1. (GENERAL SOMATIC EFFERENT/
SOMATOMOTORIC
SYSTEM
Somatomotoric
cortex
(GENERAL SOMATIC EFFERENT/
GSE SYSTEM)
Prof. S. Aswin, MD, PhD

2. GENERAL SOMATIC EFFERENT (GSE) SYSTEM BASAL GANGLIA/ CEREBELLUM/
PYRAMIDAL
SYSTEM
EFFECTOR
(SKELETAL MUSCLE)
(INFO.)
(CONTRACTION)
COORDINATED
MOVEMENT
(instruction:
CONSCIOUS)
CNS
(BRAIN)
CIRCUIT
EXTRAPYRA-
MIDAL
SYSTEM
BASAL GANGLIA/ CEREBELLUM/
THALAMUS/
CORTEX

3. GENERAL FUNCTIONS & CHARACTERISTICS OF GSE SYSTEM
1. SKELETAL MUSCLE
SKELETAL MUSCLES GENERALLY FUNCTION TO ALLOW:
MOVEMENT
ADJUST POSTURE
PRODUCE BODY HEAT
THE CRUCIAL PROPERTIES OF THE MUSCLE TISSUE:
ITS ABILITY TO CONTRACT
BE EXCITED BY A STIMULUS
BE STRETCHED (RETURN TO ITS ORIGINAL SHAPE AFTER STRETCHING OR CONTRACTING)
GIVES SKELETON THE POWER TO MOVE
IS USUALLY CONTRACTED VOLUNTARILY AND CONSCIOUSLY
(Except: reflex)

4. *(MN: motor neuron; NMJ: neuromuscular junction; MEP: motor-end plate)
2. NERVOUS CONTROL
(MNs, NMJ/MEP)*
THE CONTRACTION OF SKELETAL MUSCLE IS UNDER NERVOUS CONTROL, i.e., THE MUSCLE TISSUE ALONE CANNOT CONTRACT
*(MN: motor neuron; NMJ: neuromuscular junction; MEP: motor-end plate)
3. NEUROTRANSMITTER
ITS CONTRACTION IS INITIATED BY A CHEMICAL (NEUROTRANSMITTER/NT: acetylcholin/ACh) RELEASED FROM A NERVE (NEURON) AXON TERMINAL

5. (Area 4/motor stript/ motor homunculus) LCS: LAT. CORTICOSPIN. TRACT
SOMATOMOT. CORTEX: UMN
Corticobulbar tract
CST
Somatomotoric cortex
BULBUS
LMN
SKELETAL
MUSCLE
SKELETALMUSCLE
MOTOR HOMUNCULUS
LCS
UMN
(Area 4/motor stript/ motor homunculus)
ACS
SKELETALMUSCLE
LMN
SKELETAL MUSCLE
ANT. HORN
CST: CORTICOSPIN. TRACT
LCS: LAT. CORTICOSPIN. TRACT
ACS: ANT. CORTICOSPIN. TRACT
MIDLINE

6. Somatomotoric cortex
MOTOR HOMUNCULUS

7. STRUCTURAL & FUNCTIONAL ASPECTS OF THE GSE SYSTEM
 THE BRAIN EXERTS ACTIVE AND SUBTLE INFLUENCE ON THE ACTIVITY OF SKELETAL MUSCLES THROUGH DESCENDING MOTOR PATHWAYS THAT MAKE UP THE UPPER MOTOR NEURONS (UMN)
1. UMN
ORIGINATING FROM CELL BODIES IN THE
CEREBRAL CORTEX AND BRAINSTEM
(Regulates/modulates)
FUNCTION: UMN LMN* (cranial/spinal nerves)
*LMNs located in the BULBUS (pons + medulla), their fibers are sent (through cranial/spinal nerves) to the muscle fibers innervated
Cortex: UMN
Skeletal m.
Bulbus:LMN.

