Lecture 3 And 4 - Cerebellum And Basal Ganglia Flashcards
More than ___ neurons in your brain are in the cerebellum
50%
What is the cerebellum responsible for?
Quality control
When an UMN talks to a LMN, how does the cerebellum find out about it?
A cope of the motor command is sent to the cerebellum
How does the cerebellum find out about the result of the motor response?
Proprioceptive info sent to the cerebellum
How does the cerebellum send feedback to the motor cortex?
Cerebellum compares the command to the actual motion based on the proprioceptive info and the copy of the motor command
Where is the white matter on the cerebellum? How about the gray matter?
White inside grey outside
What are the different segments of the cerebellum?
Anterior lobe, primary fissure, posterior lobe, horizontal fissure, vermis (the lil dick)
Where is the flocculonodular lobe?
Above the posterolateral fissure, basically the lil segment
What is the functional name of the flocculonodular lobe?
Vestibulocerebellum
What is the flocculonodular lobe in charge of?
Balance and eye movements
What are the inputs of the flocculonodular lobe?
Vestibular nuclei (inner ear)
Where are the outputs of the flocculonodular?
Fastigial nuclei and vestibular nuclei, then lower motor neurons
Where is the anterior lobe of the cerebellum?
…anterior ig lol
What is the functional term of the anterior lobe?
Spinocerebellum
What is the anterior lobe in charge of?
Movement coordination, motor execution
What are the inputs and outputs of the anterior lobe?
Input: Proprioception
Output: interposed nuclei then to descending motor pathways
Where is the posterior lobe?
Posterior lol
What is the functional name of the posterior lobe?
Cerebrocerebellum or neocerebellum
What are the inputs and outputs of the posterior lobe?
Input: cortex
Output: dentate nucleus then to thalamus and cortex
Where is the fastigial nucleus?
Most medial and dorsal of the deep nuclei, biggest
Where is the interposed nuclei?
Just ventral of the fastigial nuclei
Where is the dentate nuclei? What does it look like
Dorsal of the interposed nuclei, lil squiggly lines
What is the only nuclei that matters for this test?
Dentate
What are the three peduncles?
Superior, middle, inferior
Is superior afferent of efferent?
Efferent mostly
Is middle afferent of efferent?
Mostly afferent
Is the inferior peduncle efferent or afferent or both?
Both
Summarize the three peduncle jobs as questions
Superior: how can i adjusts my movements to get there? Error signal
Middle: where do i want to be? Copy of command
Inferior: where am i? Proprioception
What are the three layers of the cerebellar cortex?
Molecular layer, purkinje layer (barrier to deepest), granular layer (deepest)
What are the three neuron types in the cerebellum?
Granule cells
Purkinje cells
Inhibitory neurons (basket cells Stellate cells and golgi cells)
What are the two types of input in the cerebellum?
Both are excitatory
- climbing fibers from inferior olive
- mossy fibers from spinal cord, cortex via pons (input to granule cells, info about voluntary movements)
Explain the “climbing the olive tree”
Climbing fibers go up the inferior olive, wrap around purkinje cells and excite them, granule cell receives input from mossy fiber (which gets info from cortex) to stop them if a mistake occurred
What is the Marr-Albus-Ito motor learning theory?
Granule cells give continuous info about what the body is doing and when the body makes a movements error, climbing fiber fires, kicking of parallel fiber synapses
What’s the basal ganglias main job?
Selecting the best cortical output
What does the brain count as best?
Most practiced and most likely to be rewarded
What are the nuclei of the basal ganglia?
Caudate nucleus (next to lateral ventricle)
Putamen (outermost thing outside internal capsule)
Globes pallidus (one more in than putamen)
Subthalamic nucleus (underneath lateral ventricle)
Substantial Nigra (the dark thing far below the lateral ventricle)
Nucleus accumbens (just below lateral ventricle)
Where do the different parts of the thalamus send outputs to in the cortex?
Ventral posterior lateral nucleus sends output to primary sensory cortex
Ventral lateral and ventral anterior send output to motor areas and receive input from basal ganglia
Does the caudate nucleus appear smaller or bigger from a coronal view and you move more posterior to the brain?
Smaller, its the biggest near the front of the brain
Where is the putamen from a coronal view as you go posterior to the brain?
Always stays on the outside of the internal capsule
Where can you see the putamen from a lateral view?
Posterior to the caudate nucleus
Can you see the globes pallidus in a very anterior coronal cut of the brain?
Nope
Where can you see the globes pallidus in a coronal cut of the brain?
A bit in the center where you can see the GP internal being more lateral than the GP external and it being right next to the putamen
Where is the nucleus accumbens?
Right below the lateral ventricles
What elements are in the basal ganglia GO pathway?
Cortex, striatum (caudate + putamen), substantia nigra, brainstem and spinal cord, thalamus, and GP internal
Describe the GO pathway
Cortex excites striatum
Substantia either excites or inhibits striatum
Striatum inhibits GP Internal
GP internal can no longer inhibit the thalamus
Thalamus is super excitatory and without inhibition it excites the cortex
The cortex then excites the brainstem and spinal cord
Describe the stop pathway
Cortex excites striatum
Substantia nigra regulates striatum
Striatum inhibits GP external
GP external cant inhibit GP internal anymore
GP internal inhibits thalamus
Thalamus no longer excites cortex
Describe the motor loop
GO: M1 -> Putamen -> thalamus -> S1
STOP: M1 -> Putamen -> inhibit thalamus
Describe the cognitive loop
GO: Association cortex -> Caudate & Nucleus accumbens -> Thalamus -> Cerebellum
STOP: Association cortex -> caudate & NA -> INHIBIT THALAMUS
Describe the limbic loop?
Limbic system -> caudate and NA -> thalamus -> limbic
Limbic system -> caudate and NA-> INHBIT THALAMUS
What does Huntington’s disease target?
Striatum is targeted
What does Parkinson’s disease?
Kills substantia nigra
Huntingtons too much GO or STOP?
GO
Parkinson’s too much GO or STOP?
STOP
