Norden - Cerebellum Flashcards
The three lobes of the cerebellum are?
The anterior lobe
The middle lobe
The flocculonodular lobe
Has major connections w/ the vestibular and reticular formation.
Receives input from vestibular nerve. Coordinates reflexive equilibrium and balance via efferent connections w/ vestibular and reticular formation nuclei in the branistem
Flocculonodular lobe
Which cells are found in the mantle of the cerebellum?
Neuropil
Basket interneurons
Stellate interneurons
The cerebellum projects to ?
The. Nuclei of the indirect corticospinal system (Vestibular, reticular, and rubral nuclei) and to motor areas of the thalamus (VA/VL) which project to the cortex
The cerebellum develops from two germinal cell sources of ?
The alar plate
Cerebellar plate arised from ?
The ventricular zone of the neural tube
The deep cerebellar nuclei, purkinje cells, and golgi cells differentiate from. ?
The mantle layer
Which cell layers are the only ones which project out of the cerebellar cortex ?
The purkinje cell layer
The purkinje cells
Where does purkinje cell output go?
To the deep nuclei of the cerebellum?
What type of output do purkinje cells have?
ALL inhibitory output, except those from the flocculonodular lobe
What cells are in the granule cell layers?
High quantity of granule cells.
Less golgi internueons
Where do granule cells project?
Upward into molecular layer where they divide into parallel fibers to synapse w/ dendrites of the purkinje cells
What are the 4 deep nuclei of the cerebellum that lie immediately dorsal to the 4th ventricle ?
Fastigial nucleus
Globose nucleus
Emboliform nucleus
Dentate nucleus
Deep nucleus of cerebellum that sends efferents to the reticular and vestibular nuclei in the brainstem
Fastigial nucleus
Deep nuclei of the brainstem that pair function to send efferents to the red nucleus and motor nuclei of the thalamus (VA/VL)
Globose nucleus
Emboliform nucleus
Combine to make the interpositus nuclei of the cerebellum?
Globose and embolifrom nucleus
Sends the major outflow from the cerebellum to the red nuclei and the motor nuclei of the thalamus (VA/VL)
Dentate nucleus
The restiform body is /
Inferior cerebellar peduncle
The inferior cerebellar peduncle contains
Afferents from spinal cord and medullary areas:
Inferior olivary nucleus,
Cuneocerebellar, reticular formation nuclei, vestibular nerve/ nuclei
Efferents to the reticular and vestibular nucleis
Large afferent fiber bundle that connects the pons to the cerebellum
Middle cerebellar peduncle
Pontine nuclei cells make up the middle cerebellar peduncle and project to the _______ cerebellar cortex
Contralateral
This cerebellar peduncle projects major efferents from the interpositis and dentate nuclei to the contralateral thalamus and red nucleus
Superior cerebellar peduncle
The neurons of clarke’s nucleus get to the cerebellum how?
Through the ipsilateral dorsal spinocerebellar tract which enters the cerebellar via the ipsilateral inferior cerebellar peduncle.
Clarkes column carries non conscious proprioceptive infro from ?
C8 through L2
The ventral spinocerebellar tract enters the superior cerebellar peduncle and are the only afferent axons in this peduncle. Where are the first order neurons in this path?
The fasciculus gracilis of the CONTRALATERAL lumbosacral region
The spinal cord inputs to the cerebellum arise from which three areas?
Below L2
C8-L2
Above C8
The medullary input to the cerebellum comes from ?
Inferior olive
Vestibular formation nuclei
Reticular formation nuclei
All medullary input into the cerebellum travels through ?
The inferior cerebellar peduncle
Efferents of the cerebellum are?
To vestibular and reticular formation nuclei.
To red nucleus and thalamus
The afferents from the pontine nuclei pass through the middle cerebellar peduncle and enter the _____ cerebellar cortex
Contralateral
Climbing fibers originate where?
The inferior olive
Mossy fibers originate where?
Anywhere except the inferior olive
Involved in the coordination of ongoing movement of axial musculature
- Receives afferents from axial body regions via spinocerebellar and cuneocerebellar tracts, and the vestibular system
- Sends efferent axons to fastigial nucleus which then projects to vestibular and reticular formation nuclei
Vermal / meridian zone of cerebellum
What makes up the spinocerebellum?