8. Ant. horn of the spinal cord
Skeletal m.
LMN
Ant. horn of the spinal cord
Alpha MN
Gamma MN
2. LMN**
ALPHA MNs EXTRAFUSAL MUSCLE FIBERS
GAMMA-EFFERENT MNs INTRAFUSAL MUSCLE FIBERS
** LMNs located in the anterior horn of the spinal cord (through the spinal nerves) sent to the muscle fibers innervated

9. Fig.10.7 NEUROMUSCULAR SPINDLE SENSORY RECEPTOR THAT MONITORS THE EXTENT AND RATE OF MUSCLE LENGTHENING (STRETCHRECEPTOR)
Gamma- efferent MN
Alpha MN
Neuromuscular spindle
(fusus neuromuscularis)
Soma cells of gamma efferent MN and alpha MN located in the anterior horn of the spinal cord

11. Motor neuron together with muscle fibers (myofibers) it innervates
MOTOR UNIT
Motor neuron together with muscle fibers (myofibers) it innervates
NEUROMUSCULAR JUNCTION (NMJ)/
MOTOR-END PLATE (MEP):
The junctin of a motor unit and muscle fibers
In humans:
A single motor unit causes the contraction of 6-30 fibers (small MU: in some eye muscles) to over 1,000 fibers (large MU: in powerful leg muscles)

12. CHARACTERISTICS OF MOTOR UNIT (MU) SMALL MU: Fast movement
Weak movement
Easily fatigue
(e.g., external eye muscles)
LARGE MU:
Slow movement
Strong movement
Not easily fatigue
(e.g., muscles of upper arm and upper leg/thigh)

13. NEUROMUSCULAR JUNCTION (NMJ) (Fig.10.5)
THE JUNCTION BETWEEN A MOTOR NEURON ENDING ON A MUSCLE FIBER
THE END BRANCHES OF THE MOTOR NEURON (AXON TERMINALS) GAIN ACCESS TO THE MUSCLE FIBER THROUGH THE ENDOMYSIUM
AT THE JUNCTION BETWEEN THE MUSCLE FIBER AND THE AXON TERMINALS: THE MUSCLE FIBER MEMBRANE FORMS A MOTOR END PLATE (MEP)
(MEP:
THE SPECIALIZED PORTION OF THE SARCOLEMMA (PLASMA MEMBRANE) OF A MUSCLE FIBER
IT SURROUNDS THE SYNAPTIC END BULBS OF THE AXON)

14. MEP

15. NEUROMUSCCULAR JUNCTION
MEP

16. Electrochemical process
Action potential NT release interaction of NT + receptor
MEP

17. COMPONENTS OF THE MOTOR SYSTEM: PYRAMIDAL & EXTRAPYRAMIDAL
CEREBRAL CORTEX
Pyramidal syst. BG
Extrapyr. syst.
THAL. BG
Basal ganglia
Ext. amyg., HPT
Cere-
bell.
BRAIN STEM
Cerebellum, BG, thalamus: involve in the extrapyramidal circuits that influence pyramidal activities
SPINAL CORD

18. Cerebral cortex efferent (descendens) pathways
MOTOR AREA (4,6+8, 3,1,2, 5,7)
Cerebral cortex efferent (descendens) pathways
1.Corticobulbar tract
2. Corticorubral
2. Corticonuclear
3. Corticospinal tract
Cerebral cortex 1 2
Bulbus 3
Nuc. ruber
Nuc. cran.
Ant. horn of
the spin. cord
MIDLINE

19. CORTICOBULBAR TRACT
Cerebral cortex
Bulbus
Pons
Med.oblongata

20. 1A. Anterior corticospinal tract (10% of fibers)
1B. Lateral corticospinal tract (pyramidal tract)
(90% of fibers) 1
pyramis
Pyramidal
decussation 1B 1A

21. Bulbus: medulla oblongata + pons
Med. obl.
Bulbus: medulla oblongata + pons

22. LOWER MOTONEURONS (LMNs)*
SOMATOMOTORIC SYSTEM
PYRAMIDAL SYST.
EXTRAPYRAMIDAL SYST.
INITIATION
VOLUNTARY
NONSTEREOTYPIC
(specific, smooth, precise, skilled)
INDIVIDUAL MUSCLE
MOVEMENT
BODY POSITION (rough)
TONUS
INHIBITION/ACTIVATION
GROUP OF MUSCLES
MOVEMENT*
LOWER MOTONEURONS (LMNs)*
SKELETAL MUSCLES
* e.g., extensors, flexors
COORDINATED MOVEMENT
(* LMN: Motoric neuron which axon directly innervate the effector/skeletal muscle)

