Basal Ganglia & Cerebellum Flashcards
Function of basal ganglia
Function of cerebellum
initiation of movements
modulation of on going movements/ motor learning
Why do we say cortex is reciprocally connected with both basal ganglia & cerebellum?
because cerebellum & basal ganglia both influence on cortex and vice versa
Via what do basal ganglia & cerebellum influence the motor cortex?
thalamus
Via what does the motor cortex influence cerebellum?
Tell 5 nuclei of basal ganglia & what part of 5 primary vesicles brains are they belonged to?
Caudate, putamen, globus pallidus (externus & internus) : of telencephalon
Subthalamic nucleus: of diencephalon
Substantia nigra: of midbrain
Where are the inputs that each component of globus pallidus receives from?
both globus pallidus receive inputs from striatum
only GPi receives input from subthalamic nuclei
Globus pallidus externus (GPe) _______ subthalamic nucleus
Globus pallidus internus (GPi) ______ subthalamic nucleus
project
receive projections
What structure does substantia nigra modulate?
the output of striatum
Striatum
Why is it called striatum?
Where is the input that it receives from?
caudate & putamen
because they are functionally identical
motor cortex
What are two components of substantia nigra?
Degeneration of what component that can cause Parkinson’s disease?
Substantia nigra pars compacta (SNpc) -> Parkinson’s disease
Substantia nigra pars reticulate (SNpr)
Which structure is the major output nucleus of basal ganglia?
How does this structure influence motor cortex?
globus pallidus internus (GPi) inhibit the thalamus -> no thalamic input to premotor cortex -> inhibition of movement
What does subthalamic nucleus do to GPi, when it is activated?
excite GPi when subthalamic activated
Which is the major input nuclei of basal ganglia?
striatum (caudate & putamen)
Why does denegeration of substantia nigra pars compacta (SNpc) lead to Parkinson’s disease?
because it will lack of dopamine neurotransmitter, which is important for initiating movements
What component of substantia nigra that is reciprocally interconnected with caudate & putamen?
What component of substantia nigra that involves in control of head & eye movement?
SNpc
SNpr
What structure modulate the output of striatum?
the output of globus pallidus?
substantia nigra
subthalamic nucleus
Describe the steps in initiating movements
- Cortex activates striatum
- Striatum inhibits GPi
- GPi stop inhibiting thalamus
- thalamus fires & excites premotor cortexs to initiate movements
What does GPi do to thalamus, when it is activated?
inhibit
When GPe activated, subthalamic _____ (activated/ inhibited)?
What will happen to the initiation of movements?
inhibited
the movement initiation speed up due to the increased activation of cortex
Describe the steps in inhibition of movement
- cortex excites striatum
- striatum inhibits GPe
- GPe stops inhibiting subthalamic nucleus
- subthalamic nucleus activates GPi
- GPi inhibits thalamus
- No thalamic inputs to the premotor cortex
Tell all the effects of activated & inhibited GPe to the cortex
- activated GPe inhibits subthalamic nucleus -> GPi receives no input & stop inhibiting thalamus -> increase activation of premotor cortex
- inhibited GPe stops inhibiting the subthalamic nucleus -> GPi activated & inhibit thalamus -> no initiation of movement
During initiation of movement, striatum ______ GPi?
During inhibition of movenent, striatum ____ GPi?
inhibit GPi directly & indirectly
excite GPi indirectly
What are the effects of dopamine on direct & indirect pathway for modulating initiation movements?
excites the direct pathway
inhibit the indirect pathway
Explain the effects of Dopamine exciting the direct pathway
Striatal neurons with D1 receptors excites neurons that inhibit GPi -> no inhibition inputs from GPi to thalamus -> increase the activation of premotor cortex
Explain the effect of dopamine on the indirect pathway
striatal neurons with D2 receptors inhibit neurons that inhibit GPe -> GPe is activated & inhibit subthalamic nucleus -> GPi is dormant -> no inhibition of thalamus -> increase activation of premotor cortex
What is the other name for negative signs - dysfunction of basal ganglia?
What is the other name for positive signs - dysfunction of basal ganglia?
hypokinetic
hyperkinetic
What are the symptoms of hypokinetic disorders?
Akinesia
Bradykinesia
Masked facies
dystonia
Parkinson’s disease
bradykinesia
akinesia
dystonia
slowness of movement
lack of movement
involuntary muscle contractions
masked facies
mask-like facial expression, infrequent blinking/ reptilian stare
gait
the pattern of limb movement
What are the hyperkinetic disorders?
lead-pipe/ plastic rigidity
cog-wheel rigidity
athetosis
dystonia
chorea
Ballismus
Huntington’s disease
Tourette syndrome
hypokinetic disorders
Why does it occur?
loss of motor function
the direct pathway is inhibited while indirect pathway is active -> thalamus is more inhibited -> reduced motor activity
lead-pipe/ plasticity
cog-wheel regidity
the uniform resistance to limb passive stretches
ratchet-like resistance to limb passive stretches
athetosis
inability to maintain a fixed or sustained posture
slow, involuntary, convoluted, writhing movements of fingers, hands, toes & feet
chorea
involuntary arrhythmic movements, forceful, rapid & jerky
What does Substantia nigra pars reticulate (SNpr) involve in?
control of head & eye movements
ballismus
violent flinging of the limbs
What are the three white matter bundle that serve as information highways connecting the cerebellum to brainstem?
inferior cerebellar peduncle
middle cerebral peduncle
superior cerebellar peduncle
What does inferior cerebellar peduncles do?
connect cerebellum to medulla
carry the ascending fibers tract from spinal cord to anterior lobe of cerebellum & the massive projections of climbing fibers from inferior olive
What does middle cerebella peduncles do?
carry the input fibers from pons & cortex to cerebellum (primarily posterior lobe/ lateral hemispher)
What does superior cerebellar peduncles do?
the primary major output tract of cerebellum
What are the cerebellar nuclei, which contain cell bodies of output neurons of each of the cerebellar lobes?
fastigial nuclei
interposed nuclei
dendate nuclei
Location of fastigial nuclei in this figure?
purple box
in flocconodular lobe & parts of anterior lobe
Where is the interposed nuclei in this figure?
Where do you can find this in cerebellum?
red & green box
anterior lobe
interposed nuclei consists of _____ & ____?
globose nuclei & emboliform nuclei
What is the structure in orange box?
where can you find this in cerebellum?
dendate
posterior lobe of cerebellum
T/F: The interposed nuclei comprises the largest portions of cerebellar nuclei
False
It’s dendate nuclei in posterior lobe
What are the cerebellar inputs?
cortical input
direct sensory input
modulatory input
what are the components of cortical inputs to cerebellum?
premotor & motor cortex
primary & secondary somatosensory cortex
post parietal visual regions
What are the components of direct sensory inputs to cerebellum?
spinal cord
vestibular nuclei
What are the components of modulatory inputs to cerebellum?
inferior olive
locus ceruleus
raphei nuclei
What are the two pathways involve in sending direct sensory inputs to cerebellum?
dorsal spinocerebellar pathways (lower body)
cuneocerebellar pathways (upper body)
Through ______ (inferior/middle/superior cerebellar peduncles) the direct sensory inputs travel to cerebellum
inferior cerebellar peduncle
Through ______ (inferior/middle/superior cerebellar peduncles) the cortical inputs travel to cerebellum
middle cerebellar peduncles
Through ______ (inferior/middle/superior cerebellar peduncles) the modulatory inputs travel to cerebellum
inferior cebrebellar peduncles
