Motor System

1. MOTOR
SYSTEM
DR SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM

2. DEPT. OF PHYSIOLOGY, GMCM 3
Specific Learning Objectives
•Introduction
•Organization of Motor System
•Muscle and its connections
•Structure of Muscle Spindle
•Effect of various conditions on mucle spindle discharge
DEPT. OF PHYSIOLOGY, GMCM

3. Movementsarethemajorwayinwhichhumans
interactwiththeworld.
ˈ
DEPT. OF PHYSIOLOGY, GMCM 4

4. •Contractionofskeletalmusclefibersareresponsible
forthemovementofthebody.
•Motorfunctionofnervoussystemisthecontrolof
skeletalmuscleactivity.
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5. MotorSystemplaysaroleininducingvoluntaryactivity,to
adjustbodyposture,andtomakemovementssmooth
andprecise.
DEPT. OF PHYSIOLOGY, GMCM 6

6. DEPT. OF PHYSIOLOGY, GMCM 7
Specific Learning Objectives
•Introduction
•Organization of Motor System
•Muscle and its connections
•Structure of Muscle Spindle
•Effect of various conditions on mucle spindle discharge
DEPT. OF PHYSIOLOGY, GMCM

7. Organization of Motor System
1.Muscle and its connections
2.Segmental circuit in spinal cord
3.Brainstem controlling centres
4.Basal ganglia, cerebellum
5.Thalamus
6.Cerebral cortex
DEPT. OF PHYSIOLOGY, GMCM 8

8. STRETCH REFLEX
DEPT. OF PHYSIOLOGY, GMCM 9

9. Stretch Reflex
•Whenaskeletalmusclewithanintactnervesupplyis
stretched,itcontracts.
•Thisresponseiscalledthestretchreflex.
•Senseorgan–musclespindle
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10. Muscle spindle
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11. 1.Stimulus-stretchof the muscle
2.Sense organ / receptor -muscle spindle (intrafusal)
3.Afferent nerve –group Iafibre
4.Centre–spinal cord (alpha motor neuron)
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12. 5.Efferent nerve –axons of alpha motor neuron
6.Effector organ–extrafusalmuscle fibres
7.Effect-contractionof same muscle
DEPT. OF PHYSIOLOGY, GMCM 13

13. DEPT. OF PHYSIOLOGY, GMCM 14
Specific Learning Objectives
•Introduction
•Organization of Motor System
•Muscle and its connections
•Structure of Muscle Spindle
•Effect of various conditions on mucle spindle discharge
DEPT. OF PHYSIOLOGY, GMCM

14. 1. Muscle and its connections
DEPT. OF PHYSIOLOGY, GMCM 15

15. Muscle has two types of fibers
a. Extrafusal fibers
•Regular striated contractile units of muscle
•Motor Function
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16. DEPT. OF PHYSIOLOGY, GMCM 17

17. b. Intrafusal fibers / Muscle spindle
•Spindleshaped.
•Less distinct striations.
•Do not contribute to overall contractile force, serves
a pure sensory function.
DEPT. OF PHYSIOLOGY, GMCM 18

18. DEPT. OF PHYSIOLOGY, GMCM 19
Specific Learning Objectives
•Introduction
•Organization of Motor System
•Muscle and its connections
•Structure of Muscle Spindle
•Effect of various conditions on mucle spindle discharge
DEPT. OF PHYSIOLOGY, GMCM

19. DEPT. OF PHYSIOLOGY, GMCM 20

20. 1.Eachspindleconsistsupto10intrafusalmuscle
fibres(3-12fibres).
2.Enclosedinaconnectivetissuecapsule,attached
toglycocalyxofsurroundinglargeextrafusalskeletal
musclefibres.
Muscle Spindle
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22. 3.Has contractile polar ends and non-contractile centre
(receptor portion).
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23. 4.Fiberslieparalleltoextrafusalfibers.
Hence,transmitsinformationaboutmusclelengthor
rateofchangeoflength.
5.Sincechangesinmusclelengthareassociatedwith
changesinjointangle,musclespindleprovides
informationaboutposition(proprioception).
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24. 6.Each muscle spindle has 3 elements
a.Intrafusal Fibers
b.Afferent Neurons
c.Efferent Neurons
DEPT. OF PHYSIOLOGY, GMCM 25

25. a. Intrafusal Fibers
2 types of intrafusal fibers
i.Nuclear bag fibers
•Contains many nuclei in a dilated central area
•1-3 in each spindle
•2 subtypes: Dynamicand Static nuclear bag fibers
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28. ii.Nuclear chain fibers
•Nuclei aligned in a chain throughout the receptor area
•Lacks a definite bag
•Thinner and shorter fibers
•3-9 in each spindle
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29. DEPT. OF PHYSIOLOGY, GMCM 30

30. DEPT. OF PHYSIOLOGY, GMCM 31

31. b. Afferent Neurons
•Group Iaand II fibers
•Two types of endings
•Primary/ Annulospiralendings
•Secondary/ Flower Spray endings
DEPT. OF PHYSIOLOGY, GMCM 32

32. i.Primary(annulospiral)endings
1.TerminationsofrapidlyconductinggroupIa
afferentfibers
2.Wrapsaroundcenterofbothdynamicandstatic
nuclearbagfibersaswellasnuclearchainfibers
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33. DEPT. OF PHYSIOLOGY, GMCM 34

34. 3.Respondto
•velocityofchangesinlength→dynamicresponse
•respondtosustainedstretch→staticresponse
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35. DEPT. OF PHYSIOLOGY, GMCM 36

36. ii.Secondary (flower-spray) endings
1.Termination of group II afferent fibers
2.Innervates static nuclear bag fibers as well as nuclear
chain fibers
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37. DEPT. OF PHYSIOLOGY, GMCM 38

38. 3.Respond to sustained stretch → static response
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39. DEPT. OF PHYSIOLOGY, GMCM 40

40. Response to stretch –2 types
1. Static response
•Impulses transmitted from both 1ºand 2ºendings
•Increases directly in proportion to degree of stretching
•Discharge occurs throughout the period of stretching
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41. •Respond to length of receptor.
•Responsible for muscle tone.
DEPT. OF PHYSIOLOGY, GMCM 42

