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Basal Ganglia Anatomy and Functions
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5. Basal Ganglia
Dr. Sai Sailesh Kumar G
Associate Professor
Department of Physiology
R.D. Gardi Medical College, Ujjain, Madhya Pradesh.
Email: dr.goothy@gmail.com
7. Functional anatomy
Corpus striatum is further divided into
Caudate nucleus
Lentiform nucleus
Lentiform nucleus is further divided into outer part-putamen and
inner part-globus pallidus
Globus pallidus is further divided into inner and outer segments
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10. Functional anatomy
The structure, functions and connections of putamen and
caudate nucleus is same so they both collectively called as
striatum or neo striatum
Striatum = Caudate nucleus + Putamen
Globus pallidus send major efferents of basal ganglia so it is
called as pallidum or paleo striatum
11. Functional anatomy
Claustrum is present between putamen and insular cortex
Its functions are not properly known
Amygdaloid body is connected with limbic system and discussed
along with limbic system
Subthalamic nucleus is present lateral to hypothalamus
Substansia nigra consists of pars reticularis and pars compacta
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15. Functional anatomy
Basal ganglia consists of
Caudate nucleus
Lentiform nucleus ( GP and Putamen)
Subthalamic nucleus
Sunstantia Nigra ( Pars compacta and pars reticularis)
16. Afferent connections
Cortico-striate fibers
All parts of cerebral cortex send axons to the caudate nucleus
and putamen
The largest input is from the sensory-motor cortex
Glutamate is the neurotransmitter
18. Afferent connections
Nigrostriate fibers
Neurons in the substantia nigra send axons to the caudate
nucleus and putamen
Dopamine is neuro transmitter
These fibers are inhibitory in function
19. Afferent connections
Brainstem striatal fibers
Ascending fibers from brain stem end in the caudate nucleus and
putamen
Serotonin is neurotransmitter
These fibers are inhibitory
21. Efferent connections
Striatopallidal fibers
Pass from caudate nucleus and putamen to globus pallidus
Gamma aminobutyric acid (GABA) as neuro transmitter
22. Efferent connections
Striato nigral fibers
Pass from caudate nucleus and putamen to substantia nigra
GABA or Ach or substance P as neurotransmitter
26. Striatonigral and nigrostriate pathways
Striatonigral pathway – Neuro transmitter is GABA- inhibitory
Neurotransmitter
Nigro striate pathway neurotransmitter is dopamine which is an
inhibitory neurotransmitter to the striatum.
Striato nigral pathway indirectly stimulates the striatum by
inhibiting dopamine release
27. Striatonigral and nigrostriate pathways
Cortico striate pathway- glutamate is N.T ( stimulatory)
Thalamo striate pathway – glutamate is N.T ( stimulatory)
Nigro striate pathway- dopamine is N.T ( inhibitory)
The interplay between these N.T helps to regulate the muscle
tone and also block involuntary movements during the execution
of a particular act.
28. Functions
The precise functions of basal ganglia is not properly known.
Basal ganglia is an accessory motor system that functions in
close association with cerebral cortex and cortico spinal motor
control systems
Helps to plan and control complex patterns of muscle
movements
Example writing alphabets
29. Functions
Example writing alphabets
When basal ganglia damaged, ones writing becomes crude as if
one were learning how to write for the first time
Other patterns that need basal ganglia are cutting paper with
scissors, hammering nails, shooting a basketball, passing a
football, throwing a baseball, vocalization, controlled movements
of eyes any other skilled movements.
30. Putamen circuit
1. From premotor and supplementary motor areas of motor cortex and
somatosensory areas of sensory cortex to putamen
2. From putamen to the internal portion of GP
3. From GP to venteroanterior and venterolateral nucleus of thalamus
4. From thalamus to primary motor cortex and premotor and
supplementary motor areas of cortex
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32. Putamen circuit
Helps to execute learned pattens of movements
How?
