Cerebellum Flashcards
Develops from the rhombic lips of the metencephalon
Cerebellum
Lies in the posterior cranial fossa deep to the occipital bone and is separated from the cerebrum by the tentorium cerebelli
Cerebellum
The cerebellum has three anatomical lobes, which are the
Anterior, posterior, and flocculonodular lobe
The three anatomical lobes are divided by two fissures, the
Primary and posterolateral cerebellar fissures
The cerebellum has three functional vertical zones called the
Vermis, Paravermis (PV), and Hemisphere (H, also known as lateral) zones
The cerebellum has three pairs of deep nuclei called the
Fastigial, Interposed (globose and emboliform) and dentate nuclei
The cerebellum can be divided into subdivisions based on inputs. It is subdivided into
Spinocerebellum, cerebrocerebellum, and vestibulocerebellum
Inputs into the cerebellum have which type of organization?
“Fractured” topographic organization
Cerebellar zones and associated deep cerebellar nuclei are responsible for different functions and will influence different
Motor Pathways
Function in motor planning for extremities
Lateral Hemispheres
Function in distal limb coordination
Intermediate (paravermal) hemispheres
Functions in proximal limb and trunk coordination as well as balance and vestibuloocular reflexes
Vermis and flocculonodular lobe
The cerebellum is anchored to the brainstem by three peduncles called the
Superior, middle, and inferior peduncles
What are the three arteries that supply the cerebellum?
Superior cerebellar artery (SCA), anterior inferior cerebellar artery (AICA), Posterior inferior cerebellar artery (PICA)
Modifies motor commands to increase accuracy and allow adaptation of movements
Cerebellum
Functions in coordination of voluntary movements and fine motor control
Cerebellum
The cerebellum provides feedback, which is sensory information that is used to guide
Movement in real time
The cerebellum also provides a proactive process that uses experience to anticipate of a movement should be done. This is called
Feed forward
The cerebellum is closely aligned with motor performance, but it DOES NOT
Initiate movement or directly control musculature
“Fine tunes” motor output to make fluid movements but does NOT produce movement
Cerebellum
Located in the inferior and middle cerebellar peduncle
Inputs to the cerebellum
Signal moves from the cerebral cortex and synapses at the pontine nuclei before passing to the contralateral middle cerebral peduncle
Cerebrocerebellar tract
Functions to bring a copy of the planned efferent motor output (corticospinal tract)
Corticocerebellar tract
Brings afferent information about lower limb sensation to cerebellum
Dorsal Spinocerebellar Tract
Brings afferent information about upper limb sensation to cerebellum
Cuneocerebellar tract
Brings afferent information about balance, posture, and visual fixations to the cerebellum
Vestibulocerebellar Input
Functions in cerebellar motor learning and memory
Olivocerebellar Tract
The cerebellar cortex has 3 layers, each with different types of cells. What are the three layers?
Molecular layer, purkinje layer, and Granule layer
What are the three cell types in the molecular layer?
Stellate and basket cells, and purkinje dendrites
Which cells are in the purkinje layer?
Purkinje cells
Which cells are in the granule layer?
Granule and Golgi Cells
The general rule is that projections ascending are
Excitatory
The general rule is that projections descending are
Inhibitory
Will project to the deep cerebellar nuclei associated with their cerebellar cortex vertical zone
Purkinje Cells
Will then project out of the cerebellum to their respective places
Deep Cerebellar Nuclei
Outputs from the cerebellum are located in the
Superior cerebellar peduncle and the juxtarestiform body
Influence motor planning (premotor cortex)
Dentate nuclei
Influence the motor execution of distal limbs
Interposed nuclei
Influences motor execution of proximal limbs and trunk (motor cortex and brainstem)
Fastigial Nuclei
Functions to influence balance and ocular movements
Flocculonodular lobe & Inferior vermis
Bypasses the deep cerebellar nuclei
Flocculonodular lobe & Inferior vermis
Movements have a wavering course with truncal and/or appendicular
Ataxia
Nystagmus and movements that “over-shoot” or “undershoot” are characteristic of
Cerebellar lesions
Affect mainly distal limb coordination and motor planning
Lateral Cerebellar Lesions
Affect mainly trunk control, posture, balance and gait
Medial Cerebellar Lesions
Occur ipsilateral to lesion because cerebellar outputs decussate prior to the thalamus, then motor outputs decussate back to the original side (“double-cross”)
Deficits
Rare autosomal recessive neuro-degenerative disease with cerebellar ataxia, sensory loss, and muscle weakness
Friedreich ataxia
Involves degeneration spinocerebellar tracts (cerebellar ataxia), DCMLS (loss of vibration and proprioception) and LCST (UMN symptoms)
Friedreich ataxia
General ataxia, gait ataxia, affects legs > arms, broad based- staggering gait
Anterior lobe syndrome
Anterior lobe syndrome is caused by
Toxin ingestion
Causes Thiamine (B1) deficiency (Wernicke-Korsakoff syndrome) memory impairment, confusion, gait ataxia and oculomotor disorders (nystagmus)
Anterior lobe syndrome
