Cerebellum Flashcards
Cerebellum Fuction
-adjusts posture and coordinates mmts
-processes proprioceptive info
-compares intended mmt to actual
-make adjustments
-doesn’t cause muscle weakness, just coordination issues
Cerebellar Peduncles
Superior: mostly efferents; projects to motor nuclei of thalamus, red nucleus
-afferents from spinocerebellar
Middle: afferents; from contra pontine from cortec and sup colliculus, sensory
Inferior: efferents and afferents;
-afferents: vestibular nuc, inf olivary nuc
-efferent: projectt to vestibulospinal and reticulospinal
Cerebellar Cortical Layers
Molecular: interneurons; most superificial
Perkinjie: middle layer; Perkinjie cell bodies; inhibit nuclei; all cerebellar output goes through perkinjie fibers
Granular: interneurons; Deepest layer
-Mossy Fibers: pons and SC to cerebellum
-Climbing fibers: inferior olivary nuc to cerebellum
Deep Cerebellar Nuclei
Dont eat geasy food
-lat to medial
Dentate
Emboliform
Globose
Fastigial
Functional Unit of Cerebellum
Perkinjie (inhibiory) + Deep nuclear cell (excitatory)
Functional Zones
Vestibulocerebellum (Flocculondular lobe)
Spinocerebellum (vermis and inttermediate zone)
Cerebrocerebellum (Lateral hemisphere)
Vestibulocerebellum (Flocculondular lobe)
-lateral vestibular nuc
-balance, eve, proximal trunk mmts
Spinocerebellum (vermis and inttermediate zone)
-only part of cerebellum receives input directly from SC
-Fastigial nuc (vermis): proximal gross mmts of body limbs, eye and prox trunk
-Interposed Nuc (Intermediate zone): distal limb voluntary mmt
Cerebrocerebellum (Lateral hemisphere)
-dentate nuc
-regulates highly skilled mmts and motor planning
Vertebrobasilar A.
-posterior circulation of brain
-midbrain, pons, bedulla
Posterior Inferior Cerebellar A. (Think of location)
-bottom, posterior cerebellum
-tonsils, inferior vermis, inf. peduncle, inf hemisphere
-medulla
Anterior Inferior Cerebellar A.
-front and bottom cerebellum
-middle peduncle, anterior middle cerebellum, flocculus
-pons
Superior Cerebellar A.
-under CN III
-top of cerebellum
-sup and mid peduncles
Posterior Cerebral A.
-posterior cerebrum
-occipital lobe
-Posterior, medial, inferior temporal lobe
-Midbrain
-above CN III
Internal Carotid A.
-anterior circulation of brain
Ophthalmic A.
eyes
Posterior Communicating A.
-connects PCerebralA and ICA
-connects 1 side of ant to post
Anterior Cerebral A.
-medial cerebral hemisphere to parietal lobe
-from ICA
Anterior Communicating A.
-between ant. cerebral A.
Middle Cerebral A.
-lateral cerebral hemisphere
EXCECPT:
-superior and front parietal
-inferior temporal
Vertebral A. Stroke
-prone to shear forces from AA joint from abrupt cervical rotation
-gait issues, ataxia, HA
Basilar A. Stroke
-complete blockage causes death
affects Midbrain (Weber’s Syndrome), pons
-partial: tetraplegia, numbness, ataxia, CN damage, locked in syndrome (only movements)
Anterior Cerebral A. Stroke
-hemiparesis loss to contra side
-personality changes
-lower limb issues
Middle Cerebral A. Stroke
-hemiparesis loss to contra side
-face and upper limb issues
L side: aphasia
R side: spacial relationships, nonverbal communication
Posteror Cerebral A. Stroke
-midbrain issues (thalamic syndrome and Weber’s Syndrome), eye movement issues, cortical blindness (brain cant comprehend vision), ataxia, hemiparesis
Pontine Arteries
-supplies pons
Anterior Inferior Cerebellar A. Stroke
-2nd most common BS stoke
-Lateral Inferior Pontine Syndrome: CN V, VII, VIII, Anteriolateral Spinothalamic issues
Anterior Spinal A. Stroke
-Medial Medullary Syndrome
-CN XII, DCML tract, and Corticospinal
Posterior Inferior Cerebellar A. Stroke
-Most common BS stroke
-Walenberg’s (Lateral Medullary Syndrome): Increased HR, balance issues, facial sensation, secretions, pain and temp issues, swallowing
