L17 Cerebellum: Structure and Neurophysiology Flashcards
Lesions of the Cerebellum vs. Other Motor Processing Centers
Lesions in other motor processing centers=> PARALYSIS or INVOLUNTARY MOVEMENTS
Lesions in the CEREBELLUM => ERRORS in the movement of large numbers of muscles
Cerebellum:
○ ______% of brain volume but more than ______% of all neurons
○ _______x more inputs than outputs
□ Inputs: _______ and _____
□ Outputs:
- ___________________________
- ___________________________
- ___________________________
○ Adjusts motor output from ________ and _________
○ Plays a role in_____________________
Cerebellum:
○ 10% of brain volume but more than 50% of all neurons
○ 40x more inputs than outputs
□ Inputs: SENSORY and MOTOR
□ Outputs:
- Premotor Cortex
- Motor Cortex
- Brainstem
○ Adjusts motor output from CORTEX and BRAINSTEM
○ Plays a role in Motor Learning
The Brainstem forms part of the Roof of ______________________
- Connected to the closed part of MEDULLA by ______________________
- Connected to ________ of Midbrain by _________________________
The Brainstem forms part of the Roof of 4TH VENTRCLE
- Connected to the closed part of MEDULLA by POSTERIOR Medullary Vellum
- Connected to TECTUM of Midbrain by ANTERIOR Medullary Vellum
3 Lobes of the Cerebellum?
- Anterior (Top)
- Posterior (Bulk of Structure)
- Floccunlondular (Rolled Underneath)
Highly myelinated connection of cerebellum to PONS?
Peduncle
3 Functional Regions of Cerebellum?
Regional Specialization of the Cerebellum?
- Vestibulocerebellum
- Spinocerebellum
- Cerebrocerebelllum
Vestibulocerebellum
□ Vestibular Inputs to Flocculonodular Lobe
□ Balance and Eye Movements
Spinocerebellum
□ VERMIS: Visual, Auditory, Vestibular Input
- Posture
- Locomotion
- Gaze
□ INTERMEDIATE REGION: Somatosensory/proprioceptive input from limbs
Cerebrocerebelllum
□ LATERAL REGIN: Input From Cortex
Conscious Assessment of motor tasks
Somatotopic Maps in Cerebellum?
Nuclei of the Cerebellum and their functions?
Nucleus of the Cerebellum responsible for regulating balance and sending information to vestibular and reticular nuclei?
Fastigial Nucleus
Nucleus responsible for voluntary movement and sending axons to the Thalamus and Red Nucleus?
Dentate and Interposed Nuceli
3 Layers of the Cerebellum?
Molecular (Outer)
Purkinje (Middle): ONLY output neuron of the cerebllum
Granular (Inner)
3 Layers of the Cerebellum?
Molecular (Outer)
Purkinje (Middle): ONLY output neuron of the cerebellum
Granular (Inner)
Only Output Neuron of the Cerebellum?
Purkinje Axons are the ONLY output of the cerebellar cortex projecting to Deep Nuclei
(granular layer => cerebellar white matter => deep cerebellar nuclei)
Only excitatory neuron of the Cerebellum?
Granule Neurons (Glutamate)- Parallel Fibers
What does the Granular Layer of the Cerebellum contain?
Granular Layer (INNER):
§ Contains Golgi and Granule Cells (40-50% of all brain neurons)
§ Contains many MOSSY FIBERS
- Originate from nuclei in Spinal Cord and Brainstem
- Form synapses part of the Cerebellar Glomerulus
- Convey Sensory information from Periphery AND Cortical Signals
What does the Molecular Layer of the Cerebellum contain?
Molecular Layer (OUTER): Granule Cell axons bifurcate in molecular layer => parallel fibers form synapses with:
- Dendrites of Purkinje Cells
- Dendrite of Golgi, Stellate, and Basket Cell
What does the Purkinje Layer of the Cerebellum contain? (Excitatory/Inhibitory Inputs)
EXCITATORY Inputs on Purkinje Cells:
- Parallel Fibers (aka. Granule Cells)
- Mossy Fibers (Simple Spike)
- Climbing Fibers (Single Synapse, Complex Spike, Alters Mossy Fiber Response)
INHIBATORY Inputs of Purkinje Cells:
- Stellate Cells => Dendrites
- Basket Cells => Cells Bodies
Cerebellar Networks
○ Purkinje Neurons will Fire w/ a single input from a _______________
○ Excitatory input from __________________ is much weaker
○ ________________ also excite INHIBATORY_________________:
- Send their axons to neighboring rows of Purkinje neurons
- As ________________excite 1 row of Purkinje neurons => neighboring rows of Purkinje fibers are INHIBITED by these ______________
○ _______________ INHIBIT Mossy Fiber excitation of Granule Cells => shortens bursts of excitation
Cerebellar Networks
○ Purkinje Neurons will Fire w/ a single input from a Climbing Fiber
○ Excitatory input from Granule cells (parallel fibers) is much weaker (Summation of ~100 parallel fiber inputs across Purkinje cell dendrites needed)
○ Granule Cells also excite INHIBATORY Basket Cells
- Basket cells send their axons to neighboring rows of Purkinje neurons
- As Granule Cells excite 1 row of Purkinje neurons => neighboring rows of Purkinje fibers are INHIBITED by these Basket cells
○ Golgi Cells INHIBIT Mossy Fiber excitation of Granule Cells => shortens bursts of excitation
Information Processing in the Cerebellum