23. BASAL GANGLIA/NUCLEI 2B
1. Lenticular nuc.:
Globus pallidus
Putamen
2. Caudate nuc.:
A. Caput
B. Corpus
C. Caudate
3. Amygdala 2A 1 2C 3

24. * Pyramidal areas/cortex (4, 3,1,2,6,8, 5,7)
PYRAMIDAL SYSTEM
PART OF SOMATOMOTORIC SYST. ORIGINATED FROM SPECIAL AREAS* OF THE CEREBRAL CORTEX WHICH DESCENDS THROUGH THE PYRAMID/PYRAMIS OF THE MEDULLA OBLONGATA AND TERMINATES ON MOTONEURON
* Pyramidal areas/cortex (4, 3,1,2,6,8, 5,7)

25. CYTOARCHITECTURAL MAP OF THE HUMAN CEREBRAL CORTEX (52 AREAS)
Somatomotoric cortex/area
Primary (Motor stript): 4
Secundary/premotoric: 6,8
Supplement:

26. MOTOR CORTEX (MC)
Primary MC
(voluntary movement)
2. Supplementary MC
(programming of complex movement)
3. Premotor cortex
(complex movement) 2 1 3

27. Motor representation of the various parts of the body
MOTOR HOMUNCULUS
Motor representation of the various parts of the body
Different parts of the body are represented in the cortex according to their functional importance
(Note the large areas devoted to the fingers, thumb, and face)
SENSORY HOMUNCULUS

28. THE COMPONENTS OF THE PYRAMIDAL SYST.
SOMATOMOTORIC CORTEX CONTRIBUTION
SOMATOMOTORIC CORTEX
AREA %
(MOTOR STRIPT)
HOMUNCULUS MOTORIS
AREA 3,1, %
(SOMAESTHETIC AREA)
AREA 6,8
(PREMOTORIC AREA) 40%
AREA 5,7
(PARASENSORIC AREA)

29. MOTOR UNIT

30. UPPER MOTONEURON (UMN) & LOWER MOTONEURON (LMN)
CEREBRAL CORTEX
MESENCEPHALON
BRAIN STEM
THE LOCATION OF ITS CELL BODY (SOMA)
1. CEREBRAL CORTEX (Area 4; 6,8; 3,1,2;5,7)
Corticospinal tract Corticobulbar tract
Bulbus
Spinal cord
(Anterior horn)

31. SPINAL CORD (Anterior horn)
2. MESENCEPHALON
RUBER NUC.
TECTAL NUC.
INTERSTITIAL NUC.
Rubrospinal Tectospinal Interstitiospinal
tract tract tract
SPINAL CORD (Anterior horn)
3. BRAIN STEM (truncus cerebri): Bulbus (Pons + med. Obl.)
RETICULAR NUC.
VESTIBULAR NUC.
Reticulospinal Vestibulospinal
tract tract
SPINAL CORD

32. LOWER MOTONEURON (LMN)
THE LOCATION OF ITS CELL BODY
1. BRAIN STEM
MOTORIC NUCLEI OF CERTAIN CRANIAL NERVES
(N III, N IV, N V, N VI, N VII, N IX, N X, N XII)
N III
N IV EXTRAOCULAR MUSCLES
N VI
N V
N VII BRANCHIOGENIC MUSCLES *
N IX VISCERAL ARCH I, II and III
N X
N XII TONGUE MUSCLES
(* BRANCHIOGENIC MUSCLES:
- Facial/mimic muscles - Sternocleidomastoid
- Platysma - Laryngeal muscles
- Trapezius - Pharyngeal muscles)

33. EXTRAFUSAL MUSCLE FIBERS INTRAFUSAL MUSCLE FIBERS
2. ANTERIOR HORN OF THE SPINAL CORD
Alpha MN
Gamma MN
EXTRAFUSAL MUSCLE FIBERS
INTRAFUSAL MUSCLE FIBERS

34. SOMATOMOTORIC (DESCENDENT) SYSTEM
MOTOR CORTEX (UMN) A B
LMN
BULBUS C
UMN
LMN
SPINAL CORD
(Anterior horn)
MUSCULAR
ACTIVITY
(MOVEMENT) D
A: CORTICOSPINAL TRACT D: SPINAL NERVES
B: CORTICOBULBAR TRACT
C: RETICULOSPINAL TRACT
VESTIBULOSPINAL TRACT
INTERSTITIOSPINAL TRACT

