1. Extrapyramidal pathway
Dr nabila tounsi

2. Extra-pyramidal tracts
are all descending tracts,
- Origin: start nearly from most areas of the CC mainly from area 6, 8,1,2 , area 3,and also area 5,but with connection with other sub-cortical areas : basal ganglia, reticular formation, vestibular nuclei, red-nuclei and olivary nuclei.
- Types of extrapyramidal tracts: Rubro-spinal tract , Tecto-spinal tracts, Reticulo-spinal tracts, Vestibulo-spinal tracts , Olivo-spinal tract
Rehabilitation Science Dept.
Dr. Nabila Tounsi

3. Anatomy review: Basal ganglia
Basal ganglia consists of a group of subcortical nucleis: Striatum(= caudate,+ putamen), globus pallidus (= pallidum)
Rehabilitation Science Dept.
Dr. Nabila Tounsi

4. Rehabilitation Science Dept.
Dr. Nabila Tounsi

5. { Anatomy review: Basal ganglia Input: striatum
Output: globus pallidus & substantia nigra
Rehabilitation Science Dept.
Dr. Nabila Tounsi

6. Basal ganglia Composed of caudate nucleus + lentiform nucleus:
Striatum = caudate nucleus + putamen.
Pallidum = globus pallidus.
Putamen + globus pallidus = lentiform nucleus.
Controls large subconscious movements of the skeletal muscles.
The globus pallidus regulates muscle tone.
Rehabilitation Science Dept.
Dr. Nabila Tounsi

7. Circuitry of the basal ganglia
Rehabilitation Science Dept.
Dr. Nabila Tounsi

8. Direct Basal Ganglia Circuit
Motor cortex projects to putamen:
Excitatory (glutamate)
Putamen projects to output nuclei (globus pallidus internus and substantia nigra reticularis):
Inhibitory (GABA and substance P)
Rehabilitation Science Dept.
Dr. Nabila Tounsi

9. Dopamine Neuronal System
Consists of nigrostriatal fibers
From pars compacta of substantia nigra
To striatum
Dopaminergic
Rehabilitation Science Dept.
Dr. Nabila Tounsi

10. Lateral brain stem pathways
Goal-directed limb movements, e.g. reaching, manipulation
Main path is
rubrospinal
From red nucleus
Crosses midline in brain stem
Influence distal muscles
Rehabilitation Science Dept.
Dr. Nabila Tounsi

11. -Rubro-spinal tract:
Origin: From the red nucleus in the midbrain. This tract crosses to the opposite side and descends in the lateral column of the spinal cord.
Functions:
-   Inhibitory to MT.
-   It acts as an additional pathway for transmission of the cortical motor orders to the lower motor neurons.
Rehabilitation Science Dept.
Dr. Nabila Tounsi

12. Medial brain stem pathways
Basic postural
control
Tectum
Tectospinal tract
Vestibular nucleus
Reticulospinal tract
Vestibulospinal tract
Influence axial & proximal muscles
Rehabilitation Science Dept.
Dr. Nabila Tounsi

13. Tecto-spinal tracts: 1 -I) Lateral Tecto-spinal tract:
-Origin: Superior colliculus in the tectum of the midbrain (which receives visual impulses) this tract crosses to the opposite side and descends in the cervical segments of the spinal cord.
-Functions: It is responsible for visual attack and defensive reactions.
Defensive reactions:
-   Closure of the eyes, raising the hands in front of the face and turning the head away to avoid the source of injury. .
Attack reactions:
-   Turning the head towards a beautiful sight.
Rehabilitation Science Dept.
Dr. Nabila Tounsi

14. Tecto-spinal tracts: 2 -II) Ventral tecto-spinal tract:
-Origin: Inferior colliculus in the tectum of the midbrain (which receives auditory impulses). This tract crosses to the opposite side and descends in the cervical segments of the spinal cord.
-Functions: It is responsible for auditory attack and defensive reactions.
-Defensive reactions:
-   Running away when a person hears the sound of a car behind him.
-Attack reactions:
-   Turning the head towards the source of a familiar sound.
Rehabilitation Science Dept.
Dr. Nabila Tounsi

15. Reticulo-spinal tracts
a) Lateral reticulo – spinal tract:
Origin: Reticular formation in the medulla. This tract crosses to the opposite side.
Function: Inhibition of MT.
b) Ventral reticulo-spinal tract:
Origin: Reticular formation in the pons. The tract passes in the same side.
Function: Facilitation of MT.
Rehabilitation Science Dept.
Dr. Nabila Tounsi

16. Vestibulo-spinal tracts:
Origin: Vestibular nuclei in the medulla. Both lateral and ventral vestibule- spinal tracts pass in the same side of the spinal cord.
Functions: Facilitation of MT, control of equilibrium, and maintain posture
Rehabilitation Science Dept.
Dr. Nabila Tounsi

17. Olivo-spinal tract:
Origin: Inferior Olivary nucleus in the medulla oblongata. This tract descends in the same side of the spinal cord.
Function: Facilitation of MT
Rehabilitation Science Dept.
Dr. Nabila Tounsi

18. Functions of extra-pyramidal tracts:
1) Regulation of equilibrium and maintain posture
2) Fixation movements
3) Associated movements
4) Coordination of movements:
Rehabilitation Science Dept.
Dr. Nabila Tounsi

19. Parkinson disease: Basal ganglia circuitry
Abnormal functioning
Rehabilitation Science Dept.
Dr. Nabila Tounsi

20. Extrapyramidal disorders
Basal nuclei set organism’s level of responsiveness to stimuli.
Extrapyramidal disorders are associated with basal nuclei pathology:
Negative symptoms of underresponsiveness:
Akinesias
i.e. Parkinson disease
Positive symptoms of over-responsiveness:
Choreas, athetoses, ballisms
i.e. Huntington’s chorea
Rehabilitation Science Dept.
Dr. Nabila Tounsi

21. Parkinsonism
Parkinsonism: elderly; degeneration of basal ganglia; bradykinesia, rigidity, resting tremor, and impairments of posture, balance, and gait, calcul, concentration
-MT: +++, plastic
-Akinesia
LOCUS NIGER
Rehabilitation Science Dept.
Dr. Nabila Tounsi

22. Chorea
CHOREA: is Involuntary, rapid, irregular, jerky movements; clinical feature of Huntington’s disease.”
Cara by: hypotonia, bilateral, may be interest the face, the neck, upper limb or low limbs, or associate between those
Rehabilitation Science Dept.
Dr. Nabila Tounsi

23. chorea :2
1-Huntington’s disease: inherited; adults; fatal; degeneration of basal ganglia and cerebral cortex; dementia, chorea, and disturbances of tone, posture, and gait.
2-Sydenham’s chorea: infectious; children; self-limiting; rheumatic fever; chorea, disturbances of balance and gait, and impairments of speech and memory
Rehabilitation Science Dept.
Dr. Nabila Tounsi

24. Athetosis Or athetoid movements :
“Slow, involuntary, writhing, twisting, “wormlike” movements; clinical feature of cerebral palsy.”
-Hypo or hypertonia
-Syncinesia: imitation of movement
-reflexes
- Choreoathetosis= Chorea + athetosis
Rehabilitation Science Dept.
Dr. Nabila Tounsi

25. Ballismus
-Ballismus: is Sudden, jerky, forceful, wild, flailing, motions ,if interest one side of the body= Hemiballismus
Rehabilitation Science Dept.
Dr. Nabila Tounsi

26. Rehabilitation Science Dept.
Dr. Nabila Tounsi