42. 2. Dynamic response
•Impulsestransmittedfrom1ºendingsinnuclearbag
region.
•Dischargerapidlywhenmuscleisstretched.
•Respondtorateofchangeofreceptorlengthduring
stretch.
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43. •Provideinformationaboutthespeedofmovement.
•Allowforquickcorrectivemovementsthatoppose
suddenchangesinmusclelength.
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44. c. Efferent Neurons
•γ motor neurons
•Supply the contractile ends of muscle spindle
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45. Histologically,
•Plate endings → motor end plates in nuclear bag fibers
•Trail endings → motor end plates in nuclear chain fibers
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46. DEPT. OF PHYSIOLOGY, GMCM 47

47. 2 types of γ efferents:
i.Dynamic γ efferents(gamma-d)
•Stimulates dynamic nuclear bag fibers
•Increases sensitivity of Iaafferents → dynamic response
of Iafiber is markedly enhanced
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48. ii.Static γ efferents(gamma-s)
•Stimulatesstaticnuclearbagfibersandnuclear
chainfibers
•IncreasestonicactivityinIaandIIfibers
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49. DEPT. OF PHYSIOLOGY, GMCM 50

50. DEPT. OF PHYSIOLOGY, GMCM 51

51. DEPT. OF PHYSIOLOGY, GMCM 52

52. DEPT. OF PHYSIOLOGY, GMCM 53
Specific Learning Objectives
•Introduction
•Organization of Motor System
•Muscle and its connections
•Structure of Muscle Spindle
•Effect of various conditions on mucle spindle discharge
DEPT. OF PHYSIOLOGY, GMCM

53. 1.Stretchofmuscle
Stretchofmuscle→stretchofmusclespindle→
sensoryendingsgetdistorted→increasedsensory
outputofmusclespindle(Loadingofthemuscle
spindle)→POSITIVEsignal

54. DEPT. OF PHYSIOLOGY, GMCM 55

55. Action potentials are generated at a frequency proportional
to degree of stretching.
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56. 2.Whenmusclecontracts→spindleafferentsstop
firing(Unloadingofthemusclespindle)→
NEGATIVEsignal.
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57. DEPT. OF PHYSIOLOGY, GMCM 58

58. 3.Stimulation of γMotor Neuron
StimulationofγMN→contractileendsofmuscle
spindleshorten→stretchesnuclearbagregion→
increasedimpulsesinsensoryfibers→increases
sensitivityofmusclespindletostretch.
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59. DEPT. OF PHYSIOLOGY, GMCM 60

60. DEPT. OF PHYSIOLOGY, GMCM 61
What are the different ways through which
a muscle can be contracted?
Q

61. DEPT. OF PHYSIOLOGY, GMCM 62
1.Stretch of the muscle –Stretch Reflex
2.Descending Motor Pathways -Corticospinal Tract
3.Gamma Efferent to Muscle Spindle

62. DEPT. OF PHYSIOLOGY, GMCM 63

63. DEPT. OF PHYSIOLOGY, GMCM 64
Specific Learning Objectives
•Introduction
•Organization of Motor System
•Muscle and its connections
•Structure of Muscle Spindle
•Effect of various conditions on mucle spindle discharge
DEPT. OF PHYSIOLOGY, GMCM

64. NEXT CLASS!
[email protected]
DEPT. OF PHYSIOLOGY, GMCM 65

65. MOTOR
SYSTEM 2
DR SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM

66. DEPT. OF PHYSIOLOGY, GMCM 3
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

67. α-γlinkage (α-γcoactivation)
Increased γefferent discharge along with increased
discharge of α motor neuron.
DEPT. OF PHYSIOLOGY, GMCM 4

68. •DescendingpathwayssendsignalstobothαMNas
wellastoγMN.
•αMNandγMNarestimulatedsimultaneously.
•Becauseofthislinkage,intrafusalandextrafusal
fibrescontracttogether(spindleshortenswiththe
muscle)
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69. DEPT. OF PHYSIOLOGY, GMCM 6

70. Two effects
•Keepsthelengthofthereceptorportionofmuscle
spindlefromchangingduringcourseofwholemuscle
contraction.
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1

71. 2
•Spindle remain capable of responding to stretch and
reflexlyadjust motor neuron discharge.
•So, helps to maintain proper damping function of the
muscle spindle, regardless of any change in muscle length.
DEPT. OF PHYSIOLOGY, GMCM 8

72. DEPT. OF PHYSIOLOGY, GMCM 9
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

73. Higher Control of Stretch Reflex
1.Facilitates stretch reflex by increasing γefferent
discharge
i.Facilitatory reticular formation in the brain stem
ii.Vestibular nucleus
DEPT. OF PHYSIOLOGY, GMCM 10

74. 2.Inhibit stretch reflex by decreasing γefferent discharge
i.Cerebral cortex
ii.Cerebellum, basal ganglia
iii.Inhibitory reticular formation
DEPT. OF PHYSIOLOGY, GMCM 11

75. DEPT. OF PHYSIOLOGY, GMCM 12
1-Cortex, 2-Basal Ganglia, 3-Cerebellum, 4-Medullary Reticular
Formation, 5-Pontine Reticular Formation, 6-Vestibular Nucleus

76. Factors influencing γ MN discharge
1.Anxiety
•Increased γMN →
anxious people
2.Unexpected movements
• →
DEPT. OF PHYSIOLOGY, GMCM 13

77. 3.Stimulation of skin by noxious agents
•Increased γMNactivity to ipsilateral flexor muscle spindles
while decreasing that to extensors
DEPT. OF PHYSIOLOGY, GMCM 14

78. 4. Jendrassik’sManeuver
Donebyaskingthesubjectto
makeastrongvoluntarymuscle
contractionandsimultaneously
elicitingthedeeptendonreflex.

79. •Eg.Pullhandsapartwhentheflexedfingersarehooked
together.
•Reinforcementoftendonjerksmaybeduetoincreased
γMNdischargeinitiatedbyafferentimpulsesfrom
hands
•Thusincreasesthesensitivityofmusclespindleto
stretch.
DEPT. OF PHYSIOLOGY, GMCM 16

80. DEPT. OF PHYSIOLOGY, GMCM 17
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

81. DEPT. OF PHYSIOLOGY, GMCM 18
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

82. Functions of Muscle Spindle
1.Acts as a feedback mechanism to maintain muscle length
2.Damping function of dynamic and static stretch reflex
3.Maintenance of muscle tone
4.Maintenance of posture
DEPT. OF PHYSIOLOGY, GMCM 19

83. 1. Feedback mechanism to maintain muscle length
•Stimulated by stretching of muscles
•Provides a feedback mechanism
•Operates to maintain muscle length

84. When muscle is stretched
↓
Increasedspindle discharge
↓
Afferents pass through type Iafibers
↓
Enter spinal cord through dorsal root
↓
Synapses with anterior motor neurons
supplying same muscle
DEPT. OF PHYSIOLOGY, GMCM 21

85. ↓
Reflex shortening of muscle by contraction
of extrafusal fibers
↓
Decreased stimulation of spindle
Muscle relaxation
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86. Two type of responses
1.Dynamic response / phasic response
2.Static response / tonic response

87. 2.Dampingfunctionofdynamicandstaticstretch
reflexes
•Signalsfromspinalcordareoftentransmittedtoamuscle
inanunsmoothform.
•Ifthemusclespindleisnotfunctioningproperlymuscle
contractionswillbejerky.

