posterior half of substantia nigra

contains numerous melanin-containing neuron cell bodies using DA as a neurotransmitter

in the midbrain

putamen

GP

IC

body of caudate nucleus

caudate nucleus + putamen + NA

afferent axons fron cerebral cortex and substanatia nigra

efferent axons project to GP

Made of:

STRIOSOMES: AChE-poor patches

MATRIX: AChE-rich 

cholinergic interneurons are present

MEDIUM SPINY NEURONS:dendrites respect patch borders

very little spontaneous firing

neurotransmitter is GABA

mostly GP

efferent axons project to the thalamus through subthalamic fasc.

     ansa lenticularis (more anterior) loops around IC

     lenticular fasc. (more posterior) passes thru IC

     both together: thalamic fasc.

exhibit a high rate of spontaneous firing

neurotransmitter is GABA

tonic inhibition of targets (on the thalamus)

for face and limb movements

activate agonists & inhibit antagonists

corticostriate projections (+)

   (premotor, primary motor, and supplementary motor)

   GLUTAMATE 

   layer V projection fibers

striatopallidal projections (-)

   direct pathway: to internal GP, GABA & substance P

   indirect pathway: to external GP, GABA & enkephalin

pallidothalamic projections (-)

   internal GP to thalamus (VL Nucleus)

   GABA 

thalamocortical projections (+)

   VL nucleus to cerebral cortex

   GLUTAMATE

also nigrostriatal projection

   DA is (+) or (-) depending on the receptor, enhancing it

subthalamic fascthru the IC

pallidosubthalamic (-)

   GABA

   GLUTAMATE

too little DA from the substantia nigra

causes slow, weak movements

Anterior Lobe

Posterior Lobe

Flocculus

nodulus 

tonsil (behind pyramid)

primary fissure

posterolateral fissure

vermis (medial zone) 

   SCA & PICA

hemisphere (lateral zone)

   SCA & AICA

   paravermis (intermediate zone in hemisphere)

paths in & out of the cerebellum, collection of axons

SCP (superior) - axons to red nucleus of midbrain & 

   axons from cerebellar nuc. to VL/VA nuclei of thalamus 

   (decussate at level of inf. colliculus) (efferent)

MCP (middle) - axons from pontine nuclei (afferent)

ICP (inferior)

   restiform body - axons from spinal cord to medulla

   juxtarestiform body- axons to & from vestibular nuclei

inf. hemisphere

MCP

flocculus

dentate nucleus

inf. vermis

ICP

nodulus

tonsil

superior vermis

superior hemisphere

SCP and MCP

cerebellar nuclei

posterior spinocerebellar tract (PSCT)

anterior spinocerebellar tract (ACST)

lateral corticospinal tract (CST)

vestibulospinal tract (VST)

medial reticulospinal tract

lateral reticulospinal tract

MLF

inferior olivery nuclei

olivocerebellar fibers

molecular -- dark layer

   basket cells

   stellate cells

   dendrites of Purkinje cells

   climbing fibers

   paraallel fibers (axons of granule cells)

Purkinje Cell -- black dots

granular

   granule cells

   golgi cells

   mossy fibers

   climbing fibers

   axons of Purkinje cells

subcortical white matter

deep cerebellum

external to cerebellum

orig. in inf. olivary nuc (C/L)

enter cerebellum thru restiform body of ICP

synapse in cerebellar nuc on Purkinje cells

many synaptic contacts on ea. Purkinje from 1 climbing fiber

1 climbing fiber may synapse on several Purkinje cells

complete hemi-section (very rare) could be partial

Motor:

lateral CST:    I/L UMN signs below the lesion

anterior horn: I/L LMN signs at the level of the lesion (LMN signs predominate over UMN signs)

Sensory:

PCMLS:         I/L loss of discriminative touch and proprioception below the lesion

ALS:             C/L loss of pain and temperature below the lesion 

Brown- Sequard  

Syringomyelia

B/L, but not necessarily symmetrical

loss of pain and temperature on the affected dermatomes

Medial medullary syndrome (Dejerine Syndrome)

PCMLS

CST

 if ASA is occluded…B/L, or a branch: C/L above the decussation, I/L below the decussation 

Foville Syndrome

a vasculature syndrome of the pons

paramedian br of basilar A.

Gubler Syndrome

a vasculature syndrome of the pons

circumferential  br of basilar A.