Extrapyramidal tract

Definition of extrapyramidal tract with mentioning the types with details and relation to Parkinson's disease

1. Extrapyramidal Tracts
Name: Ali Al-Nasrullah

2. Learning Objectives
IdentifyingPyramidaltract.
IdentifyingExtrapyramidaltractsorigin,termination
andfunction.
Explainingextrapyramidaldisorders.
ExplainingParkinsondisease.

3. Pyramidal Tract
Itisconsistedof3tracts,Anterior&LateralCorticospinaltractandsomeof
corticobulbartract.
*Whiletravelingformthecerebralcortexthesefibersgivetheapperanceof
apyramidontheupperpartofthemedulla.
Theyterminateintheanteriorgreymatter.
Function:Voluntary,fine&skilledmovementsofthebody.
Otherfibersthanthese3arenamedextrapyrimdal.

4. Extrapyramidal Tracts
Definition :
Thedescendingspinaltractswhichisconcernedwithmotorfunctionsother
thanpyramidaltract.Theyareconsideredasanindirectmotorpathway.

5. Extrapyramidal Tracts
Theyareconsistedofaseriesoftracts:
RubrospinalTract.
ReticulospinalTract,Divididinto2types:
A-pontinereticulospinaltract.(Medial)
B-Medullaryreticulospinaltract.(Lateral)
TectospinalTract.
VestibulospinalTract.

6. Rubrospinal Tract
Originatedfromtherednucleuslocatedinthemesencephalon
Terminateinthelateralcolumnofspinalcord.
Function:Motorfunctionsofskeletalmusclesofthelimbs,
hands,andfeet.

7. Reticulospinal Tract
A-pontinereticulospinaltract.(Medial&Excitatory)
Originatedfrompontinereticularnucleiinponswhichterminate
inthemedialanteriorcolumn.
B-Medullaryreticulospinaltract.(Lateral&Inhibatory)
Originatedfrommedullaandterminateinlateralanterior
column.
Function:ItFacilitatesextensorreflexes&InhibitsFlexor
reflexes.

8. Tectospinal Tract.
Origin:Superiorcolliculusofmidbrain.
TerminateintheAnteriorColumn.
Function:MotorfunctionoftheSkeletalmusclesoftheheadand
eyesinresponsetovisualstimuli.

9. Vestibulospinal Tract
Origin:vestibularnucleusinmedulla.
TerminateintheAnteriorMotorNeuron.
Function:Motorfunctionofmuscleformaintainingbalancein
responsetoheadmovements

10. Extrapyramidal Disorders
TheyarealsonameddisordersoftheBasalGanglia,becausethe
basalgangliawereonceconsideredtoformaseparate
extrapyramidalmotorsystem.
CAUSES OF EXTRAPYRAMIDAL DISORDERS
Drugs,Toxins,hereditary.
Itcanbedividedintotwoclasses:
Hyperkinetic&hypokinetic

11. Extrapyramidal Disorders
Hyperkinetic:
seeninsuchdisordersas
Chorea(dance)
Athetosis(“withoutposition”):
Slow,writhing,continuous,wormlikemovementsofthedistalpartsofthe
extremities,whichshowbizarreposturing.
ballism(jumporthrow),dystonia,tremor,andHuntingtondisease.

12. Extrapyramidal Disorders
Hypokinetic:
seenlargelyinParkinson’sdiseaseandParkinsonplussyndromes.
reducedfacialexpression(mask-like)
reducedblinking
reducedadjustmentsofposturewhenseated.

13. Extrapyramidal Disorders
Parkinsonism
Sixfeatures:
1.RestTremor,2.Rigidity,3.Bradykinesia,4.Flexedposture,5.Lossof
posturalreflexes(fall),6.Freezingphenomenon
Tremor, rigidity, and flexed posture are referred positive phenomena.
Bradykinesia, loss of postural reflexes, and freezing are negative phenomena.