88. Curve A → normal muscle
Curve B → muscle whose muscle spindles were denervated by section of the posterior roots of the cord 82 days previously

89. DEPT. OF PHYSIOLOGY, GMCM 26
“Signal averaging” .

90. •Markeddynamicresponsehelpstodampenoscillations
causedbyconductiondelaysinfeedbackloopregulating
musclelength.
•Normallyasmalloscillationoccurinthisfeedbackloop-
Physiologicaltremor.
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91. Physiological Tremor
•Normal phenomenon
•Low amplitude, Frequency-10 Hz
•Barely visible to the naked eye
•Become exaggerated when we are anxious or tired or
because of drug toxicity

92. 3. Maintenance of muscle tone
•Toneistheresistanceofferedbyamuscletopassive
stretch.
•Itisastateofpartialcontractionfoundinmusclesat
rest.

93. •Staticresponseofmusclespindlesareresponsiblefor
tone.
•Helpstomaintainposture.
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94. Normaltoneisilldefinedareasomewherebetween
flaccidityandspasticity.
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95. Lowfrequencyasynchronousdischargeofgammamotor
neuroncausesslightcontractionofmuscleunderresting
state.
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96. Hypotonicoccurs when rate of γ motor neuron discharge
is lowand hypertonic when it is high.
DEPT. OF PHYSIOLOGY, GMCM 33

97. 4. Maintenance of posture
Musclespindlestabilizesbodypositionduringtense
motoraction.

98. •Spindlesofmusclesonbothsidesofeachjointare
activatedatthesametime→reflexcontractionofthe
musclesoccur.
•Thisstabilizesthemajorjoints.
•Aidstremendouslyinperformingtheadditionalfine
voluntarymovementsoffingersorotherbodyparts.
DEPT. OF PHYSIOLOGY, GMCM 35

99. DEPT. OF PHYSIOLOGY, GMCM 36
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

100. DEPT. OF PHYSIOLOGY, GMCM 37
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

101. DEPT. OF PHYSIOLOGY, GMCM 38
2. Segmental Circuit in Spinal Cord

102. A.Anterior Motor Neurons
Alpha motor neuron
Gamma motor neuron
B.Interneurons
C.Renshaw Cells

103. A. Anterior Motor Neurons
•Locatedineachsegmentoftheanteriorhornsofspinal
cordgraymatter.
•Giverisetonervefibersthatleavethecordbywayof
anteriorrootsanddirectlyinnervatetheskeletalmuscle
fibers.

104. 2 types
•Alphamotor neurons and
•Gammamotor neurons
DEPT. OF PHYSIOLOGY, GMCM 41

105. Motor root or
Anterior root or
Ventral root

108. Alpha motor neurons
Axons : Aαfibres
14-15 µm in diameter
Innervate the large skeletal
muscle fibers
Gamma motor neuron
Axons : Aγfibres
5 µm in diameter
Supply intrafusal muscle fibres
Alpha v/s Gamma

109. Functions of inputs converging on Alpha motor
neuron
1.Bring about voluntary activity
2.Adjust body posture to provide stable background for
movement
3.Coordinatevarious movements to make movements
smooth and precise

110. Levels of inputs to the Alpha motor neuron
•From samespinal segment
•From suprasegmental levels in the spinal cord
•From brain stem
•From cerebral cortex, basal gangliaand cerebellum

111. B. Interneurons
•Present in all areas of the cord gray matter—in the dorsal
horns, the anterior horns, and the intermediate areas
•30 times as numerous as the anterior motor neurons

113. DEPT. OF PHYSIOLOGY, GMCM 51
Interconnectionsamonginterneuronsandanteriormotor
neuronsareresponsibleformostoftheintegrative
functionsofspinalcord.

114. C. Renshaw cells
•Inhibitory cells
•Transmit inhibitory signals to surrounding motor neurons
•Stimulation of each motor neuron tends to inhibit adjacent
→ lateral inhibition
•Focus or sharpen signals
DEPT. OF PHYSIOLOGY, GMCM 52

115. DEPT. OF PHYSIOLOGY, GMCM 53
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

116. DEPT. OF PHYSIOLOGY, GMCM 54
Specific Learning Objectives
•α-γ linkage (α-γ coactivation)
•Higher Control of Stretch Reflex
•Functions of Muscle Spindle
•Segmental Circuit in Spinal Cord
•Other areas in motor system hierarchy
DEPT. OF PHYSIOLOGY, GMCM

117. 3. Motor Cortex
•Corticospinal tract / pyramidal tract
•Corticobulbar projections→
projections arise
•From sensory cortex to motor cortex -Sensory motor
coordination
DEPT. OF PHYSIOLOGY, GMCM 55

118. 4. Brainstem controlling centers
• →
motor nuclei to αMN
•Reticulospinal tract
•Vestibulospinal tract
•Mainly concerned with postural movements
DEPT. OF PHYSIOLOGY, GMCM 56

119. 5. Basal ganglia
•Subcortical structure
•No direct sensory input from spinal cord
•Project to motor cortex via thalamus
•Involved in initiation, smoothening and coordination of
movements.
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120. 6. Cerebellum
•Receives inputs from all sensory modalities
•Project to brainstem motor nuclei and motor cortex
•Control almost all aspects of movement -planning,
programming, initiation, termination and coordination
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121. 7. Thalamus
•Major sensory relay station
•Receives inputs from cerebellum and basal ganglia
•Plays an important role in sensory motor coordination.
DEPT. OF PHYSIOLOGY, GMCM 59

