Transcript Basal Ganglia YAYDAR 2012-2013

Basal Nuclei (Ganglia)
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Basal nuclei
• Applied to a collection of masses of gray
matter situated within each cerebral
hemisphere.
• They are paired and located between
thalamus and white matter.
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Consists of 5 pairs of nuclei:
These are:
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Caudate nucleus
Putamen
Globus pallidus
Substantia nigra
Subthalamic nucleus
Basal Nuclei (Ganglia)
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Basal nuclei
• Consists of 5 pairs of nuclei:
These are:
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Caudate nucleus
Putamen
Globus pallidus
Substantia nigra
Subthalamic nucleus
Basal Nuclei (Ganglia)
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Consists of 5 pairs of nuclei:
These are:
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Caudate nucleus
Putamen
Globus pallidus
Substantia nigra
Subthalamic nucleus
Basal Nuclei (Ganglia)
Basal Nuclei (Ganglia)
Basal Nuclei (Ganglia)
Basal Nuclei (Ganglia)
Basal Nuclei (Ganglia)
Basal Nuclei (Ganglia)
Caudate
nucleus
Globus
pallidus
Putamen
Corpus
striatum
Nuclei Basales (Ganglia Basale)
Caudate
nucleus
Putamen
Striatum
Cerebellum (Latin for Little Brain)
Nuclei Basales (Ganglia Basale)
Putamen
Globus
pallidus
Lentiform
nucleus
Basal Nuclei (Ganglia)
Basal Nuclei (Ganglia)
Neostriatum
Caudate
nucleus
Putamen
Paleostriatum
Globus
pallidus
Archistriatum
Amygdaloid
body
Basal Nuclei (Ganglia)
Nuclei Basales (Ganglia Basale)
Basal Nuclei (Ganglia)
Function of Basal Nuclei
Basically the activity of basal nuclei begins by information received from
sensory cortex, thalamus, substantia nigra, and red nucleus, according to
thoughts of mind.
• These information is integrated within corpus striatum and channeled
within globus pallidus and outflow back to motor areas of cerebral
cortex, and other motor areas in brain stem.
• Thus the basal nuclei can control muscular movement through its
effect on cerebral cortex.
• So basal nuclei assist in regulation of voluntary movement and
learning of motor skills.
Functions of Basal Nuclei
• 1- Design of plans, which convert thoughts and ideas
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into motor actions: to produce a coordinated organized
purposeful movement.
e.g. dressing.
Determining the timing and scale of movement: to what
extent the movement will be fast, and how long it will
last.
Storage of motor programs of familiar motor actions:
e.g. signature.
Functions of Nuclei Basales (Ganglia Basale)
 The basal ganglia are associated with a
variety of functions, including :
Voluntary motor control
Procedural learning relating to routine
behaviors or "habits" such as bruxism
(gnashing of teeth), eye movements, and
cognitive, emotional functions.
 Action selection, that is, the decision of
which of several possible behaviors to
execute at a given time.
Basal ganglia exert an inhibitory influence
on a number of motor systems, and that a
release of this inhibition permits a motor
system to become active.
Basal Nuclei (Ganglia)
Nuclei Basales (Ganglia Basale)
Caudate Nucleus
• Large C-shaped or comma-shaped mass of grey matter.
• Lies in close relation to lateral ventricle.
• It has a Head, Body, and Tail.
Caudate Nucleus
• Large C-shaped or comma-shaped mass of grey matter.
• Lies in close relation to lateral ventricle.
• It has a Head, Body, and Tail.
Caudate Nucleus
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Head :( Anterior) Large, & rounded
and forms the lateral wall of anterior
horn of lateral ventricle.
• It is continuous inferiorly with putamen
of lentiform Nucleus.
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Body : Long &narrow continuous with
head at the interventricular foramen.
• It forms part of the floor of body of
lateral ventricle.
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Tail : Long & narrow, and lies in the
roof of inferior horn of lateral ventricle.
• It is connected anteriorly with
Amygdaloid nucleus.
Caudate Nucleus
Caudate Nucleus
Caudate Nucleus
Connections of Corpus Striatum
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Afferent Fibers ( Input):
• I- Corticostriate Fibers: From all parts of cerebral cortex (mostly from
sensory- motor cortex) axons pass to caudate nucleus and putamen.
• Glutamate is the neurotransmitter of this fibers.
• II-Thalamostriate Fibers : From intralaminar nuclei of thalamus axons
pass to caudate nucleus and putamen.
• III- Nigrostriate Fibers : Axons from Substantia nigra of midbrain pass
to caudate nucleus and putamen.