35. PYRAMIDAL SYSTEM CORTICOSPINAL TRACT CORTICOBULBAR TRACT
(PYRAMIDAL TRACT)
LATERAL ANTERIOR
(CROSSED)
90%) (10%)

36. PYRAMIDAL SYSTEM PYRAMIDAL CORTEX CRUS CEREBRI
CORTICOSPINAL (MIDBRAIN)
TRACT
PONS
PYRAMIS
(MED. OBLONGATA)
PYR. DECUSSATION
LATERAL CORTICOSPINAL
ANTERIOR CORTICOSPINAL
LMN (ANTERIOR HORN OF
THE SPINAL CORD)
Lamina Rexed IV, V, VI, VII, IX
LMN
(ANT. HORN OF
THE SPINAL CORD
(LAM. REXED VIII)
MIDLINE
REXED LAMINA I II
III IV V VI
VII IX
VIII X

37. CORTICOBULBAR TRACT UMN PYR. CORTEX CORTICOBULBAR TRACT PONS BULBUS
MED. OBL.
LMN 1 2
Characteristics of the bulbar nuclei innervation
In general: crossed + uncrossed
1 & 2: nuclei in the bulbus

38. LMN IN THE BULBUS MOTORIC NUCLEI OF:
N III, N IV, N VI EXTRAOCULAR MUSCLES
N V MASTICATORY MUSCLES
N VII FACIAL (MIMIC) MUSCLES
N IX, N X PALATUM MOLLE MUSCLES
PHARYNGEAL MUSCLES (cranial
LARYNGEAL MUSCLES part)
ESOPHAGUS
N XI TRAPEZIUS
STERNOCLEIDOMASTOID (caudal
PHARYNGEAL MUSCLES
N XII TONGUE MUSCLES

39. CORTICOBULBAR TRACT A B (right) (left) CEREBRAL CORTEX CEREBRAL CORTEX
(UMN) (UMN)
IPSILAT.
(uncrossed)
A: BILATERAL
CONTRALAT.
(crossed)
B: UNCROSSED
(UNILATERAL)
Innervation of nuclei
in the bulbus A B

40. CHARACTERISTICS OF CORTICOBULBAR TRACT
IN GENERAL: CRANIAL NERVE NUCLEI RECEIVE
BILATERAL INNERVATION FROM
THE CEREBRAL CORTEX
EXCEPTIONS:
- N VI: CROSSED ONLY (CONTRALATERAL)
CORTEX
A.CRANIAL (bilateral)
- N VII: 2 NUCLEI
B. CAUDAL (contralateral)
CORTEX
N VII NUCLEI
Upper facial muscles
Lower facial muscles
N VI NUCLEUS A B

41. CLINICAL CORRELATION PLEGIA PARALYSIS/PLEGIA PARESIS
(TOTAL PARALYSIS) (PARTIAL PARALYSIS)
Severed A B Severed A B
MONOPLEGIA HEMIPLEGIA PARAPLEGIA TETRAPLEGIA
(One limb) (Half of the (Right + left (Four limbs)
body: lower limbs)
one upper limb
(the same side)
one lower limb
MUSCLE
PLEGIA

42. PARALYSIS / PLEGIA PYRAMIDAL TRACT LESION
RIGHT (DEXTER) LEFT (SINISTER)
A CORTICOSPINAL TRACT
PYRAMIDAL DECUSSATION C
LATERAL
CORTICOSPINAL TRACT
B D
SUPERIOR EXTREMITY
INFERIOR EXTREMITY
LESION:
A LEFT HEMIPLEGIA
(HEMIPLEGIA SINISTRA) / CONTRALATERAL
B RIGHT HEMIPLEGIA / IPSILATERAL
C LEFT INFERIOR EXTREMITY PARALYSIS
RIGHT SUPERIOR EXTREMITY PARALYSIS
(HEMIPLEGIA CRUCIATA)
LEFT SUPERIOR EXTREMITY
LEFT INFERIOR EXTREMITY
RIGHT SUPERIOR EXTREMITY
RIGHT INFERIOR EXTREMITY D
TETRAPLEGIA

