Cerebellum and its connections

1. Cerebellum and its connections
Presenter: Dr Srikanth
Chairperson :Dr Pooja.M

2. Overview
• History
• Development of cerebellum
• Anatomy
External anatomy
Internal anatomy
• Cerebellar connections
• Functions of Cerebellum

3. History- Cerebellum
• Latin word- “little brain”
• Direct translation of the Ancient
Greek paregkephalis
– Used in the works of Aristotle
• The first known writer to describe
the structure

4. History
• Andreas Vesalius and Thomas
Willis:
Earliest scientists to describe
anatomy
• Luigi Rolando and Jean Pierre
Flourens
– Functions
– Consequences of
damage

5. Overview
• History
• Development of cerebellum
• Anatomy
External features
Internal features
• Cerebellar connections
• Functions of Cerebellum

6. Development of cerebellum
Week 3

7. Development of cerebellum
Week 4
Week 5

8. Development of cerebellum

10. Development of cerebellum
• Differentiation of cerebellum starts in 8th
week
• Cerebellar cortex and Purkinje cells- 12th
week
• Dentate nucleus- 15th week

11. Abnormalities of development
1. Dandy-Walker Syndrome
2. Joubert Syndrome
3. Pontocerebellar Hypoplasia
4. Medulloblastoma : arise in the developing
cerebellum from the precursors of the
granule cell.

12. DANDY WALKER SYNDROME

14. Pontocerebellar Hypoplasia
DRAGON FLY APPEARANCE

15. Medulloblastoma

16. Overview
• History
• Development of cerebellum
• Anatomy
External features
Internal features
• Cerebellar connections
• Functions of Cerebellum

17. Anatomy
• External features
1)surfaces and fissures
2)classification systems
3)blood supply
Snells clinical neuroanatomy 7th edition

18. External features
• Situated in the posterior
cranial fossa
• Covered superiorly by the
tentorium cerebelli.
• Largest part of the hindbrain
• Weighs about 150gm
• Lies posterior to the fourth
ventricle, the pons, and the
medulla oblongata
• Ovoid in shape
• Constricted in its median part Snells clinical neuroanatomy 7th
edition

19. External features
Surfaces:
1)Tentorial surface(superior)
2)Suboccipital surface(inferior)
3)Petrosal surface(anterior)
Fissures:
1)Primary fissure
2)Horizontal fissure
3)Uvulonodular fissure

20. Tentorial surface

21. Tentorial surface

22. Tentorial surface

23. Suboccipital surface

24. Suboccipital surface

25. Suboccipital surface

26. Petrosal Surface

27. Petrosal Surface

28. LARSEL Classification
• Larsell subdivided the cerebellum into 10
lobules (I to X)
• Anterior lobe- lobules I-V,
• Posterior lobe- lobules VI-IX and
• The flocculo-nodular lobe- lobule X

29. Lobules

31. Anatomy
Classification systems:
1)Anatomical
2)Phylogenetic
3)Functional
Snells clinical neuroanatomy 7th edition

32. Anatomical classification
Snells clinical neuroanatomy 7th edition

33. Functional classification
Guyton and Hall 13th edition

34. Phylogenetic classification

35. Archicerebellum/vestibulocerebellum
• First to appear
• Aquatic vertebrates
• Flocculonodular lobe
• Maintenance of
equilibrium ,eye
movements
Brazis 7th edition

36. Paleocerebellum/spinocerebellum
• Next to archicerebellum
in evolution
• Terrestrial vertebrates
• Corresponds to vermis
of ant lobe with
pyramis ,uvula and
paraflocculus
• Muscle tone and axial
and limb movements
Brazis7th edition, Sid Gilman

37. Differences of opinion on
Paleocerebellum
Dejong Neurology
Corresponds to anterior lobe
Guyton and Eric Kandell physiology:
Vermian +
paravermian region(intermediate zone)
-

38. Differences of opinion on
Paleocerebellum
• Greys anatomy:

39. Neocerebellum/cerebrocerebellum
• Developmentally last
• Maximum development
in mammals
• Middle portion of
vermis and most of
cerebellar hemispheres
• Smooth performance of
the skilled acts by
coordination of
movements
Brazis 7th edition

40. Blood supply

41. Superior
cerebellar
artery
Anterior
inferior
cerebellar
artery
Posterior
inferior
cerebellar
artery
1. Superior
peduncle
2. Upper
surface
3. Superior
vermis
4. Most of
dentate
nucleus
5. Upper
portion
of MCP
1.Flocculus
2.Anterior
petrosal surface
of cerebellum
3.Lower portion
of MCP
1.Inferior
cerebellar
peduncle
2.Inferior
vermis
3.Inferior
surface of
cerebellar
hemisphere
Blood supply
Paul Brazis Clinical localisation in
neurology 7th edition