122. NEXT CLASS!
[email protected]
DEPT. OF PHYSIOLOGY, GMCM 60

123. MOTOR
SYSTEM 3
DR SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM

124. DEPT. OF PHYSIOLOGY, GMCM 3
INPUT OUTPUT

125. DEPT. OF PHYSIOLOGY, GMCM 4
MOTOR OUTPUT
VOLUNTARY MOVEMENTS
REFLEXES
RHYTHMIC MOVEMENTS

126. DEPT. OF PHYSIOLOGY, GMCM 5
Specific Learning Objectives
•Voluntary Movements
•Cortical Motor Areas
•Descending Tracts
•Pyramidal Tract
DEPT. OF PHYSIOLOGY, GMCM

127. VOLUNTARY MOVEMENTS
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128. DEPT. OF PHYSIOLOGY, GMCM 7

129. •Commands forvoluntarymovementsoriginatein
corticalassociationareas.
•Planningandorganizationofmovements→bycortex,
basalgangliaandlateralportionofcerebellum
DEPT. OF PHYSIOLOGY, GMCM 8

130. •Planisprojectedtothemotorandpremotorcortex.
•Commandsaresenttomuscle→viacorticospinaland
corticobulbartracts.
•Feedbackinformationthatadjustsandsmoothens
movementrelayedtomotorcortexandspinocerebellum.
DEPT. OF PHYSIOLOGY, GMCM 9

131. DEPT. OF PHYSIOLOGY, GMCM 10
Specific Learning Objectives
•Voluntary Movements
•Cortical Motor Areas
•Descending Tracts
•Pyramidal Tract
DEPT. OF PHYSIOLOGY, GMCM

132. Cortical Motor Areas
•Control voluntary movement
•Comprises of
1.Primary Motor Cortex
2.Premotor Area
3.Supplementary Motor Area
4.Posterior Parietal Cortex
5.Primary Somatosensory Area
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133. Primary Motor Cortex
•M1, Brodmann area 4
•Located in precentral gyrus of frontal lobe.
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135. DEPT. OF PHYSIOLOGY, GMCM 14

136. 1. Primary Motor Cortex
•M1, Brodmann area 4
•Located in precentral gyrus of frontal lobe.
•Begins laterally in the sylvian fissure, spreads superiorly
to the uppermost portion of the brain.
•Then dips deep into the longitudinal fissure.
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137. •Concernedwithexecutionofmovements.
•Generatessignalsthatcontroltheexecutionof
discrete,individualmovementsratherthanone
specificmuscle
•Topographical Representation –Motor Homunculus
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138. Motor Homunculus
•Figurativerepresentationofbodymapencodedin
primarymotorcortex.
•MappedbyPenfieldandRasmussen.
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142. •Each sideof the body is represented on the opposite
side in the brain.
•Inverted map→ feet at the top and face at the bottom
•Facial area is represented bilaterally.
•Area involved in speech and hand movements → large
representation in the cortex.
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143. •Axialmusculatureandproximalportionsoflimb
representedalongtheanterioredgeofprecentralgyrus.
•Distalpartoflimbalongtheposterioredge.
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145. Corticalrepresentationofeachbodypartisproportional
insizetotheskillwithwhichthepartisusedinfine
voluntarymovement.
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146. •Motorsystem"learnsbydoing"andperformance
improveswithrepetition→corticalplasticity.
•Mapsofmotorcortexarethereforenotimmutable.
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147. 2. Premotor Area
•Brodmann’sarea6
•Liesimmediatelyanteriortoprimarymotorcortex–
extendinginferiorlytoSylvianfissureandsuperiorlyto
longitudinalfissure
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148. DEPT. OF PHYSIOLOGY, GMCM 27
Containsasomatotopicmapthatisroughlysameasthat
ofprimarymotorcortex

149. •Complex“patterns”ofmovement.
•Concernedwithsettingpostureatthestartofaplanned
movementandgettingtheindividualtomove.
•Mostinvolvedincontrolofproximallimbmuscles
neededtoorientthebodyformovement.
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150. Premotor area sends signals
1.Eitherdirectlytoprimarymotorcortextoexcite
specificmuscles
2.Orbywayofbasalgangliaandthalamusbackto
primarymotorcortex
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151. Mirror Neurons?
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152. •Specialclassofneurons-mirrorneuronspresent.
•Transformsensoryrepresentationsofactsthatareheard
orseenintomotorrepresentationsoftheseacts.
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153. •Specialclassofneurons-mirrorneuronspresent.
•Transformsensoryrepresentationsofactsthatareheard
orseenintomotorrepresentationsoftheseacts.
•Importantforunderstandingtheactionsofotherpeople
andforlearningnewskillsbyimitation.
DEPT. OF PHYSIOLOGY, GMCM 32

154. Special areas in Premotor cortex
1.Broca’s area (Motor Speech Area) –related to speech
2.Voluntary eye movement field
1.For moving eyes toward different objects
2.Also controls eyelid movements such as blinking

155. 3.Headrotationarea
•Directstheheadtowarddifferentobjects
•Closelyassociatedwiththeeyemovementfield
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156. 4.Areaforhandskills
•Liesimmediatelyanteriortotheprimarymotor
cortexforthehandsandfingers
•Lesionscausehandmovementsbecomeun-
coordinatedandnon-purposeful-Motorapraxia
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157. 3. Supplementary motor area
•Situatedonandabovethesuperiorbankofcingulate
sulcus.
•Thisareaprojecttomotorcortex.

158. •Involvedinprogrammingmotorsequences–when
movementsperformedarecomplexandneedplanning.
•Lesionsproduceinabilitytoperformcomplexaction
DEPT. OF PHYSIOLOGY, GMCM 37

159. 4. Posterior Parietal cortex
•Two areas: area 5 and area 7
•Provide fibers to corticospinal and corticobulbar tracts
•Project to premotor cortex

160. •Neuronsinarea5areconcernedwithaimingthe
handstowardsanobjectandmanipulatingit.
•Neuronsinarea7areconcernedwithhandeye
coordination.
DEPT. OF PHYSIOLOGY, GMCM 39

161. 5. Primary somatosensory cortex
•Area 3, 1, 2
•Projects to premotor cortex.
•Lesion of somatosensory area affects learned sequence
of movements eg.Eating with knife and fork.
DEPT. OF PHYSIOLOGY, GMCM 40

162. DEPT. OF PHYSIOLOGY, GMCM 41
Specific Learning Objectives
•Voluntary Movements
•Cortical Motor Areas
•Descending Tracts
•Pyramidal Tract
DEPT. OF PHYSIOLOGY, GMCM

163. Descending tracts or Motor pathways
1.Pyramidal tractorCorticospinal tractand
Corticobulbar orCorticonucleartract
2.Extra pyramidal pathways
•Reticulospinal, Vestibulospinal, Rubrospinal,
Tectospinal

164. DEPT. OF PHYSIOLOGY, GMCM 43
Specific Learning Objectives
•Voluntary Movements
•Cortical Motor Areas
•Descending Tracts
•Pyramidal Tract
DEPT. OF PHYSIOLOGY, GMCM

165. DEPT. OF PHYSIOLOGY, GMCM 44
Specific Learning Objectives
•Voluntary Movements
•Cortical Motor Areas
•Descending Tracts
•Pyramidal Tract
DEPT. OF PHYSIOLOGY, GMCM

166. Corticospinal tract or Pyramidal pathway
•Primary pathway for initiation of skilled voluntary
movements.
•Longest tract
•Becomes myelinatedin the first 2 yearsof life.