• Neurotransmitter is Dopamine.
• IV_Brain stem Strial Fibers : Ascending fibers from brain stem end in
caudate nucleus & putamen.
• Serotonin is the neurotransmitter.
• It is believed that the last 2 groups are inhibitory in function.
Efferent Fibers (Output)
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Striatopallidal fibers:
• These fibers pass from corpus striatum (caudate nucleus &
putamen) to globus pallidus.
• Gamma-aminobutyric acid (GABA) is the neurotransmitter.
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Striatonigral fibers:
• These fibers pass from caudate nucleus & putamen to Substantia
nigra.
• Some fibers use GABA as a neurotransmitter, and others use
substance p.
Lentiform Nucleus
• It is a mass of grey matter wedge-shaped
or (biconvex lens).
• It has 2 capsules, external capsule laterally
& internal capsule medially.
• Internal capsule separates between
lentiform nucleus laterally & caudate
nucleus and thalamus medially.
• External capsule separates between
lentiform nucleus and Claustrum.
Lentiform Nucleus
• It is divided into putamen & globus
pallidus.
• Putamen: Larger darker lateral
portion.
• Globus pallidus : Smaller, lighter
medial portion.
• Inferiorly putamen is continuous with
the head of caudate nucleus.
Lentiform Nucleus
• It is divided into putamen & globus
pallidus.
• Putamen: Larger darker lateral
portion.
• Globus pallidus : Smaller, lighter
medial portion.
• Inferiorly putamen is continuous with
the head of caudate nucleus.
Basal Nuclei (Ganglia)
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Substantia nigra
• Located in midbrain between
cerebral crus and
tegmentum.
• Looks dark owing to melanin
pigment containing neurons..
• Consists of two parts:
• Pars compacta
• Pars reticularis
Substantia Nigra
Pedunculus cerebri
Aquaductus mesencephali
Pc
Pr
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
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Tr. corticospinalis
Tr. corticonuclearis
Substantia Nigra
Cross section obtained from the level of superior colliculus
Nucleus tractus mesencephalici
nervi trigeminalis
Strata (grisea et alba) colliculi superioris
Nucleus oculomotorius accessorius
Lemniscus medialis
Substantia nigra,
Pars compacta
Nucleus ruber
Fibrae parietotemporopontinae
Fibrae corticonucleares
Substantia nigra, Pars reticularis
Fibrae frontopontinae
Fila radicularia nervi oculomotorii
Substantia Nigra
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
Substantia Nigra
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Afferents:
• Most come from neostriatum.
• Most of the afferent fibers terminate in SNPR, but some end in SNPC
as well.
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
Substantia Nigra
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Efferents:
• Pars compacta contains
dopaminergic neurons.
• Efferents arising from
SNPC terminate in
neostriatum.
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
Substantia Nigra
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Efferents:
• Pars reticularis’contains
GABAergic neurons.
• Efferents arising from
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SNPR terminate in:
:
• Thalamus
• Superior colliculus
• Tegmental nucleus
• Pedunculopontine
nucleus
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
Basal Nuclei (Ganglia)
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Subthalamic nucleus
• The most lower nucleus of the
subthalamus.
• Extents to transition zone
between the tegmentum of the
midbrain and subthalamus.
• Located dorsolateral upper end
of the SN, medial to the internal
capsule, and in upper lateral
part of the thalamus.
Subthalamic Nucleus
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Afferents
• GPE
• Centromedian nucleus
• Parafascicular nucleus
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Tegmental nucleus
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Pedunculopontine
nucleus
Subthalamic Nucleus
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Afferents
• GPE
• Centromedian nucleus
• Parafascicular nucleus
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Tegmental nucleus
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Pedunculopontine
nucleus
Subthalamic Nucleus
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Efferents
• GPe and GPi
• Substantia nigra
Subthalamic Nucleus
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Efferents
• GPe and GPi
• Substantia nigra
Nucleus Subthalamicus
Connections of Basal Nuclei (Ganglia)
Nuclei
Basales of
Bağlantıları
Connections
Basal Nuclei (Ganglia)
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Importants features:
• Efferents from cerebral cortex
to striatum are activator (use
glutamate).
• Neurons in the striatum are
inhibitory in nature..
• Neurons in the SNr and
GPm are also inhibitory in
nature.
• Efferents of the thalamus
stimulate the cerebral cortex.
Connections of Basal Nuclei (Ganglia)
 Direct pathway:
 Cortical cells project excitatory inputs
onto the thalamus through the
inhibitory ansa lenticularis pathway.