42. Vascular territories of cerebellum
Snell neuroanotomy 7th edition

43. Vascular territories

44. AICA infarct

45. PICA infarct

46. Blood supply
PICA infarct SCA infarct
1.More commonly associated with mass
effect(30%) cases
2.Along with gait imbalance vertigo and
headache are common
3.Embolism and thrombosis are equally
common
1.Less common(7%)
2.Vertigo and headache are less common
3.Cardiac embolism and artery to artery
embolism predominant mechanism
Brazis clinical localisation in neurology 7th edition

47. Anatomy
Internal anatomy
1)gross cross sectional anatomy
2)histology
3)internal circuitry

48. Cut section
Snells neuroanatomy 7th edition

49. Snells neuroantomy 7th edition

50. Histology
Snells neuroantomy 7th edition

51. Olivo cerebellar
fibres
FUNCTIONAL
UNIT OF
CEREBELLUM
Neuroscience by Dale purves 6th edition

52. Role of Golgi and Stellate cells
• parallel fibers activate
• clear the activity of the Purkinje cells shortly
after they have been excited
Golgi cells Stellate cells
Inhibit granule cells Inhibit purkinje cells

53. Internal circuitry
Guytons Physiology 12th edition

54. Internal circuitry
Guytons Physiology 12th edition

55. Internal circuitry
• Initial excitatory followed by inhibitory signal
from deep cerebellar nuclei helps
1) increases speed of initiation of
movement(TURN ON)
2) inhibits overshooting of movement later on
called “DAMPING EFFECT”(TURN OFF)
Guytons Physiology 12th edition

56. Motor error detection
• Climbing fibre-purkinje Cell connections are
involved in motor error detection
• Climbing fibres are powerful activators of
Purkinje cells (produce complex spikes at
synapse) and also one climbing fibre has
connection with 3-4 Purkinje cells
• Whenever error is detected climbing fiber
signal cerebellum and hence terminate
movement
Guytons Physiology 12th edition

57. Motor error correction
Spino- Olivary fibres (proprioception)
Inferior olivary nucleus
Climbing fibres
Cerebellum
Cortex/spinal cord via red nucleus or vestibular nucleus(correction of
movement)

58. Motor learning
• Result of plasticity of the synapse between
the parallel fiber and the Purkinje cell
• Long term depression of parallel fibre
synapses that were active when error
happened so that when next time when same
movement is done the “right synapses” are
excited.
Guytons Physiology 12th edition

59. Neurotransmitters in cerebellum
Snells Neuroanatomy 7th edition

60. Cerebellar afferent connections
1. From the Cerebral Cortex
2. From the Spinal Cord
3. From the Vestibular Nerve

61. Afferents from cerebral cortex
Snells Neuroanatomy 7th edition

62. Afferents from spinal cord and
vestibular nerve
Snells Neuroanatomy 7th edition

63. The spinocerebellar pathways
Transmit impulses at velocities up to 120 m/sec
The most rapid conduction in any pathway in the CNS
Important for instantaneous appraisal of the cerebellum of
changes in peripheral muscle actions
Guyton and Hall, 12th edition
Ventral SCT pathway
Tells the cerebellum which motor signals have arrived at the
anterior horns
Efference copy of the anterior horn motor drive
Active only during active movements
Guyton and Hall, 12th edition
Principles of Neural Science, Eric Kandel
Some more facts........

65. Cerebellar Efferents
Snells Neuroanatomy 7th edition

66. Cerebellar Efferents
Rubrospinal Tract
Snells Neuroanatomy 7th edition

67. Cerebellar Efferents
Snells Neuroanatomy 7th edition

68. Cerebellar Efferents
Snells Neuroanatomy 7th edition

69. Reticular formation
vermis
reticulocerebellar
fastigoreticular
Reticulospinal
tracts
Pontine RST
Increase extensor
tone
Medullary RST
Increase flexor muscle tone

71. Peduncles and Connections
Superior cerebellar
peduncle
1)Anterior spinocerebellar
2)Tectocerebellar
1)cerebellorubral
2)Dentatothalamic
3)Dentatoolivary
Middle cerebellar peduncle Pontocerebellar
Inferior cerebellar
peduncle
1. Posterior
spinocerebellar
2. Cuneocerebellar
3. Olivocerebellar
4. Reticulocerebellar
5. Vestibulocerebellar
1. Fastigioovestibular
2. Fastigioreticular
Peduncles Afferents Efferents

