Basal ganglia Flashcards
what happens if the motor cortex is damaged
will cause paralysis or spacisity
is the moto cortex direct or indirect out put
direct
what spinal tract is the motor cortex linked to
corticospinal
what type of information does the cerebellum receive
afferent from the spinal cord
what is caused when the cerebellum is damaged
inaccurate or poorly timed movement / ataxia
the cerebellum does what
modulates/ regulates movement accuracy
what does the basal ganglia do
controls the strategic aspects of movement
what type of movement is the basal ganglia responsible for
involuntary movements like- tremors, chorea ( jerking), and athetosis (abnormal muscle contraction )
the basal ganglia is connected to the spinal cord - T or F
false
what does damage to the basal ganglia result in
problems in initiating and terminating movement
what is the differences between basal gaglia and cerebellum
BG - widespread connections to the cerebral cortex via thalamus / not just involved with movement/ is linked to behavior and emotion
Cerebellum - connections onto to sensorimotor areas of cerebral cortex/ receives info from the brainstem and spinal cord and is involved only with movement
how many nuclei are there in the basal ganglia
5
what are the 5 names of the BG
Caudate
putamen
globus pallidus - internal and external
subthalamic nucleus - STN
substantia nigra - pars compacta and pars reticulata
what is a striatum
is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain.
what are the main 2 of the striatum
Putamen and Caudate
what is the largest nuclei in BG
Caudate and putamen
what type of information does the striatum receive
direct and indirect via the thalamus - connections from the cerebral cortex
which nuclei does the striatum project to
globus pallidus and substantia nigra both through the striatonigral pathway
STN - subthalamic nuclei forms indirect pathway between what
GPE and SNr
GPI and SNR are the what of the basal ganglia
out put centre
what does the output Centre do in the BG
send inhibitory signals to the thalamus
where does the output from GPI and SNR go
the thalamus
The BG recieves excitatory input from the Cerebral cortex which sends signals to the …. which what..
thalamus - suppressing the motor cortical activity
excessive basal ganglia input results in…
slow movement and reduced input results in enhanced moveemnts
what is the transcortical loop
a loop of connections between 3 key parts for movement
the loop is made of what
cerebral cortex , BG and thalamus
what is the first step in the loop
striatum, and putamen, receives vast array of inputs from the cerebral cortex - motor and sensory
what step in the loop is this - striatum, and putamen, receives vast array of inputs from the cerebral cortex - motor and sensory
1
what is the second step in the loop
output of GPI and SNr project to thalamus - an inhibitory signal
what step in the sequence is this - output of GPI and SNr project to thalamus - an inhibitory signal
2
what step in the loop is this - Inhibited thalamus projects motor cortex thus suppressing the movement
3
what is the 3rd step in the loop
Inhibited thalamus projects motor cortex thus suppressing the movement
what are the 3 neurotransmitters
excitatory - glutamate - open arrows
inhibitory - GABA- filled arrows
mixed - dopamine - mixed arrows
what is the thalamus receiving
inhibitory signals from BG
What type of neuroT. Is used in the direct pathway - resulting in disinhibition and resulting in facilitating movement
2 inhibitory signals
what does indirect pathway involve
excitation of inhibition thereby supressing movement
direct pathway means
movement
indirect pathway means
suppressed movement
Where does dopamine come from
SNc
dopamine can effect in what 2 ways
excite in the direct path
inhibit in indirect pathway
what does it depend on what effect dopamine has
which receptor it binds too
what effect does dopmine have
disinhibits thalamic output thereby facilitating movement
parkinsons is caused by what
increased activation of indirect pathway and decreased activation of direct pathway causing movement to be supressed
what is huntingtins caused by
decreased activation of indirect pathway and increased activation of direct pathway - movement is facilitated
what type of cells do Parkinson’s lose
dopaminergic cells in substantia nigra
parkinsons symptoms
bradykinesia - slow movement
akinesia - inability to initiate movement
rigidity
tremor
postural instability
parkinsons treatments
deep brain stimulation, disrupting the STN, inhibits indirect pathways thereby inhibiting thalamic inhibition
symptoms of Huntington’s
rapid, jerky motions with no clear purpose
is huntingtons caused by a gene in selective atrophy of striatum
true
is parkinsons hypo or hyper kinetic
hypo
is huntingtons hypo or hyper kinetic
hyper
dopaminergic cells are lost in which disease
parkinsons
atrophy of striatum is in which disease
huntingtons