167. •Corticospinal tract + corticobulbar tract
•1 million fibers in each corticospinal tract
DEPT. OF PHYSIOLOGY, GMCM 46

168. A. Origin
1.30%from Primary motor cortex
2.30%from Premotor cortex and Supplementary motor area
3.40%from Somatosensoryarea posterior to central sulcus

169. DEPT. OF PHYSIOLOGY, GMCM 48

170. Cells of origin
•Giant pyramidal cells of Betz → 3%
•Small pyramidal cells → 97%
DEPT. OF PHYSIOLOGY, GMCM 49

171. Betz cells
•Betz in 1874 described the giant pyramidal cells in 5
th
layer of primary motor cortex.
•Only 3% of CST fibers arise from Betz cells -large cell,
velocity-70m/sec.

173. B. Course
Cerebral cortex-various areas
↓
Corona radiata
↓
Internal capsule –genu and anterior 2/3
rd
of
posterior limb (head region anteriorly, feet posteriorly)

174. DEPT. OF PHYSIOLOGY, GMCM 53

176. B. Course
Cerebral cortex-various areas
↓
Corona radiata
↓
Internal capsule –genu and anterior 2/3
rd
of
posterior limb (head region anteriorly, feet posteriorly)
↓
Midbrain–middle 3/5
th
of crus cerebri
(head medially, feet laterally)

177. DEPT. OF PHYSIOLOGY, GMCM 56

178. ↓
Pons(broken up to discrete bundles by pontine nuclei)
At the lower border collected into a compact bundle
DEPT. OF PHYSIOLOGY, GMCM 57

179. DEPT. OF PHYSIOLOGY, GMCM 58

180. ↓
Pons(broken up to discrete bundles by pontine nuclei)
At the lower border collected into a compact bundle
↓
Medulla –seen as Pyramid
DEPT. OF PHYSIOLOGY, GMCM 59

182. Atthelowerborderofmedulla,
•80%crosstooppositeside–crossedPyramidaltractor
LateralCorticospinaltract
•20%uncrossed fibers –Anterior or Ventral Cortico-
spinal tract
DEPT. OF PHYSIOLOGY, GMCM 61

183. DEPT. OF PHYSIOLOGY, GMCM 62

184. DEPT. OF PHYSIOLOGY, GMCM 63

185. DEPT. OF PHYSIOLOGY, GMCM 64

186. DEPT. OF PHYSIOLOGY, GMCM 65

187. DEPT. OF PHYSIOLOGY, GMCM 66

188. Lateral Corticospinal Tract
•80%ofpyramidalfiberscrosstooppositeside
•Descenddowninlateralfuniculusofspinalcord
DEPT. OF PHYSIOLOGY, GMCM 67

189. C.TerminationofLateralCST
•TerminatesatallspinalcordlevelsdirectlyonαMNs.
•LateralCST–makemonosynaptic direct
connectionstomotorneuronsonoppositeside
DEPT. OF PHYSIOLOGY, GMCM 68

190. •Controls distal limb muscles → concerned with fine
skilled movements
DEPT. OF PHYSIOLOGY, GMCM 69

191. Anterior Corticospinal Tract
•About20%fibersdonotcrossinmedulla
•Descenddowninanteriorfuniculusofspinalcord
DEPT. OF PHYSIOLOGY, GMCM 70

192. C.TerminationofAnteriorCST
•Mostoffiberscrossatthelevelofspinalcordwhere
theyterminate,butsomefibersremainuncrossed.
•AnteriorCST–connectwithinterneuronthatmake
connectionwithαmotorneurononbothsidesofbody
DEPT. OF PHYSIOLOGY, GMCM 71

193. •Controlsmusclesoftrunkandproximalmusclesof
limbs→concernedwithposturaladjustmentsand
grossmovements.
DEPT. OF PHYSIOLOGY, GMCM 72

195. Within the brainstem and spinal cord,
•Pathwaysandneuronsconcernedwithcontrolofaxial
muscles&proximallimbmusclesarelocatedmedially
orventrally.

196. Within the brainstem and spinal cord,
•Pathways&neuronsthatareconcernedwithcontrolof
musclesindistalportionsofthelimbsarelocated
laterally.

197. DEPT. OF PHYSIOLOGY, GMCM 76

198. C. Termination of CST
•Synapsewithαmotorneuroninanteriorhorndirectlyor
indirectlythroughinterneuron.
•Fewterminateonsensoryrelayneuronsindorsalhorn

199. •LateralCST–makemonosynapticdirectconnections
tomotorneuronsonoppositeside(esp.forskilled
movements)
•AnteriorCST–connectwithinterneuronthatmake
connectionwithαmotorneurononbothsidesofbody
DEPT. OF PHYSIOLOGY, GMCM 78

201. DEPT. OF PHYSIOLOGY, GMCM 80
*Draw thisdiagram for exam

202. NEXT CLASS!
[email protected]
DEPT. OF PHYSIOLOGY, GMCM 81

203. MOTOR
SYSTEM 4
DR SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM

204. Descending tracts or Motor pathways
1.Pyramidal tractorCorticospinal tractand
Corticobulbar orCorticonucleartract
2.Extra pyramidal pathways
•Reticulospinal, Vestibulospinal, Rubrospinal,
Tectospinal

205. DEPT. OF PHYSIOLOGY, GMCM 4
Specific Learning Objectives
•Corticobulbar / Corticonuclear Tracts
•Concept of LMN and UMN
•Functions of Pyramidal Tract
•Extrapyramidal System
•Functions of Extrapyramidal System
DEPT. OF PHYSIOLOGY, GMCM

206. Corticobulbar or Corticonucleartracts
Throughoutthebrainstem,fibersaregivenofffrom
pyramidaltracttothenucleiofmotorcranialnerves.

