Basal Ganglia Flashcards
The direct striatomedial pallidonigral pathway is activated by _________ projections from the sensorimotor cortex and by ___________nigral (pars compacta) -striatal projections.
Activation of this direct pathway inhibits the ___________ which in turn disinhibits the __________ and _________ nuclei of ________. As a cpmsequence, thalamocortical druve is enhanced and cortically initiated movements are faciliated
The direct striatomedial pallidonigral pathway is activated by glutaminergic projections from the sensorimotor cortex and by dopaminergic nigral (pars compacta) -striatal projections.
Activation of this direct pathway inhibits the medial pallidum which in turn disinhibits the ventrolateral and ventroanterior nuclei of thalamus. As a cpmsequence, thalamocortical druve is enhanced and cortically initiated movements are faciliated
The indirect circuit arises from ______ neurons that contain ________ and smaller amounts of enkephalin. These striatal projections have an ________ effect on the ________ pallidum, which in turn disinhibits the _____________ thru GABA release provinding _________ drive to the _________ pallidum and _____________. The net effect is _____________ that reduces thalamocortical input to the precentral motor fields and impedes involuntary movement.
The indirect circuit arises from putaminal neurons that contain GABA and smaller amounts of enkephalin. These striatal projections have an inhibitory effect on the lateral pallidum, which in turn disinhibits the subthalamic nucleus thru GABA release providing subthalamic drive to the medial pallidum and substantia nigra pars reticulata. The net effect is thalamic inhibition that reduces thalamocortical input to the precentral motor fields and impedes involuntary movement.
T/F
Enhanced conduction thru the indirect pathway leads to hypokinesia by increasing pallidothalamic inhibition whereas enhanced conduction thru the direct pathway results in hyperkinesia by reducing pallidothalamic inhibition.
True
p67
is the NT of the excitatory projections from the cortex to the striatum and of the excitatory neurons of the subthalamic nucleus
Glutamate
is the inhibitory NT of the striatal, pallidal, substantia nigra PR projection neurons
GABA
highest concentration of Acetylcholine, as well as enzymes necessary for synthesis and degradation is in the
striatum
T/F
Dopamine can be inhibitory or excitatory depending on the site of action and subtype of dopamine receptor
True
p69
Dopamine receptors and location
D1 and D2 - striatum
D3 - nucleus accumbens
D4 - frontal cortex, limbic structures
D5 - hippocampus
hemiballismus attributed to lesions in
subthalamic nucleus of Luys
Basal Ganglia
a common associated behavioral abnormality is abulia in patients with lesions in
caudate
clinicopathologic correlations of extrapyramidal movement disorders
Identify principal location of morbid anatomy
Unilateral plastic rigidity with rest tremor
contralateral substantia nigra
clinicopathologic correlations of extrapyramidal movement disorders
Identify principal location of morbid anatomy
unilateral hemiballismus and hemichorea
contralateral subthalamic nucleus of Luys or luysial-pallidal connections
clinicopathologic correlations of extrapyramidal movement disorders
Identify principal location of morbid anatomy
chronic chorea of huntington type
caudate nucleus and putamen
clinicopathologic correlations of extrapyramidal movement disorders
Identify principal location of morbid anatomy
athetosis and dystonia
contralateral striatum
clinicopathologic correlations of extrapyramidal movement disorders
Identify principal location of morbid anatomy
cerebellar incoordination, intention tremor, hyptonia
ipsilateral cerebellar hemisphere
ipsilateral middle or inferior cerebellar peduncle
brachium conjunctivum
