Basal ganglia Flashcards
5 nuclei
caudate putamen globus pallidus substantia nigra subthalamus
corpus striatum
caudate+putamen+globus pallidus
striatum
caudate+putamen
GABA
lenticular or lentiform nucleius
putamen+ globus pallidus
nucleus accumbens
special area functionally - connected with limbic system and plays a role in addiction
anterior are where caudate and putamen are continuous ventrally
globus pallidus internal segment
major output of corpus striatum
projects to the VA/Vl nuclei of the thalamus via the lenticular fasciculus and ansa lenticularis
inputs- striatum, GPe, subthalamic nucleus
uses GABA
globus pallidus external segment
receives inputs from striatum
outputs to GPi and subthalamus
uses GABA
pars compacta
cell dense portion
substantia nigra
dopamine
contain neuromelanin - gray/black color
pars reticulata
substantia nigra
GABA
subthalamic nucleus
ventral to thalamus
connected to striatum and substantia nigra
glutamate
corticostriate
glutamate
thalamocortical
glutamate
parkinsonism
loss of dopaminergic inputs to striatum from substantia nigra leads to lack of movement akinesia with hypertonia difficulty initiating movements cog-wheel rigidity tremore-at-rest festinating gait expressionless mask
cholinergic neurons
in striatum
excite indirect pathway and inhibit direct pathway
net decrease in movement
chorea
loss of cholinergic interneurons in striatum
loss of inhibition of direct pathway and loss of control of the indirect pathway
excessive, unwanted, uncontrollable movements
involve distal extremities, tongue, face
irregular, brisk, jerky
basal ganglia function
planning voluntary motor movements
crucial in initiation and early processing
influences outputs of motor cortical areas despite no connection to LMNs
damage
motor distrubances- tremor/involuntary movements change in tone/posture slowness of movements neuropsychological issues
putamen inputs
sensorimotor cortical
head of caudate inputs
prefrontal cortex
tremor-at-rest
pill-rolling
dyskinesia
fingers, hand and forearm
tremor present during inactivity and disappears during sleep and movement
athetosis
dyskinesia
slow writhing movements of neck, trunk, extremities
worm-like
ballism
subthalamic lesion
contralateral
large flailing movements of extremities involving proximal m.
