Cell Layers
Molecular Layer
 The most superficial layer
 Sparsely cellular
 Synaptic layer
Purkinje’s Layer
 Middle layer
 Discontinuous layer
 Single row of cells which are o Large o Flask-shaped
Granular Layer
 Receive major input into the cerebellum
Components
Stimulatory components
Inhibitory components
Axons (parallel fibers) of Granule cells
Dendrites of Purkinje cells
Purkinje cells
Mossy fiber
Cerebellar Cortical Cell Layers
Climbing fibers
Stellate cells
Basket cells
Characteristics
 Arise from Granule cells at the Granular layer
 The axons bifurcate at this level, giving rise to 2 horizontal fibers
 Generate tens to thousands of synapses with the o Purkinje cell dendrites o Stellate cells o Basket cells o Golgi cells
 Arise from Inferior Olivary Nucleus of the Medulla Oblongata
 Runs parallel to the dendrites of Purkinje cells
 Stimulate Purkinje cells
 Appears as thin black line around the dendrite of Purkinje cell in Renson’s method
 Sparsely scattered
 Small cell with branching of dendrites o Makes it appears like a star
 Unmyelinated fibers runs parallel to the cerebellar folia
 Special species of stellate cells
 Close to the Purkinje cells
 Axons run transversely in the molecular layer
 Arborized around the Purkinje cells
 Inhibit activity of Purkinje cells in coordinating muscular activity
 Arises from the Purkinje cells of Purkinje layer
 Each Purkinje cell gives rise to 2-3 main dendrites directed to the Molecular layer
 Arborization of Purkinje cell dendrites give a distinctive characteristic of fan-shaped fibers
 Purkinje cell dendrites run parallel to climbing fiber
 o o o o
Dendrites



Give rise 2-3 dendrites
Projected to Molecular layer
Arborized into tens to thausands of smaller branching
Build synapses with
Stellate cells
Basket cells
Golgi cells
 Axons of granule cells
 Climbing fibers
 Axons o Projected downward into Granular layer into medullary core o Marks the beginning of cerebellar outflow o Project upon
 Deep cerebellar nuclei
 Extracerebellar targets
 Sends impulses outside the cerebellum
 Inhibitory neurotransmitter always GABA
 Terminations of fibers coming into the cerebellum
Olivocerebellar fiber
Granule cells
Golgi Type II cells
 Fibers that constitute the Climbing fiber at the Molecular layer
 The only fiber that does’nt terminate at the Granular layer
 Sends axons into the Molecular layer
 The axons bifurcate at the level of Molecular layer giving rise to horizontal layers
 Makes synapses with o Purkinje cell dendrites o Stellate cells o Basket cells o Golgi cells
 Located close to the Purkinje cells
 Larger in size compared to Granule cells
 Dendrites arborized at the Molecular layer
 Produce synapses with Granule cells at the Gromeruli of Granule layer
 In each of 10 Purkinje cells there’ll be 1 Golgi Type II cell

Molecular/Plexiform Layer
External/Outer Granular Layer
External Pyramidal Layer
Internal Granular Layer
Internal Pyramidal/Ganglionic Layer
Multiform Layer
 The most superficial layer
 Contains axons and dendrites of cortical neurons which are synapsing with each other
 Closely packed small neuron
 Contained numerous o Smaller Pyramidal/Betz cells
 Shape of a pyramid
 Apex directed outwards (to the
Molecular layer)
 With apical dendrite runs upward
 Periphery gives rise to the horizontally located basal dendrites
 Multipolar in nature
 Chiefly composed of Stellate cells o Stacked closely together
 Medium and large sized Pyramidal/Betz cells
 Intermingled with Granule cells
 Contained o Fusiform cells o Various other kind of cells
 Sparse nuclei cells are neuroglia, occasionally Horizontal cell of Cajal o Granule cells o Cells of Martinotti

Cerebral Cortex
Phylogenetics and Structural Division of Cerebral Cortex
Allocortex/Paleocortex
1.
The oldest part of cerebral primodial cortex
2.
Consists only 1/12 of total cerebrum o
Limbic system o Olfactory cortex
Isocortex/Neocortex
 Youngest part of cerebrum
 Consists of 11/12 of total cerebrum
Homocortex
 The most common
 Makes up most of major part in o Frontal lobe o Parietal lobe o Temporal lobe
Heterocortex
 All 6 layers are developed
 Difference in layer o External
Pyramidal layer o Internal Granular layer o
Internal
Pyramidal/Gangli onic layer
Mortor Cortex/Agranular
Type
 Localized at Area 4-6
(Precentral gyrus)
Sensory Cortex/Granular
Type
 o
Localized at
Area 3,1,2 o o
 Postcentral gyrus
Area 41,42 of Temporal
 lobe
Auditory cortex
Area 17-19 of Occipital lobe
 Visual cortex
1.
Molecular/Plexiform Layer
2.
External/Outer Granular Layer
3.
External Pyramidal Layer
1.
Molecular/Plexiform Layer a.
Layer of Associative function b.
Cajal cells c.
Functional neurons
2.
External/Outer Granular Layer a.
Layer of Receptory function b.
Very numerous neurons c.
Fibers i.
Dendrites
1.
Projected to the molecular layer ii.
Axons
1.
Projected a.
White matter b.
Turn back to Molecular layer d.
Golgi Type II cells
3.
External Pyramidal Layer a.
Layer of Associative function b.
Pyramidal/Betz cells i.
Dendrites run toward Molecular layer ii.
Axons contact the Subcortical nuclei c.
Golgi Type II cells d.
Cell of Martinotti
4.
Internal Granular Layer a.
Layer of Receptory function b.
Golgi Type II cells
5.
Internal Pyramidal/Ganglionic Layer a.
Same to that of External Pyramidal layer
6.
Multiform Layer a.
Irregular fusiform and Angular cells
 Well developed o External Pyramidal layer o Internal Pyramidal/Ganglionic layer
 Poorly developed o Internal Granular layer
 Well developed o Internal Granular layer
 Poorly developed o External Pyramidal layer o Internal Pyramidal/Ganglionic layer