Lecture 11 - Cerebellum

Question 1

Cerebellum

Answer 1

• coordinates volitional movement by comparing the motor plan with movements as they occur –> feedback to cerebrum and brainstem for correction
• tightly connected to vestibular nuclei
• also does other things

Question 2

Lesions of cerebellum or connections

Answer 2

-lateral: IPSI limb ataxia
-medial: gait ataxia
-lesion more medial than lateral:
vertigo (feeling/hallucination of movement)
Nystagmus (involuntary movement pattern of eye)
Dysarthria (abnormal speech, slurred)

Question 3

Structures

Answer 3

Vertical
-Vermis 
     >Anterior lobe of cerebellum
     >midline
Medial hemisphere (paravermis)
lateral hemisphere

Horizontal

• Primary fissure separates Ant and Post lobes
• Horizontal fissure separates (bisect)
• flocculonodular lobe (superior surface)

Cerebellar peduncles (inf, mid, sup)

Deep nuclei

• Dentate
• interposed (emboliform, globose)
• fastigial

medial = trunk/axial
lateral = limbs

Question 4

Blood supply

Answer 4

PICA (posterior lobe)
AICA (middle
SCA (anterior)

Question 5

Wiring in general

Answer 5

1. input to purkinje cells in cortex
   
   • climbing fibers from CONTRA inf. olive
   • mossy fibers from several sources to interneurons
2. integration in deep nucleus
3. output from deep nuclei through peduncles to various locations

Question 6

Inputs

Answer 6

corticopontine and pontocerebellar tracts

• motor plan from motor cortex (comes down corticopontine)
• at pons, synapse on 2nd neuron –> CONTRA
• other info from other cortical areas

spinocerebellar tracts and brainstem nuclei

• unconscious position sense
• vestibular sense
• IPSI

Question 7

Outputs

Answer 7

superior cerebellar peduncles

• ventral anterior and ventral lateral nuclei of thalamus
• red nucleus

multiple brainstem nuclei
-direct to vestibular nuclei

Cortex –> deep –> superior cerebellar peduncle –> thalamus/red nuclei

Question 8

Cerebellar symptoms/signs

Answer 8

Ataxia: incoordination
-limb: finger-to-nose and heel-to-shin testing
dysmetria: missing target
intention tremor: kinetic, on approaching a target
dysdiadochokinesia: abnormal rapid alternating move
-gait: wide-based, unsteady
-trunk: unable to sit unassisted

Dysarthria: abnormal enunciation
Vertigo, nystagmus, nausea

Question 9

Lateral cerebellar syndrome

Answer 9

dysfunction of lateral cerebellum or connections cause:

• ataxia of IPSI limbs (double cross)
• dysarthria
• vertigo, nystagmus, nausea

Question 10

Medial cerebellar syndrome

Answer 10

• ataxia of gait and trunk
• dysarthria
• vertigo, nystagmus, nausea

Question 11

Cerebellar role in other stuff

Answer 11

• role in motor planning (lateral hemisphere
• correction (medial hemisphere)
• motor learning (connection to inf. olive)
• aspects of cognition