207. Corticobulbarneuronsendeitherdirectlyonthecranial
nervenucleiorontheirantecedentinterneuronswithin
thebrainstem.
DEPT. OF PHYSIOLOGY, GMCM 6

208. •Midbrain-3
rd
and 4
th
cranial nerve nuclei
•Pons -5
th
, 6
th
and 7
th
cranial nerve nuclei
•Medulla-9
th
,10
th
,11
th
and12
th
cranial nerve
DEPT. OF PHYSIOLOGY, GMCM 7

209. DEPT. OF PHYSIOLOGY, GMCM 8

210. DEPT. OF PHYSIOLOGY, GMCM 9

211. 1.Inmidbrain,corticobulbarfibersterminateinmotor
nucleiofCNIIIandIVbilaterally.
2.Inpons,corticobulbarfiberstomotornucleitoCNV
andVIbilaterally
DEPT. OF PHYSIOLOGY, GMCM 10

212. •CorticobulbarfiberstoCNVII→toupperandlowerpartof
contralateralmotornucleusandonlyupperpartof
ipsilateralmotornucleus.
3.Inmedulla,corticobulbarfiberstomotornucleiofCNIX,
X,XIbilaterallyandunilaterallytocontralateralmotor
nucleusCNXII.
DEPT. OF PHYSIOLOGY, GMCM 11

213. DEPT. OF PHYSIOLOGY, GMCM 12
Specific Learning Objectives
•Corticobulbar / Corticonuclear Tracts
•Concept of LMN and UMN
•Functions of Pyramidal Tract
•Extrapyramidal System
•Functions of Extrapyramidal System
DEPT. OF PHYSIOLOGY, GMCM

214. DEPT. OF PHYSIOLOGY, GMCM 13
Concept of LMN and UMN

216. Lower motor neuron (LMN)
•Spinalandcranialmotorneuronsthatdirectlyinnervate
muscles.
•Alphamotorneuronandthemotorpartofcranial
nerves.

217. Upper motor neuron (UMN)
•Neuronsinbrainandspinalcordthatactivateorinhibit
thealphamotorneuronorcorrespondingcranialnerve
nucleithroughthedescendingtracts.
•Pyramidaltractandextrapyramidaltracts

218. DEPT. OF PHYSIOLOGY, GMCM 17
Specific Learning Objectives
•Corticobulbar / Corticonuclear Tracts
•Concept of LMN and UMN
•Functions of Pyramidal Tract
•Extrapyramidal System
•Functions of Extrapyramidal System
DEPT. OF PHYSIOLOGY, GMCM

219. Functions of pyramidal tract
1.Voluntary motor function
A.Lateral corticospinal tract
•Main control of movements of distallimb muscles
•Initiation of skilled voluntarymovements
DEPT. OF PHYSIOLOGY, GMCM 18

220. B.Anterior corticospinal tract
•Movement of trunk and proximallimb muscles
•Posturaladjustments and gross movements
C.Corticobulbar fibers
•Supply muscles at face, eyes, tongue, larynx and
pharynx.
DEPT. OF PHYSIOLOGY, GMCM 19

221. 2.Formspathwayforsuperficialreflexes(abdominal
reflex,plantarreflex)
3.Somefiberstransmitinformationfrombrainto
afferentneuron,socanmodifyafferentinputs–
sensorymotorco-ordination.
DEPT. OF PHYSIOLOGY, GMCM 20

222. DEPT. OF PHYSIOLOGY, GMCM 21
Specific Learning Objectives
•Corticobulbar / Corticonuclear Tracts
•Concept of LMN and UMN
•Functions of Pyramidal Tract
•Extrapyramidal System
•Functions of Extrapyramidal System
DEPT. OF PHYSIOLOGY, GMCM

223. The Extrapyramidal System
Partsofnervoussystemexcludingmotorcortexand
corticospinalpathwaywhichareconcernedwith
movementandposture.
DEPT. OF PHYSIOLOGY, GMCM 22

224. Consists of
1.Basal ganglia
2.Cerebellar Nuclie
3.Reticular formation
4.Vestibular nuclei
5.Red nuclei
DEPT. OF PHYSIOLOGY, GMCM 23
6.Extrapyramidal tracts
•Tectospinal tract
•Pontine and medullary
reticulospinal tracts
•Vestibulospinal tract
•Rubrospinal tract

225. Extrapyramidal tracts
Alldescendingmotorpathwaysotherthanpyramidal
tract,concernedwithcontrolofmuscletone,posture
andequilibrium.
DEPT. OF PHYSIOLOGY, GMCM 24

226. DEPT. OF PHYSIOLOGY, GMCM 27
EXTRAPYRAMIDAL TRACTS
LATERAL BRAINSTEM PATHWAYS MEDIAL BRAINSTEM PATHWAYS
•Descend inipsilateral
anteriorfuniculus.
•Synapse at medial part of
anterior horn.
•Control axial and
proximal muscles.
•Descend inlateral
funiculus.
•Synapse at lateral part of
anterior horn.
•Control distal limb
muscles.

227. DEPT. OF PHYSIOLOGY, GMCM 28

228. DEPT. OF PHYSIOLOGY, GMCM 29
LATERAL BRAINSTEM PATHWAYS MEDIAL BRAINSTEM PATHWAYS

229. DEPT. OF PHYSIOLOGY, GMCM 30
EXTRAPYRAMIDAL TRACTS
LATERAL BRAINSTEM PATHWAYS MEDIAL BRAINSTEM PATHWAYS
VESTIBULOSPINAL
RETICULOSPINAL
TECTOSPINAL
RUBROSPINAL

230. DEPT. OF PHYSIOLOGY, GMCM 31

231. 1. Rubrospinal tract
•Arisefrommagnocellularportionofrednucleusin
midbrain.
•FiberscrosstotheoppositesideasForel’sdecussation.
•→ReticularformationofPons→Medulla→Spinalcord→
Anteriorhorncell

232. •Involvedinregulationofpostureandcoordination
•Concernedwithadjustmentsofdistallimbmuscles-
InfluenceαMNthatcontrolsdistallimbmuscleson
contralateralsideofbody
•Excitesflexormusclesandinhibitsextensormuscles
DEPT. OF PHYSIOLOGY, GMCM 33

233. 2. Tectospinal Pathway
•Fibers arise from tectum (superior colliculus) of mid brain
•Crossto opposite side →Reticular formation of Pons→
Medulla →Spinal cord →Anterior horn cell
•Receives mainly visual input.
•Control movements of head and eyes-regulates head
movements in response to visual stimuli.

