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
Spinothalamic tract
MIDBRAIN
Fiber pathways to the thalamus for pain/temp form the periphery.
Medial Lemniscus
MIDBRAIN
Sensory pathway for proprioception connecting the nucleus gracilis and cognates with the thalamus
Medial Geniculate
MIDBRAIN
thalamic relay nuclei for auditory information.
Lateral Geniculate
MIDBRAIN
thalamic relay nuclei for visual information.
Cerebral Peduncle
MIDBRAIN
Fiber bundles of the corticospinal tract connecting the cerebral cortex to the brainstem.
Optic Tract
MIDBRAIN
Optic fibers from optic chiasm to the lateral geniculate.
Substantia Nigra
MIDBRAIN
one of several nuclei involved in smooth muscle control
**Degenerates in Parkinson’s Disease.
Red Nucleus
MIDBRAIN
Relay between the cerebellum to the thalamus.
Medial Longitudinal Fasciculus
MIDBRAIN
Fiber pathway between the vestibular nuclei and the CN nuclei III, IV, VI to coordinate head/eye movements.
Superior Cerebellar Peduncle
PONS
Fiber pathway to and from the cerebellum.
Middle Cerebellar Peduncle
PONS
Fiber pathway to and from the cerebellum.
Mesencephalic, Main Sensory Nucleus, Motor Nucleus of CNV
PONS
three nuclear components of the trigeminal nerve nuclei
CNV
PONS
Motor and sensory fibers of CNV
Pontine Nuclei
PONS
collection of neurons in the pons that receives input from the neocortex and sends crossing fibers through the middle and cerebrellar peduncle.
Locus coeruleus
PONS
a nonadrenergic brainstem nucleus involved in mood and the sleep/wake cycle.
Raphe nucleus pontis
PONS
one of several serotonin nuclei involved in mood and the sleep/wake cycle
Corticospinal Tract
PONS
motor fibers from the neocortex to spinal interneurons and lower motor neurons.
Inferior and Medial Vestibular Nuclei
UPPER MEDULLA
Nuclei of the vestibular system that regulates balance
Nucleus and Tractus Solitarius
UPPER MEDULLA
Sensory nucleus from taste (CNVII), glands, and chemo/baroreceptors (CNIX and CNX)
Dorsal Motor Nucleus Vagus (CNX)
UPPER MEDULLA
Parasympathetic motor nucleus to the lungs and gut.
Spinal Nucleus and Tract of CNV
UPPER MEDULLA
nuclear and tract components of CNV that extends down into the upper cervical spinal cord
Inferior Olivary Nucleus
UPPER MEDULLA
origin of the climbing fibers to the cerebellar parking cells
Pyramid
UPPER MEDULLA
name given to the corticospinal tract fibers in the medulla
Reticular Formation
UPPER MEDULLA
a network of neurons and axons that reside in the brain stem tegmenjtum involved in arousal, respiration and heart control
Nucleus of CNIX (in the lower medulla)
LOWER MEDULLA
Glossopharyngeal nucleus with motor control over tongue and pharyngeal muscles with taste
Weber’s Syndrome
REGION: midbrain (base)
ARTERIAL SUPPLY: tip of basilar artery and/or branches of the PCA.
STRUCTURES INVOLVED: CNIII fasicles and Cerebral Peduncle
CLINICAL SIGNS/SYMPTOMS: Ipsilateral 3rd nerve paresis and contralateral hemiparesis.
Claude’s Syndrome
REGION: midbrain (tegmentum)
ARTERIAL SUPPLY: tip pf the basilar artery and/or branches of the PCA
STRUCTURES INVOLVED: CNIII fasicles, red nucleus, superior cerebellar peduncle.
CLINICAL SIGNS/SMPTOMS: Ipsilateral 3rd nerve paresis, Contralateral tremor, Contralateral ataxia.
Benedikt’s Syndrome
REGION: midbrain (base and tegmentum)
ARTERIAL SUPPLY: tip of the basil artery and/or branches of the PCA.
STRUCTURES INVOLVED: CNIII fasicles, red nucleus, superior cerebellar peduncle, substantia nigra
CLINICAL SIGNS/SYMPTOMS: Ipsilateral 3rd nerve paresis, Contralateral hemiparesis, Contralateral tremor, Contralateral ataxia.
Millard-Gubler Syndrome
REGION: medial pons (base and tegmentum)
ARTERIAL SUPPLY: Paramedian branches of the basilar artery.
STRUCTURES INVOLVED: Corticospinal and Corticobulbar Tracts, CNVII fascicles.
CLINICAL SIGNS/SYMPTOMS: Contralateral hemiparesis, Ipsialteral LMN facial paresis.
Foville’s Syndrome
REGION: medial pons (base and tegmentum)
ARTERIAL SUPPLY: Paramedian branches of the basilar artery.
STRUCTURES INVOLVED: Corticospinal and Corticobulbar Tracts, CNVII fascicles, PPRF and/or CNVI.
CLINICAL SIGNS AND SYMPTOMS: Contralateral hemiparesis, Ipsialteral LMN facial paresis, Ipsialteral gaze paresis.
Gaze disorders
lesion in the medial longitudinal fasciculus
loss of discriminative touch, vibration, and conscious proprioception on the contralateral side of the body
lesion in the medial lemniscus
contralateral hemiparesis
lesion in the corticospinal tract
Medial Medullary Syndrome
REGION: Medial Medulla
ARTERIAL SUPPLY: Vertebral arteries, Paramed. Branches
STRUCTURES INVOLVED: Corticospinal Tract, Medial Lemniscus, CNXII
CLINICAL SIGNS/SYMPTOMS: Contralateral arm/leg weakness, Contralateral decrease in position/vibration, Ipsilateral tongue weakness
Wallenberg’s Syndrome (lateral medullary syndrome)
REGION: Lateral Medulla
ARTERIAL SUPPLY: Vertebral arteries or PICA
STRUCTURES INVOLVED: Vestibular nuclei, Inferior Cerebellar Peduncle, CNV and Tract, Spinothalamic Tract, Sympathetic fibers, Nucleus Ambiguous, Nucleus Solitarius
CLINICAL SIGNS/SYMPTOMS: Ipsialteral ataxia, vertigo, nausea, Ipsilateral decrease in face pain sensation, Contralateral decrease in body pain sensation, Ipsilateral Horner’s dysphagia.
Loss of pain and temp from ipsilateral side of the face
lesion in the spinal trigeminal nucleus and tract
dysarthria and dysphagia
lesion to the nucleus ambiguous
loss of pain and them to the contralateral side of the body
lesion to the spinothalamic tract
gait ataxia on the ipsilateral side of the body
lesion to the spinocerebellar tract