Little is known about this function
Damage of circuit, certain patterns of movements becomes abnormal
Lesion of GP, leads to spontaneous and continuous writing
movements of hand, arm, neck and face.
These movements are called athetosis
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34. Putamen circuit
Lesion to subthalamic nucleus, sudden flailing movements of
entire limb, called as hemiballismus
Multiple small lesions in putamen leads to flickering movements
in hands, face and other parts of body, called as chorea.
Lesion to substantia nigra leads to common and extremely
severe disease called Parkinson’s disease.
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36. Caudate circuit
Signals pass from cerebral cortex to caudate nucleus
Next transmitted to the internal globus pallidus
Then to relay nucleus of venteroanterior and ventero lateral nucleus of
thalamus
Finally back to the prefrontal, premotor and supplementary motor
areas of cerebral cortex.
Almost none returning to primary motor cortex.
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38. Caudate circuit
Important for cognitive functions
Thinking process of brain
Thoughts generated in brain
Motor action occurs
When we saw a lion if basal ganglia is intact, immediately we will turn away
from lion, run and even climb a tree
If basal ganglia are damaged the individual will takes longer and longer time
to think what to do………Lion will do by that time
39. Timing and scale the intensity of movements
To control movements two important capabilities of brain are
1. Determine how rapidly the movement is performed
2. Control how large the movement will be
We can write letter “a” slowly and rapidly
We can also write small a on paper and large A on the blackboard
The proportional characteristics of the letter remains same
40. Timing and scale the intensity of movements
In patients with basal ganglia lesion, these timing and scaling of
movements is almost absent
Basal ganglia functions in close association with cerebral cortex.
One important area is posterior parietal cortex
Lesion of posterior parietal cortex causes agnosia (inability to
recognize the objects or persons)
41. Timing and scale the intensity of movements
Patient with right parietal cortex lesion try to copy drawings
Ability to copy left side of drawing is severely impaired
Such a person also avoid using his left side arm, hand or other
portions of his left side body for performance of task or washing
this side of the body ( personal neglect syndrome)
He lost sense that side body exists
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43. Functions of specific neurotransmitters
Dopamine pathway from substantia nigra to striatum
GABA pathway from striatum to substantia nigra
Ach pathway from cortex to striatum
Multiple general pathways from brian stem secrete norepinephrine,
serotonin, enkephalins and other N.T
Multiple glutamate pathways that provides most of excitatory signals
balances inhibitory signals by dopamine, GABA, serotonin pathways
44. Parkinson’s disease
Paralysis agitans
Hypokinetic and hyperkinetic features
Described by James Parkinson
Destruction of substantia nigra portion (pars compacta)
This portion sends dopaminergic neurons to the striatum
Damage of nigrostriatal pathway
45. Parkinson’s disease
First disease identified as being due to a deficiency in a specific
neurotransmitter
Estimated to occur in 1-2% of individuals over the age of 65
Hypokinetic – Akinesia, bradykinesia
Hyperkinetic- resting tremor, cogwheel rigidity
There is a decrease in normal, unconscious movements such as
swinging arms during walking
47. Parkinson’s disease
Rigidity of much of the musculature of the body
Mask-like face – No facial expressions
Involuntary tremors of involved areas even when the person is resting ( resting tremors)
Akinesia – serious difficulty in initiating a movement
Bradykinesia- slowness of movements
Postural instability caused by impaired postural reflexes leading to poor balance and falls
Dysphagia – difficulty in swallowing
Speech disorders
Gait disturbances
Fatigue
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49. Parkinson’s disease
The cause of these abnormal motor effects is unknown
Dopamine is an inhibitory N.T
Damage to the nigrostriatal pathway causes the striatum to be overly
active
Continuous output of excitatory signals to the corticospinal motor
system
Overly excite many muscles - rigidity
50. Parkinson’s disease
The cause of these abnormal motor effects is unknown
Dopamine is an inhibitory N.T
Damage to the nigrostriatal pathway causes the striatum to be overly
active
Continuous output of excitatory signals to the corticospinal motor
system
Overly excite many muscles - rigidity
51. Parkinson’s disease – non motor symptoms
Most notably depression
hyposmia or rapid eye movement sleep behavior disorder (RBD)
Constipation
Autonomic disorders
Cognitive dysfunction
Screening these early non-motor features might be one approach
towards early 'preclinical' diagnosis of PD.