234. 3. Vestibulospinal tract
•Originates from vestibular nucleus
•Stimulates αMN
•Function in association with pontine reticular nuclei to control
antigravity muscles.
DEPT. OF PHYSIOLOGY, GMCM 35

235. Lateral Vestibulospinal
•Arisesinthelowerponsinthelateralvestibularnucleus
•Descendinthespinalcordintheanteriorfuniculus
anteriortorubrospinaltract
•Fibersareuncrossed

236. •Projectsipsilaterallytoneuronsthatactivateantigravity
musclesatallspinallevels.
•Mediatesbodyposturaladjustmentsafterangularand
linearaccelerationsofhead.
DEPT. OF PHYSIOLOGY, GMCM 37

237. Medial Vestibulospinal
•Arises from lower pons in medial and inferior vestibular
nuclei
•Descend in the anterior funiculus –crossed & uncrossed

238. •Projectsbilaterallytocervicalspinalmotorneurons
thatcontrolneckmusculature.
•Mediatesadjustmentsinheadpositioninresponseto
angularacceleration.
DEPT. OF PHYSIOLOGY, GMCM 39

239. 4. Reticulospinal –Medial & Lateral
•Arisefromreticularformationofponsandmedulla
•Projecttoallspinallevels
•Terminatebothonalphamotorneuronandgamma
motorneuron
•Involvedinmaintenanceofpostureandmodulation
ofmuscletone.

240. Pontine (medial) reticulospinal tract
•Uncrossed tract
•Pontine reticular formation is spontaneously active.
•In addition, they receive strong excitatory signals from the
vestibular nuclei, as well as from deep nuclei of cerebellum.
DEPT. OF PHYSIOLOGY, GMCM 41

241. •Fibersofpontinereticulospinaltractterminateon
medialanteriormotorneuronsthatexciteaxial
antigravitymuscles.
•StimulateextensorγMN.
DEPT. OF PHYSIOLOGY, GMCM 42

242. Medullary (lateral) reticulospinal tract
•Crossedtract
•Medullaryreticularnucleireceivestronginputcollaterals
fromcorticospinaltract+rubrospinaltract+othermotor
pathways.
•Counterbalancestheexcitatorysignalsfromthepontine
reticularsystem.
DEPT. OF PHYSIOLOGY, GMCM 43

243. •Terminateonanteriormotorneuronsthatcontrol
antigravitymuscles.
•InhibitextensorγMN.
DEPT. OF PHYSIOLOGY, GMCM 44

244. DEPT. OF PHYSIOLOGY, GMCM 45
Specific Learning Objectives
•Corticobulbar / Corticonuclear Tracts
•Concept of LMN and UMN
•Functions of Pyramidal Tract
•Extrapyramidal System
•Functions of Extrapyramidal System
DEPT. OF PHYSIOLOGY, GMCM

245. Functions of Extrapyramidal system
1.Facilitate or inhibit voluntary movements
2.Control of posture and equilibrium
3.Control coordinated movements of body and limbs –
coordinated movements of arms and legs during sitting,
walking, running etc.

246. 4.Influenceγmotorneurondischarge:controlofmuscletone
1.Theyexerttonicinhibitorycontroloverlowercenters
2.Lesioncauseincreasedtone→Rigidityofmuscles
5.Causealterationsinrespiration,bloodpressure

247. Q
DEPT. OF PHYSIOLOGY, GMCM 48

248. Tractsconcernedwithadjustmentsoftrunkandproximal
muscles(posturaladjustmentsandgrossmovements)
1.Ventralcorticospinaltract
2.Othermedialdescendingtractsfrombrainstem-
tectospinal,reticulospinal,vestibulospinal
DEPT. OF PHYSIOLOGY, GMCM 49

249. Tractsconcernedwithdistallimbmuscles(fine,skilled
voluntarymovement)
1.Lateralcorticospinaltract
2.Rubrospinaltracts
DEPT. OF PHYSIOLOGY, GMCM 50

250. NEXT CLASS!
[email protected]
DEPT. OF PHYSIOLOGY, GMCM 51

251. MOTOR
SYSTEM 5
DR SARAN AJAY
DEPT. OF PHYSIOLOGY, GMCM

252. DEPT. OF PHYSIOLOGY, GMCM 3
Specific Learning Objectives
•Lesions of Corticospinal Tract
•Lesions of the extrapyramidal tract
•Reveiw Questions
DEPT. OF PHYSIOLOGY, GMCM

253. Lesions of Corticospinal Pathway
•Lossofabilitytoinitiatevoluntarymovements
•WhenlateralCSTisspecificallydamaged→lossof
abilitytocarryoutfinemovements.
•WhenventralCSTisdamaged→inabilitytoproduce
grossmovementslikewalking,climbingetc.

254. Mostlesionsofcorticospinalsystemdamagetheextra
pyramidalsystemalso.
DEPT. OF PHYSIOLOGY, GMCM 5

256. DEPT. OF PHYSIOLOGY, GMCM 7

257. •Lesionabovedecussation→lossofvoluntarymovement
onoppositesideofbody.
•AtCerebralCortex→Monoplegia(localizedparalysis
affectingonelimb).
DEPT. OF PHYSIOLOGY, GMCM 8

258. •AtInternalCapsule→Hemiplegia(paralysisofonehalf
ofbody)-becausethefibersarecloselypacked
•AtBrainstem→CrossedHemiplegiaoneormore
cranialnervesmaybeaffectedonthesideoflesion&
signsofUMNlesiononoppositeside.
DEPT. OF PHYSIOLOGY, GMCM 9

259. DEPT. OF PHYSIOLOGY, GMCM 10

260. •AtSpinalCord→Corticospinaltractmaybeaffected
bilaterally.
•Theleveloflesionisusuallydelineatedbyaccompanying
LMNlesionsigns.
DEPT. OF PHYSIOLOGY, GMCM 11

261. Dependingonthelevelofspinalcordlesion
•Paraplegia–bothlowerlimbsareparalyzed.
•Quadriplegia–Allfourlimbsareparalyzed.
DEPT. OF PHYSIOLOGY, GMCM 12

262. DEPT. OF PHYSIOLOGY, GMCM 13

263. Hemiplegia
1.Paralysis of one half of body
2.Lesion of Pyramidal tract
3.Site of lesion –Internal capsule
4.Usuallycausedbythrombosisorhemorrhagein
lenticulostriatebranchofmiddlecerebral
artery.