72. Recurrent loops
1)cerebellum-cerebral cortex
2)cerebellum-inferior olivary nucleus
3)Golgi cells-granule cells
Eric Kandell physiology

73. Spino-olivary Red nucleus
Inferior olivary nucleus
cortex
Basal ganglia
Reticular
system
All parts of
cerebellum
Climbing
fibers
Cerebellum-olivary loop

75. Cerebellum as a Comparator
Snells Neuroanatomy 7th edition

76. Overview
• History
• Development of cerebellum
• Anatomy
External anatomy
Internal anatomy
• Cerebellar connections
• Functions of Cerebellum

77. Functions of Cerebellum
Can be divided into functions of
1)Vestibulocerebellum
2)Spinocerebellum
3)Cerebrocerebellum
Guytons Physiology 12th edition

78. Cerebellar homunculus
Guytons Physiology 12th edition

79. Vestibulocerebellum
• Consists of flocculonodular
lobe
FUNCTIONS:
1. BALANCE
2. EYE MOVEMENTS
• It causes change in position of
eyes and trunk in response to
head movement
Guytons Physiology 12th
edition

80. Guytons Physiology 12th
edition

81. Connections of the Vestibulocerebellum
Flocculonodular
Lobe
FASTIGIAL
NUCLEUS
VESTIBULAR NUCLEUS
Vestibular
Organ
Lower motor neuron
LMN
Vestibulocerebellum
Vestibulospinal tract
Guytons Physiology 12th
edition

82. Cerebellum and eye movements
control
1)Dorsal Vermis(oculomotor vermis)-
-Lobules VI and VII with underlying
fastigeal nuclei(fastigial occulomotor region-
FOR)
2)Flocculus and paraflocculus
3)Nodulus and ventral Uvula
Brazis localistion in Neurology 7th
edition

83. Amir Khermand etal-frontiers in
Neurology 2011

84. Cerebellum and eye movements
control
Dorsal Vermis(oculomotor vermis)
Function Lesion
1)saccade amplitude and direction saccadic
dysmetria
2)Pursuit initiation
3)horizontal alignment
Brazis localistion in neurology
7th edition

85. Saccades IBN-inhibitory
burst neurons
EBN-Excitatory
burst neurons
NRTP-Nucleus
reticularis tementi
pontis

86. Cerebellum and eye movements
control
Flocculus and paraflocculus
Function: lesion
1)Gaze holding gaze evoked,down beat
and rebound nystagmus
2)Smooth pursuits
3)Match pulse step postsaccaic drift
Brazis localistion in neurology 7th edition

87. Pursuits
DLPN-
Dorsolateral
pontine nuclei
NRTP-Nucleus
reticularis
tementi pontis
MVN-medial
vestibular nuclei
Amir Khermand etal-frontiers in
Neurology 2011

88. Amir Khermand etal-frontiers in
Neurology 2011

89. Cerebellum and eye movements
control
3)Nodulus and ventral Uvula
Function:
Down ward smooth pursuit
Influence low frequency rotational VOR
Lesion:
Periodic alternating nystagmus
Down beat nystagmus
Brazis localistion in neurology 7th edition

90. Spinocerebellum
• Vermis and Intermediate zone of
cerebellar hemispheres(para
vermal regions)
• Controls limb movements
1)comparison of intended movement
and ongoing movement
2)detection of error
3) correction of error by corticospinal
and rubrospinal and reticulospinal
tracts
Guytons Physiology 12th edition

91. Connections of spinocerebellum

92. Balance maintenance
• Brought about by change in muscle tone when
posture changes and both vestibulo and
spinocerebellum is involved
Guytons Physiology 12th edition

93. (posture adjusted)
Cerebellum
Spinocerebellar tracts
Cuneocereballar tracts
Tectocerebellar(visual /auditory)
Vestibulospinal
Reticulospinal
Rubrospinal
Anterior horn
cells
(Change in posture)
Control of posture
Guytons Physiology 12th edition

94. Cerebrocerebellum
• Lateral parts of cerebellar
hemispheres
• Help in
1)Planning of movements in
collaboration with
premotor/somatic sensory
areas and basal ganglia
2)Timing of
movements(smooth
progression of movements) as
in writing,typing,talking
Guytons Physiology 12th edition

95. Connections of the Cerebrocerebellum
CEREBRAL
CORTEX THALAMUS
Pontine
Nucleus
Lower motor
neuron
LMN
DENTATE
NUCLEUS
Lateral
CEREBELLAR
HEMISPHERE
Cerebrocerebellum
Pyramidal
tract
Guytons Physiology 12th edition

