Lopez- Cerebellar pathway summaries Flashcards
function of _____ pathway includes coordination/planning of voluntary movements
Cerebrocerebellum (lateral cerebellar hemisphere)
function of _____ pathway includes motor learning
Corticopontocerebellar Tract
function of____ pathway includes balance and posture and eye movements
Vestibulocerebellar pathway (Flocculonodular lobe)
function of _____ pathway includes regulation of muscle tone
Spinocerebellum (vermis and intermediate hemisphere)
function of _____ includes error correction in movements
inferior olivary nucleus and climbing fibers/purkinje cells
where is the lesion?
truncal ataxia, wide-based gait, vertigo, nystagmus, impaired VOR
Vestibulocerebellum (Flocconodular Lobe)
where is the lesion?
limb ataxia, intention tremor, dysmetria, scanning dysarthria
Cerebrocerebellum (lateral cerebellar hemisphere)
where is the lesion?
severe limb ataxia, intention tremor, difficulty with rapid alternating movements
Dentate Nucleus
where is the lesion?
gait ataxia, postural instability, hypotonia, dysarthria
Spinocerebellum (vermis and intermediate hemisphere)
where is the lesion?
ipsilateral cerebellar deficits, limb ataxia, tremor, dysdiadochokinesia (inability to perform rapid alternating movements)
superior cerebellar peduncle
where is the lesion?
ataxia, poor coordination of voluntary movements, hypotonia
middle cerebellar peduncle
where is the lesion?
ataxia, vestibular dysfunction, imbalance, vertigo, nystagmus
inferior cerebellar peduncle
where is the lesion?
hypertonia of extensor muscles, difficulty maintaining posture, increased fall risk
vestibulospinal tract (extensor control)
where is the lesion?
decreased upper limb flexor tone, impaired fine motor movements, mild postural instability
Rubrospinal tract (flexor control)
where is the lesion?
postural instability, difficulty initiating gait, abnormal locomotion
Reticulospinal tract (posture and locomotion)
in a patient with a lesion in the _____, the ipsilateral arm manifests an intention tremor while nearing the target
lateral cerebellar hemisphere
where is the lesion?
poor coordination of planned voluntary movements, impaired motor learning, limb ataxia
Corticopontocerebellar tract (cerebral input)
contains stellate cells, basket cells, parallel fibers, purkinje cell dendrites
molecular layer of cerebellar cortex
function: synaptic processing and inhibitory modulation
molecular layer of cerebellar cortex
function: single layer of Purkinje cells
Purkinje cell layer of cerebellar cortex
contains granule cells, golgi cells, unipolar brush cells, mossy fiber input
granular layer of cerebellar cortex
receives excitatory input and sends signals via parallel fibers
granular layer of cerebellar cortex
mossy fibers to granule cells to parallel fibers to purkinje cells is what pathway
indirect excitatory pathway
climbing fibers to purkinje cells is what pathway
direct excitatory pathway (LEARNING)
____ cells inhibit deep cerebellar nuclei, controlling motor output
Purkinje cells
functional component of cerebellum that deals with midline movements (gait, speech, walking, balance)
Vermis (red)
functional component of cerebellum that deals with reaching and grasping, hand to eye coordination
Paravermis (yellow)
functional component of cerebellum that deals with fine movements
cerebellar hemispheres (green)
part of cerebellum associated with coordinating balance and eye movements
Flocconodular lobe (blue)
axons of the cerebellar nuclei form cerebellar peduncles (name the nuclei)
lateral to medial
dentate, emboliform, globose, fastigial
lateral to medial
dentate, emboliform, globose, fastigial
intermediate zone (paramedian/paravermal)
yellow
median/vermal zone (red)
lateral zone
deals with the trunk
medial zone
deals with proximal limbs
paramedial zone
deals with face and distal limbs
lateral zone
deals with eye and vestibular movements
flocconodular lobe
Role in balance and eye movements [gaze stabilization].
Axial muscles for balance
Extraocular muscles for eye movement
Vestibulocerebellum (Flocconodular lobe)
Gross motor execution, coordination and postural stability.
Trunk Muscles
Proximal limb muscles
Spinocerebellum (vermis and paravermis)
Focuses on complex motor planning, cognition, and mental rehearsal.