14. Rest Tremor
Presentintheextremities,almostalwaysdistally
Resttremordisappearswithactionbutreemergesasthelimbmaintaina
posture(atrest).
Resttremorisalsocommoninthelips,chin,andtongue
Resttremorofthehandsincreaseswithwalking
Stressworsensthetremor

15. Extrapyramidal Disorders
Parkinson’s disease
Who is this ?
Mohammed Ali Clay
Heavy weight champion boxer

16. Extrapyramidal Disorders
Parkinson’s disease
Who is this ? Michael J. Fox
„Back To The Future“

17. Basal ganglia :
caudate,
putamen&
globuspallidus
arenamed
corpusstriatum
Caudate
&putamenare
named
striatum
globuspallidus&
putamenare
namedlentiform
nuclei
caudate
putamen
globus pallidus

21. Extrapyramidal Disorders
Parkinson’s disease
Itischaracterizedasarestingtremor.
Cause:
Degeneratingsubstantianigraparscompacta(theregionofdopaminergic
neuronsprojectingtothesubstantianigra).
It’sstillnotknownwhatcausesthisdegeneration
(1)rigidity,(2)bradykinesia,(3)tremor,and(4)Lossofposturalreflexes(fall),
Gaitdisorder(shortsteps).
Autonomicfindings:Constipation,posturalhypotension,sweeting.
%20-40Atlatestagesdementiaoccure.
Bythetimesymptomsappear,thesubstantianigraalreadyhaslostabout60%of
dopaminergicneurons.

22. Extrapyramidal Disorders
Parkinson’s disease
Meanageatonsetinbothsexesis55years
(range:20-80).
Over60yearsofageriskofParkinson’sdiseaseis1%
Male/female=3/2.

23. Extrapyramidal Disorders
Parkinson’s disease
Diagnosis
Basedonclinicalfindingsandsigns(Thedoctorsinformation)
CTorMRIbrainscantoexcludeothercauses.PositronEmissionTomography
maydetectlowlevelsofdopamineinthebrain.
ButPETscanningisn'tcommonlyusedtoevaluateParkinson'sbecauseit'svery
expensive,notavailableinmanyhospitals,andonlyusedexperimentally.

24. Extrapyramidal Disorders
Parkinson’s disease
Treatment
Aimedatcontrollingsymptoms.
Itincludespharmacotherapy,physiotherapyandsurgery.
Levodopa(Dopamineprecursor)isthemosteffectivedrug,BUT75%of
patientshaveseriouscomplicationsafter5yearsofLDtherapy.
Dopamineagonists—bromocriptine,pergolide
DeepbrainstimulationisthemaintypeofsurgeryforParkinson’sdisease

26. Extrapyramidal Disorders
Parkinson’s disease
FutureTreatments:
Someresearchersarehopefulthatstemcelltreatmentsorgene
therapywillbehelpfulforpeoplewithParkinson’sdisease.
Currently,researchintostemcelltreatmentsandgenetherapyis
onlyinitsinitialstages.

27. Summary
Pyramidaltractisconsistedof3tracts,Anterior&LateralCorticospinaltract
andsomeofcorticobulbartract.
Extrapyramidaltractsisconcernedwithmotorfunctionsotherthanpyramidal
tract.Theyareconsideredasanindirectmotorpathway.
RubrospinalTract.ReticulospinalTract,Divididinto2types:A-pontine
reticulospinaltract.(Medial)B-Medullaryreticulospinaltract.(Lateral),
TectospinalTract.,VestibulospinalTract.
Extrapyramidaldisorderscanbedividedintotwoclasses:Hyperkinetic&
hypokinetic
HypokineticisseenlargelyinParkinson’sdiseaseandParkinsonplus
syndromes.
Resttremorpresentintheextremities,almostalwaysdistally
Degeneratingsubstantianigraparscompacta(theregionofdopaminergic
neuronsprojectingtothesubstantianigra)It’sstillnotknownhow.

28. Refrences
Neurology and Neurosurgery Illustrated
by Kenneth W. Lindsay, Ian Bone, and Geraint Fuller 5th edition
Guyton And Hall Textbook of Medical Physiology 12th Edition
Disorders of the nervous system
By Alexander G. Reeves, M.D.
Rand S. Swenson, M.D., Ph.D.
Hauser RA et al; Parkinson Disease, Medscape, Jan 2013
http://www.brainandspine.org.uk/parkinsons-disease