43. BROWN-SEQUARD SYNDROME
HEMISECTION OF THE SPINAL CORD
IPSILATERAL PARALYSIS
DEEP ANESTHESIA
+ CUTANEOUS IPSILATERAL
HYPERESTHESIA
CONTRALATERAL CUTANEOUS ANESTHESIA

44. LESION AT THE LATERAL PART OF PYR. DECUSSATION
Hemiplegia cruciata

45. HEMISECTION OF THE SPINAL CORD
BROWN-SEQUARD
SYNDROME:
Paralysis (ipsilat.)
Deep anesthesia
& cutaneous hyperesthesia (ipsilat.)
- Cutaneous anesthesia (contralat.)

46. Hemiplegia

47. EXTRAPYRAMIDAL
SYSTEM

48. EXTRAPYRAMIDAL S Y S T E M
A SYSTEM CONSISTS OF TRACTS (SUPRASPINAL DESCENDENS), NUCLEI AND FEEDBACK CIRCUITS
WHICH PRODUCES SIGNIFICANT INFLUENCES ON
THE VOLUNTARY MUSCLES ACTIVITIES, OUTSIDE
OF THE PYRAMIDAL SYSTEM
THE COMPONENTS OF THE EXTRAPYRAMIDAL SYSTEM
EXTRAPYRAMIDAL CORTEX TELENCEPHALON
BASAL GANGLIA
THALAMUS DIENCEPHALON
SUBTHALAMUS
RUBER NUCLEUS
SUBSTANTIA NIGRA BRAIN STEM
RETICULAR FORMATION
CEREBELLUM
FEEDBACK CIRCUITS

49. EXTRAPYRAMIDAL SYSTEM PYRAMIDAL SYSTEM
POSTURAL ACTIVITY NONPOSTURAL ACTIVITY
GROUP OF LARGE INDIVIDUAL MUSCLE
MUSCLES ADAPTATION SKILLED MOVEMENTS
(Smooth, precise, specific,
learned)
MODULATION
CIRCUIT
LMN
Pyramidal & extrapyramidal systems interact in harmony to produce normal and coordinated movement
NORMAL & COORDINATED
MOVEMENT

50. GANGLIA BASALIA AMYGDALA: Anatomically: part of basal ganglia
Functionally: part of the limbic system
GANGLIA BASALIA
NUC. LENTICULARIS
PUTAMEN
GLOBUS PALLIDUS
NUC. CAUDATUS
CAPUT
CORPUS
CAUDA

51. Head of caudate nuc.
Putamen
Claustrum
Globus pallidus
Internal capsule
Thalamus

52. Lateral corticospinal tract
Ventral corticospinal tract
Lateral corticospinal tract

53. DOMAINS OF THE EXTRAPYRAMIDAL SYSTEM
ROUGH SYNERGIC MOVEMENT
POSTURAL ADAPTATION
LOCOMOTION
SEMIAUTOMATIC MOVEMENT
(WALKING: THE SWAY OF ARMS AND LEGS)
FACE EXPRESSION
EXTRAPYRAMIDAL CORTEX:
OVERLAPS WITH THE CORTEX OF THE PYRAMIDAL SYSTEM

54. THE INFLUENCE OF THE EXTRAPYRAMIDAL SYSTEM ON LMN ACTIVITY
INDIRECT (via pyramidal cortex)
DIRECT (to LMN)
PYRAMIDAL
SYSTEM
EXTRAPYRAMIDAL
SYSTEM
PYRAMIDAL CORTEX EXTRAPYRAMIDAL CORTEX
1 c a
THALAMUS
LMN BASAL GANGLIA
2 b
SUBCORTICAL NUC.
EXTRAPYRAMIDAL CIRCUIT
(a, b and c)
RIGIDITY
DISORDER
(LESION) DYSKINESIA
CIRCUIT
VOLUNTARY
MOTORIC
ACTIVITY

