co-contraction
examples of focal dystonias include…
torticollis (traps & SCM contract constantly)
blepharospasm (upper eyelid spasm)
dysphonia (vocal cord spasm)
facial spasm
writer’s cramp