Motor precision
Distal limb muscles for fine motor control
Cerebrocerebellum (cerebellar hemispheres)
degeneration of this lobe occurs in chronic alcoholism resulting in gait ataxia
anterior lobe (spinocerebellum)
lesion here results in prominent limb ataxia
posterior lobe (cerebrocerebellum)
a lesion here occurs due to medulloblastoma and results in nystagmus, eye movement abnormalities, vertigo, gait ataxia
Flocconodular lobe (vestibulocerebellum)
deals with efferent signals to thalamus
superior cerebellar peduncle
deals with sensory input from cerebellar cortex
middle cerebellar peduncle
deals with sensory input from spinal cord
inferior cerebellar peduncle
1
superior cerebellar peduncle
2
middle cerebellar peduncle
3
inferior cerebellar peduncle
afferent pathways
efferent pathways
carries proprioceptive info from lower extremities
“double crosser”
goes through superior cerebellar peduncle and ends on ipsilateral vermal/paravermal cortex
ventral/anterior spinocerebellar pathway
carries proprioceptive info from trunk and lower extremities
stays ipsilateral
goes through inferior cerebellar peduncle and ends on ipsilateral cerebellar cortex
dorsal/posterior spinocerebellar pathway
carries proprioceptive info from upper limb and thorax
stays ipsilateral
goes through inferior cerebellar peduncle
ends on ipsilateral cerebellar cortex
cuneocerebellar pathway
relays motor commands of cerebral cortex
enters through internal capsule and lands on pontine nucleus and then through middle cerebellar peduncle
ends on contralateral cerebellar cortex
corticopontocerebellar pathway
facilitates motor learning and error correction in movement (from cerebral cortex)
goes through internal capsule and onto inferior olivary nucleus through inferior cerebellar peduncle and ends on contralateral cortex
cortico-olivocerebellar pathway
comes from sensorimotor cortical regions of parietal lobe
goes through internal capsule and middle/inferior cerebellar peduncles
ends on ipsilateral cerebellar cortex
cerebroreticulocerebellar pathway
deals with balance and eye movements
goes from semicircular canals to CNVIII nuclei
through inferior and superior cerebellar peduncle or synapse at CNVIII nuclei
ends at ipsilateral flocconodular lobe
vestibulocerebellar pathway
regulates extensor muscle tone and travels through inferior cerebellar peduncle
forms vestibulospinal tract and signals to motor neurons of spinal cord to maintain posture
fastigial vestibular pathway (vestibulospinal)
regulates extensor muscle tone and travels through inferior cerebellar peduncle
contributes to medial longitudinal fasciculus
transmits info to motor nuclei of CN III, IV, VI to modify and control eye movements
fastigial vestibular pathways
modifies ipsilateral motor activity and travels through ipsilateral superior cerebellar peduncle
(goes through VL of thalamus and crosses over to dentate nucleus)
info relayed to corticospinal tract and modulates motor activity of descending pathways
dentatothalamic pathways
modifies ipsilateral motor activity, travels through ipsilateral superior cerebellar peduncle to contralateral red nucleus
influences rubrospinal tract (acts on proximal flexor muscles of upper limb)
globose-emboliform-rubrate pathway (rubrospinal)
travels through inferior cerebellar peduncle
modulatory info to medial and lateral reticulospinal tract (regulation of muscle tone and posture)
Fastigial reticular pathway (reticulospinal)
Modulates spinal cord motor activity
Controls rhythmic discharges that can manifest as oculopalatal tremor or palatal myoclonus
Guillain-Mollaret triangle (myoclonic triangle)/ (dentato-rubro-olivary pathway)
know
often results in degeneration of the midline portion
of the anterior lobe of the cerebellum
broad-based gait ataxia
chronic alcoholism
Tumor occurs in cerebellar vermis and account for 25% of all childhood intracranial tumors.
HA’s, CN involvement, N/V due to non-communicating hydrocephalus
medulloblastoma
Autosomal recessive condition with an age of onset from 8-16 years
atrophy of spinocerebellar pathways (ataxia)
Patients also have a peripheral neuropathy and posterior column degeneration, which results in a severe loss of vibration and proprioception and further contributes to gait instability and falls
Friedreich’s Ataxia
There is also some degree of corticospinal tract degeneration, and patients typically have bilateral extensor plantar responses or other upper motor neuron findings
Friedreich’s Ataxia
Diagnosis of Friedreich’s Ataxia can be confirmed by testing for trinucleotide repeat ______ on chromosome #9
GAA
