Transcript Basal Ganglia

Basal ganglia
CORPUS
STRIATUM
Caudate
nucleus
Claustram
Lentiform
nucleus
Putamen
Globus
palidus
Internal
External
Amygdaloid
body
Basal Ganglia (traditional concept)
Corpus striatum
lenticular nucleus
putamen
globus pallidus
caudate nucleus
Amygdaloid body
Basal Ganglia
3
2
2
1
1
4
3
Basal Ganglia
2
1
3
2
1
3
CORPOUS STRIATUM
Neostriatum
or striatum
Dorsal
Caudate
nucleus
putamen
Ventral
Nucleus
accumbance
Paleostriatum
or pallidum
Dorsal
Globus
pallidus
Ventral
Substantia
nigra
inominate
Basal Ganglia
Introduction
Traditional Concepts of Basal Ganglia
Corpus Striatum
Caudate Nucleus
Lenticular Nucleus
Neostriatum
Putamen
Globus Pallidus
Corpus Amygdaloideum
Striatum
Paleostriatum
Archistriatum
Pallidum
Lateral surface
of basal ganglia
1. Putamen
2. Tail of caudate nucleus
3. Caudatolenticular gray
bridge
4. Amygdaloid body
5. thalamus
Basal Ganglia
Connections
Input Portion
STRIATUM
(Caudate Nucleus and Putamen)
Output Portion
1. PALLIDUM (Globus Pallidus)
2. SNr (Substantia Nigra, Pars Reticulata)
Basal Ganglia
Connections
STRIATUM
Afferents from
1. Cerebral Cortex [Corticostriatal Projection]
2. Thalamus (CM-PF complex) [Thalamostriatal Projection]
3. SNc (Substantia Nigra, pars compacta),
Ventral Tegmental Area (VTA, A10)
and A8(Retrorubral Area) [Nigrostriatal Projection]
4. Dorsal Raphe Nucleus (B6, B8) [Raphestriatal Projection]
5. Amygdaloid Nuclear Complex [Amygdalostriatal Projection]
Efferents to
1. Pallidum (GPi & GPe) [Striopallidal Projection]
2. SNr [Strionigral Projection]
3. SNc from striosome
An oblique section through the diencephalon and basal ganglia. Abbreviations: A8, 9, 10,
dopaminergic cell groups; AL, ansa lenticularis; CL, centrolateral nucleus of thalamus; cm,
centromedian nucleus of thalamus; EX, external pallidal segment; FS, fasciculus
subthalamicus; H, H1, H2, subthalamic fields of Forel; ICV, internal cerebral veins in the
transverse fissure; INT, internal pallidal segment; ITA, interthalamic adhesion; MFB, media
forebrain bundle; SLIC, sublentiform internal capsule; 3, 3rd ventricle.
Connections of the striatum. The major afferent projections to the striatum are
shown on the left and major efferent projections from the striatum on the righ
Major interconnections of the basal ganglia.
Input-Output
Relationship
of Basal Ganglia
1. striopallidal fiber
2. strionigral fiber
3. strionigral fiber
from striosome
to SNc
4. ventrostrioventro-pallidal fiber
Basal Ganglia
Connections
PALLIDUM (Globus Pallidus)
Afferents from
1. Striatum [Striatopallidal Projection]
2. STN <GPi & GPe> [Subthalamopallidal Projection]
Efferents to
1. Thalamus (VLo, VApc, CM) <GPi> [Pallidothalamic Projection]
2. STN <GPe> [Pallidosubthalamic Projection]
SNr (Substantia Nigra, Pars Reticulata)
Afferents from Striatum [Striatonigral Projection]
Efferents to
1. Thalamus (VLm, VAmc, MD) [Nigrothalamic Projection]
2. Brain Stem Nucleus: Tectum (Superior Colliculus) &
Pedunculopontine Nucleus (PPN)
Basal Ganglia
Connections
Pallidothalamic Fibers
from GPi to VLo, VApc, CM
Ansa Lenticularis
from outer (lateral) portion of GPi
fibers sweep ventromedially and rostrally around
the posterior limb of the internal capsule
enters Forel’s field H
Lenticular Fasciculus
from inner (medial) portion of GPi
perforate internal capsule
enters Forel’s field H2
Thalamic fasciculus
ansa lenticularis, lenticular fasciculus
and cerebellothalamic fibers
Forel’s field H1
Basal Ganglia syndromes
Hyperkinetic
•
•
•
•
•
Chorea
Athetosis
Ballism
Dystonia
tourrette
Hypokinetic
• Parkinsonism
‫ رفت‬: ‫پارکينسون‬
R: Rigidity
A: Akinasia
F: Flex Posture, falling-freezing
T: Tremor
Basal Ganglia
Functional Consideration
Functional Consideration
1. Selection of “Preprogramed (learned) motor plans”
Basal Gangla Circuit ---- Selection Mechanism
Selection Inability -------- Akinesia and Hypokinesia
Faulty Selection ----------- Hyperkinesia
2. Generation (learning) of motor programs
Programming of several motor fragments into
complex motor routines
Cerebral Palsy ------------- Disordered motor program
SYDENHAM’S CHOREA
Clinical Feature
Principal Pathologic Lesion: Corpus Striatum
- Complication of
Rheumatic Fever
- Fine, disorganized , and
random movements of
extremities, face and
tongue
- Accompanied by
Muscular Hypotonia
- Typical exaggeration of
associated movements
during voluntary activity
- Usually recovers
spontaneously
in 1 to 4 months
HUNTINGTON’S CHOREA
Clinical Feature
- Predominantly autosomal dominantly
inherited chronic fatal disease
(Gene: chromosome 4)
- Insidious onset: Usually 40-50
- Choreic movements in onset
- Frequently associated with
emotional disturbances
- Ultimately, grotesque gait and sever
dysarthria, progressive dementia
ensues.
Principal Pathologic Lesion:
Corpus Striatum (esp. caudate nucleus)
and Cerebral Cortex
HEMIBALLISM
Clinical Feature
Lesion: Subthalamic Nucleus
- Usually results from CVA
(Cerebrovascular Accident)
involving subthalamic nucleus
- sudden onset
- Violent, writhing, involuntary
movements of wide excursion
confined to one half of the body
- The movements are continuous
and often exhausting but cease
during sleep
- Sometimes fatal due to exhaustion
- Could be controlled by
phenothiazines and stereotaxic
surgery
Parkinson’s Disease
PD
Disease of mesostriatal
dopaminergic system
Muhammad Ali in Alanta Olympic
normal
Parkinson’s Disease - Paralysis Agitans
Substantia Nigra,
Pars Compacta (SNc)
DOPAminergic Neuron
Clinical Feature (1)
Slowness of Movement
- Difficulty in Initiation and Cessation
of Movement
Parkinson’s Disease
Paralysis Agitans
Clinical Feature (2)
Resting Tremor
Parkinsonian Posture
Rigidity-Cogwheel Rigidity