55. TWO DIFFERENT PATHWAYS THROUGH THE BASAL GANGLIA: DIRECT & INDIRECT
CORTEX
GABA/Enkephalin (glutamate)
GLOBUS STRIATUM
PALLIDUS (Ach) Dopamin
GABA/
Subst. P SUBST NIGRA
(p. compacta)
GABA Glutamate
SUBTHALAMIC GLOBUS SUBST. NIGRA
NUC. PALLIDUS (p. reticularis)
Glutamate (GABA)
THALAMUS
SUPPLEMENTARY
MOTOR AREA

56. CLINICAL CORRELATION RIGIDITY DISORDER OF THE EXTRAPYRAMIDAL SYST.
DYSKINESIA
RIGIDITY INCREASED OF THE TONUS
OF AGONIST AND ANTAGONIST
MUSCLES
PLASTIC COGWHEEL
RESISTANCE: + RESISTANCE: +
SMOOTH AND JERKY
CONTINUOUS (DISCONTINUOUS)
PASSIVE MOVEMENT
TEST

57. ► COGWHEEL RIGIDITY ► WALKING/GAIT:
DYSKINESIA
(ABNORMAL INVOLUNTARY MOVEMENT,
WITHOUT PARALYSIS)
RHYTHMIC ARHYTHMIC
ATHETOSIS BALLISMUS
CHOREA
PARKINSON’S DISEASE
(PARALYSIS AGITANS)
LESION: - SUBSTANTIA NIGRA
- STRIATUM/GLOBUS PALLIDUS
SYMPTOMS
► COGWHEEL RIGIDITY ► WALKING/GAIT:
► DIFFICULTY IN THE INITIATION SHORT STEPS
OF MOVEMENT HEAVILY
► POVERTY OF MOVEMENT ► FINE TREMOR
(BRADYKINESIA)/SLOW RESTING
► MASK FACE PILL ROLLING

58. Parkinson’s disease

59. *Dopamine cannot pass through blood-brain barrier (BBB)
THERAPY
SURGICAL LESION OF DECREASED OF TREMOR
GLOBUS PALLIDUS/ AND RIGIDITY
VENTRAL THALAMIC NUC.
DRUG
L-DOPA LOW DOSE  RIGIDITY
(Precursor of dopamine*)
HIGH DOSE  TREMOR
*Dopamine cannot pass through blood-brain barrier (BBB)

60. ATHETOSIS of distal musculatures of extremities (hands, feet)
LESION: PUTAMEN
(birth trauma)
SYMPTOMS
Slow, sinuous, aimless movements
of distal musculatures of extremities
(hands, feet)
Alternate adduction-abduction (shoulder joints)
Alternate flexion-extention (wrist, fingers)
Hyperextension of fingers

62. CHOREA (‘dance’) LESION: STRIATUM CEREBRAL CORTEX
THE MOVEMENT OF THE EXTREMITIES
(THE AXIAL AND PROXIMAL LIMBS MUSCULATURES):
- SINUOUS - PURPOSELESS
- JERKY - RAPID
- IRREGULAR
(OCCURS WHEN ALERT DISAPPEARS WHEN SLEEP)
Ex. : HUNTINGTON’S CHOREA
HEREDITARY
BEGINS AT THE AGE OF 30
AGE GETTING WORSE AND WORSE
FATAL
CHOREOATHETOSIS: COMBINATION OF CHOREA & ATHETOSIS
SYMPTOMS

63. CONGENITAL CHOREOATHETOSIS
Spasmodic dyskinesia
Congenital cho-
reoathetosis
Paralysis
Agitans
(Parkinson’s
Disease)
CONGENITAL CHOREOATHETOSIS
PARKINSON’S
DISEASE
ATHETOTIC MOVEMENT
Athetosis
ATHETOSIS

64. BALLISMUS SYMPTOMS ABNORMAL INVOLUNTARY MOVEMENT
(‘ballistic’: throwing)
SUDDEN, FLAILING* AND
GROSS MOVEMENTS
LESION: SUBTHALAMIC NUC.
(CONTRALATERAL)
(* memukul/mencambuk)
SYMPTOMS
ABNORMAL INVOLUNTARY MOVEMENT
(STRONG AND RAPID)
PROXIMAL MUSCULATURES OF THE LIMBS
DECREASED MUSCLE TONUS
DISAPPEARS WHEN SLEEP
UNILATERAL USUALLY CALLED: HEMIBALLISMUS