Lecture 13: Cerebellum and Brainstem Deep Structures Flashcards
What are the 4 main functions of the cerebellum?
- Acts as a “comparator” that compensates for error in movement by comparing intention with performance.
- Involved with the coordination of somatic motor activity, the regulation of muscle tone, and mechanisms that influence and maintain equilibrium.
- Contributes to non motor functions such as cognition, emotion, and affective processing.
- Plays a role in sequencing incoming sensory patterns and detecting temporal changes in the sequence of sensory events.
What does the vermis and paravermian part of the cerebellum control?
Axial Musculature (neck and trunk muscles)
What do the lateral hemispheres of the cerebellum control?
Limbs (arms and legs)
What does the flocculonodular lobe of the brain do?
It is heavily involved in maintaining balance.
What are the pathways for the superior cerebellar peduncle ?
AFFERENT: Anterior Spinocerebellar Tract, Acoustic and Optic Information
EFFERENT: Dentarubrothalamic Tract, Dentatothalamic Tract
What are the pathways for the middle cerebral peduncle?
AFFERENT: Pontocerebral Tract
EFFERENT: none
What are the pathways for the inferior cerebellar peduncle?
AFFERENT: Vestibulocerebral Tract, Olivocerebellar Tract, Posterior Spinocerebellar Tract
EFFERENT: Cerebellovestibular Tract, Cerebelloolivary Tract
What type of cells are in the outer molecular layer of the cerebellar gray matter?
Basket and Stellate Cells
What type of cells are in the middle layer of the cerebellar gray matter?
Purkinje Cells
What type of cells are in the granule layer of the cerebellar gray matter?
Golgi and Granule Cells
What are the only output neurons of the cerebellar cortex?
Purkinje Cells
Where does the only direct input to the Purkinje Cells from outside the cerebellum come from?
climbing fibers that have their origin in the olivary nuclei
What cells have an inhibitory effect on Purkinje Cells?
Stellate and Basket Cells
What are the three functional divisions of the cerebellum?
- Vestibulocerebellum
- Spinocerebellum
- Cerebrocerebellum
What are the components of the vestibulocerebellum?
Vestibular nuclei, flocculonodular lobe, inferior portion of the paravermis, fastigial nuclei
What are the components of the spinocerebellum?
Anterior lobe, vermis, superior paravermis
What are the components of the cerebrocerebellum?
lateral portions of the posterior lobes
What is the function of the vestibulocerebellum?
Coordinate eye, head, neck movements and maintains balance.
What is the function of the spinocerebellum?
Coordinate trunk and proximal limb movements.
What is the function of the cerebrocerebellum?
- coordinate fine motor planning of limbs
- anticipate sensory consequences of the movements
- cognitive memory of motor movements
**Note that the RIGHT cerebellar hemisphere controls the RIGHT body, arm, and leg.
What are some of the clinical signs of cerebellar disease?
- Unstable gait and stance with a tendency to fall. Bored based gait (“sailor’s gait”, reeling and drunken)
- Movements are generally jerky and gunsmith and are accompanied by an intentional tremor.
- Ataxia (dis-coordination): trunk and/or extremities.
- Dysmetria of movement: goal-directed movement can over or undershoot the target.
- Eye Movement Disorders: nystagmus saccadic and smooth pursuit dysmetria
- Speech Disorders: ataxic dysarthria with scanning speech, difficulty to maintain speech rhythm, intention, and correct articulation.
Superior Colliculus
MIDBRAIN
Fuctions in the control of reflex movements that orient the eyes, head and neck in response to visual, auditory, and somatic stimuli
Periaquaductal Gray Matter
MIDBRAIN
Functions in the processing of autonomic and limbic activities, as well as modulation of nociception.
Aqueduct
MIDBRAIN
Passageway connecting the third and fourth ventricles.
Nucleus of Edinger-Westphal
MIDBRAIN
Parasympathetic innervation of the eye to constrict the iris and to the ciliary muscle to alter lens shape for accommodation.
CNIII nuclei and nerve
MIDBRAIN
Motor control of eye muscles