 The striatal inhibition of the SNr-GPi
complex coupled with SNr-GPi
inhibition of the thalamus therefore
results in a net reduction of inhibition of
the thalamus via the striatum.
GABA
GABA
 The SNr-GPi complex projects directly
Glutamate
to the striatum, which in turn projects
inhibitory neurons onto the cells of the
SNr-GPi complex.
Glutamate
Connections of Basal Nuclei (Ganglia)
 Direct pathway:
 The thalamus projects excitatory
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GABA
GABA
Glutamate
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glutamatergic neurons to the cortex
itself.
The direct pathway, therefore, results
in the excitation of the motor cortex by
the thalamus. Once stimulated, the
cortex projects its own excitatory
outputs to the brain stem and ultimately
muscle fibers via the lateral
corticospinal tract.
The following diagram depicts the
direct pathway:
Glutamate
 Cortex (stimulates) → Striatum (inhibits) → "SNr-GPi" complex (less
inhibition of thalamus) → Thalamus (stimulates) → Cortex (stimulates) →
Muscles, etc. → (hyperkinetic state)
Connections of Basal Nuclei (Ganglia)
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Importants features:
• Efferents from cerebral cortex
to striatum are activator (use
glutamate).
• Neurons in the striatum are
inhibitory in nature..
• Neurons in the GPl are also
inhibitory in nature.
• Neurons in the STN are
activator in nature.
• Efferents of the thalamus
stimulate the cerebral cortex.
Connections of Basal Nuclei (Ganglia)
 Indirect pathway:
neurons in the indirect pathway project
inhibitory axons onto the cells of the
globus pallidus externa (GPe), which
tonically inhibits the subthalamic nucleus
(STN).
 This inhibition (by the striatum) of the
inhibitory projections of the GPe, results
in the net reduction of inhibition of the
STN.
GABA
 Once stimulated by the cortex, striatal
GABA
Glutamate
Also starts from neurons in the striatum.
Glutamate

Connections of Basal Nuclei (Ganglia)
 Indirect pathway:
 The STN, in turn, projects excitatory
thalamus and, therefore, decreased
stimulation of the motor cortex by the
thalamus and reduced muscle activity.
 The direct and indirect pathways are
therefore antagonist in their functions.
GABA
GABA
 The end-result is inhibition of the
Glutamate
inputs to the SNr-GPi complex (which
inhibits the thalamus).
Glutamate
Connections of Basal Nuclei (Ganglia)
 Indirect pathway:
 Following is a diagram of the indirect
Glutamate
GABA
GABA
Cortex (stimulates) → Striatum (inhibits)
→ GPe (less inhibition of STN) → STN
(stimulates) → "SNr-GPi" complex
(inhibits) → Thalamus (is stimulating less)
→ Cortex (is stimulating less) → Muscles,
etc. → (hypokinetic state)
Glutamate
pathway:
Connections of Basal Nuclei (Ganglia)
Connections of Basal Nuclei (Ganglia)
Connections of Basal Nuclei (Ganglia)
A man with Parkinson's
disease displaying a flexed
walking posture pictured in
1892. Photo appeared in
Nouvelle Iconographie de la
Salpètrière, vol. 5.
Connections of Basal Nuclei (Ganglia)
Manifestation of Lesion of Basal Nuclei
• I- Involuntary movement during rest: Chorea, athetosis,
hemiballismus, and tremor.
• II- Changes in muscle tone.
• A- Chorea: (Dance). Lesion: in caudate N
• Features: Involuntary, quick, Jerky, irregular, nonrepetitive and
purposeless movement :
e.g. Swift grimaces, and sudden movement of head or limb.
Types: Sydenham (rheumatic fiver) more in female, Huntington’s,
(hereditary), chorea Gravidarum, or chorea of contraceptive pills.
Huntington’s Chorea
Parkinsonism, Parkinson Disease
• Lesion: Neuronal degeneration in substantia nigra leading to
reduction of dopamine within corpus striatum.
• Features:
1- Tremors: Pill-rolling, involuntary, rhythmic, oscillating
movements. It occurs during waking time during rest, it is
called static tremors.
2- Rigidity: It occurs in both flexors, and extensors, but more in
flexors giving flexion attitude.
It is called lead pipe rigidity.
3- Akinesia: it means lack of movement; Absence of swinging
arm during walking, mask face, low- volume slow
monotonous speech, and shuffling gait.
