basal ganglia Flashcards
what nuclei make up the striatum
putamen and caudate
what structure separates the nuclei of the striatum
internal capsule
what is the functional significance of the striatum
major input from the cortex
what is the function of the caudate nuclei
eye movement and congition input from the cortex
what is the function of the putamen
motor input from the cortex
which part of the substantia niagra is input/output
input: pars compacta
output: pars reticulata
what structures make up the lenticular nucleus
putamen
globus pallidus
what three structures make up the corpus striatum
caudate nucleus
putamen
globus pallidus
what is the function of nucleus accumbens
emotion and limbic input
what two tracts does the medial segment of globus pallidus internus give rise to and where do they pass relative to internal capsule
lenticular fasciculus - passes through posterior limb of IC
ansa lenticularis - passes under posterior limb of IC
what is the thalamic fasciculus
where lenticular fasciculus and ansa lenticularis come together and go to the thalamus
what is the general scheme of input/output of the basal ganglia
cerebral cortex => striatum => output nuclei => thalamus => back to cortex
what is the function of the direct motor pathway of basal ganglia
execute intended movement through disinhibition
what is the function of the indirect motor pathway of basal ganglia
inhibit extraneous motor pathways
what is the general scheme of the oculomotor loop
FEF => caudate => SNr and GPi => VA/MD => FEF
what is the general scheme of the associative loop
prefrontal/premotor => caudate => SNr and GPi => VA/MD
what causes hyperkinetic disorders
not enough inhibition from the indirect motor pathway
what is chorea
spontaneous, rapid, jerky involuntary movements
what is athetosis
continual slow movements
what is ballismus and what is it caused by****
flailing movement of whole extremity
caused by lesion of contralateral subthalamic nucleus **
what is dystonia
persistent/fixing of posture
is huntington dz hyper- or hypokinetic
hyperkinetic
what is sydenham chorea
temporary chorea causes by untreated group A strep
do lupus erythmatous and thyrotoxosis cause hyper or hypokinetic disorder
hyperkinetic
what is the cause of huntington’s dz
degeneration of neurons in striatum and cerebral cortex => decreased GABA
how is huntington’s treated
with seratonin antagonist tetrabenzine
what are the sxs of huntington’s dz
involuntary, rapid jerking movements
dementia
unsteady gait
grimacing movements
is parkinson’s dz hyper- or hypokinetic
hypokinetic
do wilson’s dz and CO/Mn poisoning cause hyper or hypokinetic disorder
hypokinetic
what causes hypokinetic disorders
too little direct pathway effect from basal ganglia
what is the physiologic cause of parkinson’s
SNc does not release enough dopamine onto basal ganglia
what are the sxs of parkinson’s dz
resting tremor slow movement shuffling gait cogwheel rigidity dementia
how is parkinson’s treated
L-dopa