52. Parkinson’s disease - Treatment
Administration of L-Dopa ameliorates many symptoms
Especially rigidity and akinesia
L-Dopa is converted to dopamine in brain and restore normal
balance between the N.T
Administration of dopamine has not produce similar effect
because dopamine can not cross BBB
53. Parkinson’s disease - Treatment
Administration of L-deprenyl
Inhibits monoamino oxidase
Responsible for destruction of dopamine secreted
So dopamine remains longer time in basal ganglia
A combination of L-dopa and L-deprenyl is more helpful
treatment
54. Parkinson’s disease - Treatment
Surgical treatment by making lesions in globus pallidus
(pallidotomy) or in subthalamic nucleus helps to restore the
output balance towards normal
Implant dopamine-secreting tissues in or near basal ganglia
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HOME ARCHIVES VOL 10 NO 3 (2019 ):VOLUME 10 ISSUE 3 Original Articles
Effect of caloric vestibular stimulation in a paraquat-induced
parkinsonian mouse model
Sai Sailesh Kumar Coothy
Assistant Professor & HOD, Department of Physiology, Vishnu Dental
College, Bhimavaram, West Godavari District-AndhraPradesh, India
Srilatha Coothy
Assistant Professor, Department of Biochemistry, Vishnu Dental College,
Bhimavaram, West Godavari District-AndhraPradesh.India
DOI:h tt p s://d oi.org/10.26452/ijrp s.vl0 i3.1
430
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57. HOME ABOUT • ISSUES • JOURNAL POLICIES • USERFUL INFO • CONTACT US
HOME ARCHIVES VOL10 NO 1 (2019}:VOLUME 10 ISSUE1 Original Articles
Effect of caloric vestibular stimulation on brain
neurotransmitters in an MPTP-induced mouse model of
Parkinson's disease
Kumar Sai Sailesh
Department of Physiology, Vishnu Dental College, Bhimavaram, West
Godavari District, Andhra Pradesh, India
Archana R
Department of Physiology, Saveetha Medical College, Saveetha Institute of
Medical and Technical Sciences, Thandalam , Chennai, Tamil Nadu, India
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69. Huntington’s disease (Huntington’s chorea)
Autosomal dominant hereditary disorder
Symptoms start at 30- 40 years
Starts with flicking movements in individual muscles
Then progressive severe distortional movements in entire body
Severe dementia develops along with motor dysfunctions
70. Huntington’s disease (Huntington’s chorea)
Damage of strionigral pathway
Loss of cell bodies of GABA secreting neurons
GABA pathway inhibits substantia nigra and GP
Loss of inhibition leads to outburst of signals from SN and GP
Cause distortional movements
71. Huntington’s disease (Huntington’s chorea)
Dementia may not be due to loss of GABAergic neurons
It may be due to loss of Ach secreting neurons especially in the
thinking areas of cortex
The abnormal gene that cause disease has been found
The abnormal protein cause the disease is Huntington
How this protein cause disease is not known
72. A 69-year-old man went to consult his physician. He had tremors in his
hands and fingers. His face was inexpressive. When he was invited to
enter the physician’s office, he had difficulty standing up. He walked
slowly into the office. There was no sensory loss. The stretch reflex was
normal. Muscles exhibited rigidity.
73. 1. Identify this condition
2. Discuss the physiological basis of this condition
3. Describe the connections of basal ganglia
4. Discuss the functions of basal ganglia