Inputs of Vestibulocerebellum
-ipsilateral vestibular nuc and visual cortex
-synapses in Flocculonodular lobe
Outputs of Vestibulocerebellum
-project to vestib nuc (posture by vestibulospinal tracts, eye mmts)
Inputs of Spinocerebellum: High Fidelity
-2 neurons ipsi to cerebellum to provide feedback
Posterior Spinocerebellar
-LE
-1st: propprioceptors from LE and trunk to SC FG & Clark’s Nuc
-2nd: Posterior Spinaocerebellar Pathway, ipsi into cerebellar ped. to cortex UNCROSSED
Cuneocerebellar
-UE
-1st: propprioceptors from UE and neck to SC FC and synapse to form Cuneocerebellar pathway in medulla, psi into cerebellar ped. to cortex UNCROSSED
Inputs of Spinocerebellum: Monitoring System
-internal feedback, monitor spinal interneuron
Anterior Spinocerebellar Tract:
-LE
-TL grey matter, divides and most CROSS at midbrain and then CROSSES AGAIN entering sup CP
-each hemisphere gets input from both; automatic coredinated LE movements
Rostrospinocerebellar Tract:
-UE
-grey of cervical SC to T1, to ipsi cerebellum through inf and sup peduncles
Outputs of Spinocerebellum
Vermis: Perkinjie cells project to deep nuclei; medial motor tracts
Intermediate zone: perkinjie cells project to interposed nuclei; lateral motor tracts; distal muscles of limotor mbs and digits
Inputs of Cerebrocerebellar Circuits
-closed cerebro-cerebello-cerebral loop
-motor planning and timing
-changes in dentatte occur before cortex executes movement
-motor and premotor cortices to pontine nuc to lateral cerebellar cortex to dentate nuc to thalamus to cortex
Input: cortex info into pons then CROSS; middle CP into lateral cerebellar cortex
Outputs of Cerebrocerebellar Circuits
Perkinjies of lat cerebellar cortex synapse with dentate; efferents leave sup CP, CROSS, go to thalamus then cortex
Signs of Cerebellar Dysfunction: Everywhere
-coordination but does not affect strength or muscles
-Ataxia
Vermal Ataxia
-trunk
Paravermal Ataxia
-limbs
Signs of Cerebellar Dysfunction: Vestibulocerebellum
Nystagmus: bouncy eye mmtts
-unsteadiness, trunk ataxia, disequilibrium
Signs of Cerebellar Dysfunction: Cerebrocerebellum
Dysarthria: slurred speech
-ataxic finger mmts
Signs of Cerebellar Dysfunction: Spinocerebellum
-Dysarthria: slurred speech
-Scanning/Explosive speech: ataxia of speech; can’t regulate tone or pitch
-Dysdiadochokinesia: rapid mmt issues
-Dysmetria: overshoot or undershoot when moving to a target
-Loss of Check/Rebound: quick removal of resistance creates strong response
-Movement Decomposition: attempting to move 1 joint at a time; compensation
Action Tremor
-shaking limb during mmt
Intention Tremor
-tremor worsens closer to a target
-delays in agonist activity and delay in antagonist brake
Cerebellar Ataxia
-agonsit and antagonist muscles
-EC and EO
-mirror doesnt help
Sensory Ataxia
-DCML
-loss of joint position
-EO helps
-can improve with visual aid
Right Lobe
-language
-executive functions; working mem, muscle control, goal-directed
Left Lobe
-visuospational function
-executive functions; working mem, muscle control, goal-directed
Anterior Lobe
-mediating unconscious proprioception from SC
Posterior Lobe
-initiation, planning and coordination of mmt
-scope of mmt
-GABA
Primary Fissure
-divides ant. and post lobes
Vermis
-midline of cerebellum
-coordinates mmt of central body, posture
-spinocerebellar
Paravermal Area
-mmt of distal limbs
-skilled voluntary mmt
-spinocerebellar
-lateral motor tracts
Dentate Nucleus
-regulates fine control of mmts, cognition, language
-motor planning
Globose Nucleus
-connected to vestib, balance
Emboliform Nucleus
-regulates precision of limb mmts
Interposed Nucleus
Globose+Emboliform= interposed
-eyeblinks and reflexes; agonist-antagoinst pairs
Fastigial Nucleus
-maintain balance, afferent from vermis, interprets body motion