96. Cerebellar syndromes
• 1)Rostral vermis syndrome
• 2)Caudal vermis syndrome
• 3)Hemispheric syndrome
• 4)Pan Cerebellar syndrome

97. Cerebellar syndromes
Rostral vermis syndrome:
• lesion involving vermis of anterior lobe
• Seen in Alcoholics
Features:
1. A wide-based stance and titubating gait
2. Ataxia of gait, but proportionally little ataxia
on the heel-to-shin maneuver
3. Normal or only slightly impaired arm
coordination
4. Hypotonia, nystagmus, and dysarthria are
uncommon Brazis localisation in Neurology
7th edition

98. Alcoholic Cerebellar degeneration

99. Cerebellar syndromes
Caudal vermis syndrome
Features:
1. Axial disequilibrium and staggering gait
2. Little or no limb ataxia
3. Sometimes spontaneous nystagmus and
rotated postures of the head
Example: Medulloblastoma
Brazis localisation in Neurology 7th
edition

100. Cerebellar syndromes
Hemispheric syndrome:
Features:
1. Incoordination of ipsilateral appendicular
movements
2. Dysarthria
Examples: Infarcts, neoplasms, and abscesses

101. Cerebellar syndromes
Hemispheric syndrome
Signs:
1)Intention tremor
2)Dysmetria(under or over shooting)
2)Dysdiadochokinesia
3)Impaired Heel Knee test and Finger nose
incordination
4)Hypotonia

102. Cerebellar syndromes
Pancerebellar Syndrome :
Combination of all
Features:
B/l signs of cerebellar dysfunction affecting the
trunk, limbs, and cranial musculature.
Examples:
- Infectious
- Parainfectious processes
- Metabolic/Toxic
- Paraneoplastic cerebellar degeneration
Brazis localisation in Neurology 7th
edition

103. Hypotonia:
Causes:
1)Decreased tonic input of cerebellar nuclei
with loss of cerebellar facilitation of cerebral
cortex
2)Decreased fusiomotor activity at the level of
nuclear bag and chain fibres
Result in pendular knee jerks(also by loss of
checking of reflex response)
Brazis 7th edition/Dejong 7th edition

104. Dysarthria:
Defective articulation and prosody(melody and
continuity)
Result of
1) generalised hypotonia
2) Loss of coordination between muscles of speech
Seen with lesion of left cerebellar hemisphere esp-
superior paravermian
(possibly because of connection with rt cerebral
hemisphere- associated with prosody)
Agramatic speech-Right cerebellar hemispheric
lesion
Brazis localisation in neurology 7th edition

105. Non motor functions of cerebellum
• Cognitive functions(Cerebellar
hemisphere) :
1. Procedural learning
2. Executive functions
3. Language processing
4. Visual and spatial orientation
5. Sensory processing
6. Attention
Mario Manto et al
Cerebellum & Ataxias (2015)

106. Mario Manto et al
Cerebellum & Ataxias (2015)

107. PSYCHIATRIC FEATURES:(VERMAL
LESIONS)
• 75% of pts with degenerative ds of cerebellum
psychiatric manifestations within 10-15 yrs
1. 1/3rd : Major depression
2. 1/3rd Dysthymia, brief recurrent depression.
3. 25% Personality changes

109. Mario Manto et al
Cerebellum & Ataxias (2015)

110. Extramotor Predictive Functions of the
Cerebrocerebellum
Helps to “time” events other than movements of
the body
A person can predict from the changing visual
scene how rapidly he or she is approaching an
object
Guyton and Hall, 12th edition
Word association task- Increased activity in the
right lateral cerebellum
Principles of Neural Science, Eric Kandel
Points to ponder…..

111. The cerebellum weighs only 10% as much as the cerebral cortex,
but its surface area is about 75% of that of the cerebral cortex
Ganong’s Review of Medical Physiology, 24th edition
Each Purkinje neuron receives synaptic input from only a single
climbing fiber
Each climbing fiber contacts 1 to 10 Purkinje cells
Each Purkinje neuron is contacted by axons from 200,000 to 1
million granule cells
Some neurons in the dentate nucleus fire some 100 ms before a
movement begins and even before the discharge of neurons in
either the primary motor cortex or interposed nuclei
Principles of Neural Science, Eric Kandel
Points to ponder…..

112. References
• Snells clinical neuronatomy 7th edition
• Guyton and Hall medical physiology 12th edition
• Paul Brazis localisation in neurology 7th edition
• Neuroscience by Dale purves 6th edition
• Bradleys neurology
• Dejong neurologic examination 7th edition
• Eric Kandel physiology
• Sid Gillman