Parkinsonism, Parkinson Disease
Basal Ganglia
Cerebellum
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resting tremor
postural instability
festination
rigidity
masked facies
bradykinesia
dyskinesia
torticollis
chorea
athetosis
hemiballismus
akathisia
intention tremor
dysmetria
dysdiadochokinesia
hypotonia
heal to shin
finger to nose
rebound
ataxic gait
titubation
nystagmus
dysmetric saccades
COMPARISON OF MOTOR SYSTEMS
http://library.med.utah.edu/neurologicexam/html/home_exam.html
Lower Motor Ne uron
S pi n al C ord
Upper Motor Ne uron
C orticospin la Tract
C ere bel lum
Basal Gan gli a
Efferent part of
mon osyn apticreflex
Volu n tary moveme n t
Muscle t one by
inhibiting antagonists
Maintains muscle
fibers (trophic fact ors)
Muscle t one
Rapid coordi n ate dalternating
skil le d moveme n ts that are
learned
Eye-head movements
Facilitate sinte n tion al
moveme n ts an d in h ibit
extran e ou smoveme n ts
Aut opilot for motor activities
Normal
Weakness or paralysis
Fine control, espec. finger
flexors
Inhibit ory to Lower motor
neurons
Weakness or paralysis
Posture and Gait
Balance, equilibrium,
orientation in space
timing, duration, and amplitude
Voluntary movements in an
aut omatic manor.
Hyperreflexi a
Hyperactive deep tendon
reflexes
Babin ski- extensor plantar
reflex
S pasticity
Tru n cal ataxi a, gait ataxi a
S h ufflin gor fe stin at
in g gait,
small steps, hard to turn
Nystagmu s, Diz zin e ss,
Maske d facie s, few blinks
Decomposition of movement
Difficulty t urning or starting,
h ypokin e tic= bradykin e sia
P aucity of associated
movements
Abn ormal
Areflexi a
Fasciculation
Muscle Atroph y
Flaccid paralysis
Dysme tri a- ataxia of arms
Dysynergia
Dysdi adoch koin e sia
- inability
t o do rapid alternating
movements
Hypotonia- pendular reflexes
In te n tiontremor
Scanning speech
C h ore a, ath e tosis
,
hyperkinetic
Rigidi ty( lead-pipe )
(cogwheel),
Re stin g remor
t
Soft speech
BASAL GANGLIA AND CONTROL OF MOTOR
FUNCTIONS
Cerebral
Cortex
Cerebral
Cortex
CEREBRAL
CORTEX
BASAL GANGLIA
Corticospinal tracts
THALAMIUS
Corticobulbar tracts
BRAIN STEM
CEREBELLUM
Bulbospinal tracts
SENSORY INPUT
SPINAL CORD
FINAL COMMON PATH
BASAL GANGLIA
COMPONENTS
FUNCTIONAL ANATOMY
BASAL GANGLIA
THE BASAL GANGLIA ARE MASSES OF GREY
MATTER MADE OF CELL BODIES LYING DEEP
INSIDE THE WHITE MATTER OF THE CEREBRUM,
AND MAKES UP PART OF THE MIDBRAIN.
An upper mass is called the caudate nucleus,
is separated from a lower mass, the lentiform
nucleus. The lentiform nucleus consists of
the putamen and the globus pallidus. Other
nuclei include the substantia nigra and
subthalamic nucleus.
Basal
Nuclei
Caudate
Nucleus
Lenticular
Nucleus
Corpus
Striatum
Putamen
Globus Pallidus
Subthalamic Nucleus
Substantia Nigra
BASAL GANGLIA
CONNECTIONS
Connections for Motor Control
3 Connections to remember
1. Main input to the basal ganglia
2. Main output from the basal ganglia
3. Connections between parts of basal ganglia
Basal
Nuclei
Caudate
Nucleus
Corpus
Striatum
Putamen
Lentiform
Globus Pallidus
Subthalamic Nucleus
Substantia Nigra
MAIN INPUT TO THE BASAL GANGLIA
That comes from the cerebral cortex (motor area) and
projects to the NEOSTRIATUM
(a term for the caudate nucleus and putamen)
THE MAIN OUTPUT
Is via the thalamus to the cerebral cortex
(motor area)
The Putamen Circuit
The Caudate Circuit
Basal Ganglial Pathways
Loops
↑ MOTOR
Direct Basal Ganglial
Pathway
GLU
+
GLU
+
↓GABA
-
Thalamus
Thalamocortical Neurons
are disinhibited
GPe
GPi
-
St
+
DA1+
GABA
SThN
SNPC
↓ MOTOR
Indirect Basal Ganglial
Pathway
GLU
↑GABA
+
GPe
-
St +
GPi
Thalamus
GLU
Subthalamic Neurons
are disinhibited
GLU
GABA
-
+
DA2 -
- ↓GABA
SThN
SNPC
BASAL GANGLIA
FUNCTIONS
• Control of movements
• Planning and programming of
movements
• Cognition
The Putamen Circuit
Executes Learned Patterns of Motor Activity
• Basal ganglia function in association with the corticospinal
system to control complex patterns of motor activity.