265. DEPT. OF PHYSIOLOGY, GMCM 16

266. DEPT. OF PHYSIOLOGY, GMCM 17

267. 5.UMNtypeoflesion
6.Inacutestateusuallytherearesignsofshock-
Hypotonia,noreflexmovements
7.After2-3weekssignsoftypicalUMNlesion
appear.

268. Clinical Features
1.Power
•Unilateral paralysis –one half of the body –Hemiplegia
•Sometime only weakness is seen –Hemiparesis
•Lower part of faceis involved
•Mouth deviates to opposite side of lesion
•Upper part of face escapes –bilateral representation

269. DEPT. OF PHYSIOLOGY, GMCM 20

270. DEPT. OF PHYSIOLOGY, GMCM 21

271. 2.Tone
•In pure pyramidal tract lesion hypotonia is seen.
•Usually Pyramidal and Extrapyramidal tracts are damaged
resulting in spasticity –Spastic Paralysis
•Spasticity →Clasp knife effect
•Due to operation of stretch reflex and then inverse stretch
reflex.
DEPT. OF PHYSIOLOGY, GMCM 22

273. 3.Deep tendon reflexes:
•Exaggerated(Hyperreflexia)
•Clonus may be present
4.Superficial reflexes:
•Usually absent
•Plantar reflex –Positive Babinski sign
DEPT. OF PHYSIOLOGY, GMCM 24

274. Positive Babinski sign
•Extensor plantar response
•It is a flexor withdrawal reflex that is normally held in
check by the lateral corticospinal system.

275. •Damagetothelateralcorticospinaltractproducesthe
PositiveBabinskisigninresponsetothisstimulation.
•Dorsiflexionofthegreattoeandfanningoftheother
toes.
DEPT. OF PHYSIOLOGY, GMCM 26

276. DEPT. OF PHYSIOLOGY, GMCM 27

277. 5.Bulk:
•Gross muscle wasting is absent
•Only slight disuse atrophy
6.Speech:
•Dysarthria–due to weakness or incoordination of the
muscle of face, pharynx, lips, tongue or palate.
DEPT. OF PHYSIOLOGY, GMCM 28

278. 7.Gait
•Pyramidal gait/ Hemiplegic gait
•Circumduction
DEPT. OF PHYSIOLOGY, GMCM 29

279. DEPT. OF PHYSIOLOGY, GMCM 30

280. Crossed Hemiplegia
Crossedhemiplegia–hereparalysisofmuscles
suppliedbythecranialnervesonsamesideand
hemiplegiaonoppositeside.
DEPT. OF PHYSIOLOGY, GMCM 31

281. •Midbrain–3
rd
&4
th
cranialnervesaredamaged(LMN
lesion)→paralysisofocularmusclesonsameside.
•Pons–cranialnerves5,6&7areaffected.(LMNlesion)
•Medulla–9,10,11&12cranialnervesareaffected→vital
centersmaygetaffected→death
DEPT. OF PHYSIOLOGY, GMCM 32

282. DEPT. OF PHYSIOLOGY, GMCM 33

283. Spinal cord lesion
•Pyramidal tract on both sides are damaged
•Usually paralysis of both lower limbs -Paraplegia
•If at the level of cervical spine –Quadriplegia/ Tetraplegia

285. Cerebral Palsy
•Nonprogressiveneurologicdisorder.
•Occurbeforeorduringchildbirthorduringearlychildhood.
•Exposureofdevelopingbraintohypoxia,infections,or
toxins.
•Morecommoninprematurebabies.

286. 1. Motor deficits
•Spasticity, ataxia
•Deficits in fine motor control
•Abnormal gait (crouched or “scissored gait”)
DEPT. OF PHYSIOLOGY, GMCM 37

287. 2. Sensory deficits
•Loss of vision and hearing
3. Learning difficulties and seizures
DEPT. OF PHYSIOLOGY, GMCM 38

288. DEPT. OF PHYSIOLOGY, GMCM 39
Specific Learning Objectives
•Lesions of Corticospinal Tract
•Lesions of the extrapyramidal tract
•Reveiw Questions
DEPT. OF PHYSIOLOGY, GMCM

289. Diseases affecting Extrapyramidal system
•Characterized by difficulty in initiatingvoluntarymovements.
•Appearanceof involuntary movements.
•Impairmentof balancing and orienting reflexes.
•Alterationof muscle tone.
•Muscle strength is usually unaffected

290. DEPT. OF PHYSIOLOGY, GMCM 41
Specific Learning Objectives
•Lesions of Corticospinal Tract
•Lesions of the extrapyramidal tract
•Reveiw Questions
DEPT. OF PHYSIOLOGY, GMCM

291. DEPT. OF PHYSIOLOGY, GMCM 42
KUHS 2021

292. DEPT. OF PHYSIOLOGY, GMCM 43
KUHS 2020

293. DEPT. OF PHYSIOLOGY, GMCM 44
KUHS 2014

294. DEPT. OF PHYSIOLOGY, GMCM 45
KUHS 2013

295. DEPT. OF PHYSIOLOGY, GMCM 46
KUHS 2021

296. One-word answers
1.The receptor for inverse stretch reflex is ……. 2021
2.In spinal cord the dorsal root is sensory and the ventral root is motor, this
law is called ……… 2021
Short Essay (5 marks)
1.Draw a diagram to show the origin, course and termination of Corticospinal
tract 2019
DEPT. OF PHYSIOLOGY, GMCM 47

297. Physiological basis
1.Clasp Knife Rigidity. 2014
2.Babinski’s Sign in newborn. 2015
3.Abnormal plantar in neurological diseases. 2016
4.Cogwheel Rigidity. 2017
5.UMN Lesions produce hypertonia. 2018
6.Pyramidal Tract Lesions produces exaggerated deep tendon reflexes. 2019
DEPT. OF PHYSIOLOGY, GMCM 48

298. Answer briefly
1.Stretch Reflex 2013
Draw and label:
1.Stretch and Inverse Stretch Reflex. 2012
2.Corticospinal/ Pyramidal Tract. 2011, 2016, 2019, 2020
3.Functional areas of cerebral cortex. 2014, 2020
DEPT. OF PHYSIOLOGY, GMCM 49

299. DEPT. OF PHYSIOLOGY, GMCM
1
[email protected]