The vermal and intermediate cerebellum
Involved in the coordination of ongoing movement of distal musculature
- Receives afferent sensory input from distal body regions via spinocerebellar and cuneocerebellar tracts
- Sends efferents to deep interpositus nuclei (globose and emmboliform) which then project out of the cerebellum via the superior cerebellar peduncle to the contralateral red nucleus and motor nuclei (VA, VL) of the thalamus
Intermediate (paramedian) cerebellum
Involved in the planning, sequencing and timing of learned, skilled motor movement; also plays a role in cognitive behavior (not well-understood at this point in time)
- Receives afferent input from the cerebral cortex via connections with pontine nuclei; note that pontine nuclei receive input from many cortical areas as well as some brainstem (e.g., superior colliculus) nuclei
- Efferents project to the dentate nucleus, which then projects via the superior cerebellar peduncle to the contralateral red nucleus and VA, VL of the thalamus
Lateral zone
Inability to articulate normally due to incoordination of movement of the tongu
Cerebellar dysarthria
Most common s/s of midline lesions of the cerebellum?
Truncal ataxia Wide based stance and gait Cerebellar dysarthria Ocular ataxia Nystagmus
Difficulty in the timing of movement. Happens pt’s w/ cerebellar hemisphere lesions. Pt will undershoot or overshoot when asked to touch two points in rapid succession in finger-to nose test
Dysmetria
Diifficulty in the timing and rhythm of movement.
Dysrhythmia
What are the s/s of cerebellar hemisphere lesions/
Ataxia (cannot walk in tandem, will fall towards side of lesions)
Dysmetria (difficulty in the timing of movement.)
Dysrhythmia
Tremor (specifically with action, worsens w/ finer movement required
Hypotonia
Lesions of the cerebellar hemisphere cause ____ symptoms
Contralateral
Lesions of the peduncels produce symptoms where?
Ipsilateral, contralateral, or bilateral
Infratentorial brain tumors, such as the vast majority of them, which is medulloblastoma, are more common in ?
Children
What is common presentation for medulloblastoma in children?
Medulloblastomas commonly arise at the vermis in children, so a common presentation is truncal ataxia.
What is a complication of medulloblastoma, due to where they sit ?
Non-communicating hydrocephalus.
These tumors can block the outflow from the 4th ventriclee
The most common cancers to metastasize to the brain are?
Lung, breast, and melanoma
Cerebellar hemorrhagic strokes are dangerous because ?
Transforaminal herniation and hydrocephalus are possible
In friedreich’s ataxia, what can happen to Clarke’s Nucleus?
Retrograde degeneration
Inheritance of Friedreich’s Ataxia
Autosomal recessive
degeneration of DRGs, peripheral nerves, dorsal and lateral areas of the spinal cord (including dorsal and ventral spinocerebellar tracts), cerebellar peduncles, and Purkinje neurons; Clarke’s nucleus may undergo retrograde degeneration
Freidreich’s Ataxia
Non-neurological signs/symptoms of Freidreich’s Ataxia?
Scoliosis, pes cavus, hypertrophic obstructive cardiomyopathy, diabetes
What happens in alcoholic degeneration of the cerebellum?
Degeneration fo the purkinje and granular cells which causes significant cellular atrophy and will lead to disequilibrium and ataxia
What is the clinical triad seen with the acute syndrome: Wernicke’s Encephalopathy ?
Cognitive dysfunction Ataxia Oculomotor abnormalities (opthalmoplegia and/ or nystagmus)
What do you typically give patients presenting with significant mental confusion of unknown entiology?
B1
To r/o wernicke’s encephalopathy
What is degenerated in wernicke’s encephalopathy?
Diencephalon (thalamus and mammillary nuclei)
Mibrain - periaqueductal gray and oculomotor nuclei
Cerebellum
When immune cells that are recruited to fight cancer turn and begin destroying the normal cells of the body?
Paraneoplasia ( in cerebellum this affects purkinje cells)
Clear cerebellar signs and symptoms without any abnormalities by imaging could indicate ?
Paraneoplasia