• Examples are:
– writing of letters of the alphabet.
– cutting paper with scissors,
– hammering nails,
– shooting a basketball through a hoop,
– passing a football,
– throwing a baseball,
– the movements of shoveling dirt,
– most aspects of vocalization,
– controlled movements of the eyes
– virtually any other of our skilled movements, most of
them performed subconsciously.
The Caudate Circuit
Cognitive Control of Sequences of Motor Patterns
• Cognition means the thinking processes of the brain,
using both sensory input to the brain plus information
already stored in memory. Thoughts are generated in
the mind by a process called cognitive control of
motor activity.
• Example:A person seeing a lion approach and then
responding instantaneously and automatically by (1)
turning away from the lion, (2) beginning to run, and
(3) even attempting to climb a tree.
• Thus, cognitive control of motor activity determines
subconsciously, and within seconds, which patterns
of movement will be used together to achieve a
complex goal
The Caudate Circuit
Change the Timing and to Scale the Intensity of Movements
• Two important capabilities of the brain in
controlling movement are
– (1) to determine how rapidly the movement is
to be performed and
– (2) to control how large the movement will be.
• For instance, a person may write the letter "a"
slowly or rapidly. Also, he or she may write a
small "a" on a piece of paper or a large "a" on a
chalkboard. Regardless of the choice, the
proportional characteristics of the letter remain
nearly the same
Movement Disorders
Hyperkinetic
•Hemiballismus
•Huntington’s
Disease
•Athetosis
Hypokinetic
•Parkinson’s Disease
•Drug Induced (Neuroleptics, MPTP)
Movement
Disorder
Features
Lesion
Chorea
Multiple quick, random
movements, usually most
prominent in the
appendicular muscles
Atrophy of the striatum.
Huntington Chorea
Athetosis
Slow writhing
movements,which are
usually more severe in the
appendicular muscles
Diffuse hypermyelination
of corpus striatum and
thalamus
Hemiballismus Wild flinging movements of
half of the body
Hemorrhagic destruction
of contralateral
subthalamic n.
Hypertensive patients
Parkinsonism
Degenration of Substantia
Nigra
Pill rolling tremor of the
fingers at rest, lead pipe
rigidity and akinesia
Parkinson’s Disease
• Described by James Parkinson
• Degeneration of dopaminergic nigrostriatal
neurons (60-80 %).
• Phenothiazines (tranquilizers drugs) .
• Methyl-Phenyl-Tetrahydro-Pyridine (MPTP). The
oxidant MPP+ is toxic to SN.
• Five cardinal features
– Tremor
– Rigidity
– Akinesia & Bradykinesia
– Postural Changes
– Speech Changes
PARKINSON'S DISEASE
RESTING TREMORS
RIGIDITY LEAD PIPE & COG WHEEL
MONOTONUS SLURRED ANARTHRIA
ABSENCE OF ASSOCIATED UNCONCIOUS
MOVEMENTS(SWINGING OF ARMS DURING
WALKING .
FACIAL EXPRESSION IS MASKED
SIMIAN POSTURE
SWEATING
TREATMENT: L-DOPA
Huntington’s Disease
CORTEX
Glutamate (+)
PUTAMEN
GABA (-)
GP externa
Glutamate (+)
GABA (-)
STN
Glutamate (+)
GP interna
GABA (-)
VA/VL THALAMUS
+
Huntington’s Disease
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Hereditory , autosomal dominant
Rare onset at 30-40s as early as 20s
Disease of caudate & putamen.
Early, Jerky movement of hands toward end
of reaching an object
Later, hyperkinetic choreiform movements
appear and gradually increase until they
incapacitate the patient
Slurred speech and incomprehensive
Progressive Dementia
Loss of GABA nergic neurons
Hemiballismus
CORTEX
Glutamate (+)
PUTAMEN
GABA (-)
GP externa
Glutamate (+) GABA (-)
STN
Glutamate (+)
GP interna
GABA (-)
VA/VL THALAMUS
+
Hemiballismus
• Injury usually to subthalamic
nucleus STN
• Decreased inhibition (Indirect
Pathway)
• Characterized by uncontrolled
flinging
• TX: Dopamine Antagonist
Left basal ganglia affect the right
side of the body.
Cerebral cortex
UMN
Pyramidal
decussation
LMN
Basal Ganglia
Thalamus