1. Basal ganglia

2. Basal ganglia Basal ganglia regulate
muscle contraction
muscle force
multijoint movement
Sequencing of movement
The output of the basal ganglia is via
Motor area of the cerebral cortex
Pendunculopontine nucleus (elicits rhythmical behaviors such as locomotor patterns) : located in the brain stem

4. Caudate
Putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra

7. Corpus straitum straitum Caudate nucleus putamen Leniform nucleus
Globus pallidus
The function of caudate : cognitive, not motor
The function of the ventral striatum : limbic
Basal ganglia : no direct connections with
lower motor neurons
(1) Motor planning areas of the cerebral cortex
(2) Pedunculopontine nucleus of the midbrain

8. Subthalmic nucleus : inferior to the thalamus and lateral to the hypothalamus
Substantia nigra : a nucleus in the midbrain named for the color of its cells
Compacta (provide essential dopamine to the striatum)
Reticularis
Substantia nigra reticularis and globus palidus internus : output nuclei of the basal ganglia system
Output nuclei : inhibit the motor thalamus and the pedunclopontine nucleus of the midbrain

9. (1) Motor planning areas of the cerebral cortex
a major basal ganglia circuit connects motor and somatosensory areas of the cerebral cortex-> the putamen-> the output nuclei-> the motor thalamus-> motor areas of the cerebral cortex ; corticofugal tracts
(2) Pedunculopontine nucleus of the midbrain
From the globus pallidus internus to the pedunclopontine nucleus, thence to the reticulospinal and to the vestibulospinal tracts

12. Basal Ganglia Connections
Input Portion
STRIATUM
(Caudate Nucleus and Putamen)
Output Portion
1. PALLIDUM (Globus Pallidus)
2. SNr (Substantia Nigra, Pars Reticulata)

13. Basal Ganglia Connections
STRIATUM
Afferents from
1. Cerebral Cortex [Corticostriatal Projection]
2. Thalamus [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

14. Afferent Connections of Basal Ganglia

15. Input-Output Relationship of Basal Ganglia 1. striopallidal fiber
2. strionigral fiber
3. strionigral fiber
from striosome
to SNc
4. ventrostrio-
ventro-pallidal fiber

16. 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]
1. Thalamus (VLm, VAmc, MD) [Nigrothalamic Projection]
2. Brain Stem Nucleus: Tectum (Superior Colliculus) &
Pedunculopontine Nucleus (PPN)

17. Efferent Connections of Basal Ganglia

18. Connections of the Basal Ganglia Pallidum SNr
Cerebral
Cortex
amygdaloid body
raphe
STRIATUM
Thalamus
STN
SNc
Pallidum
SNr
habenular
nucleus
PPN
(pedunculopontine nucleus)
tectum
(superior colliculus)

19. Basal Ganglia (Main Motor Circuit) Connections
Primary
Motor Area
(M I)
Supplementary
Motor Area
(SMA)
STRIATUM
(Putamen)
pyramidal
tract
ansa
lenticularis
THALAMUS
(VLo, VApc, CM)
PALLIDUM
(GPi)
lenticular
fasciculus
LMN

20. SNr Basal Ganglia (Prefronatal Complex Loop) Connections Primary
Motor Area
(M I)
Prefrontal
Association
Cortex
STRIATUM
(Caudate
Nucleus)
pyramidal
tract
THALAMUS
(VLm, VAmc, MD)
SNr
(Substantia Nigra,
pars reticulata)
LMN

21. Anterior Cingulate Gyrus Hippocampal Formation
Basal Ganglia (Limbic Loop) Connections
Orbitofrontal Cortex
Anterior Cingulate Gyrus
Hippocampal Formation
Ventral Striatum
Caudate Nucleus
THALAMUS
(VAmc, MD)
Ventral Pallidum
GPi, SNr

22. SNr Basal Ganglia (Oculomotor Loop) Connections Primary Motor Area
(M I)
Frontal
Eye Field
(area 8)
STRIATUM
(Caudate
Nucleus)
pyramidal
tract
SNr
(Substantia Nigra,
pars reticulata)
THALAMUS
(VLm, VAmc, MD)
LMN
Tectum

23. Basal Ganglia and Pyramidal Tract (supplementary motor area)
SMA
(supplementary motor area)
upper motor neuron
UMN
pyramidal
tract
BASAL
GANGLIA
CIRCUIT
lower motor neuron
LMN

24. Function of the basal ganglia
Sequencing movements and regulating muscle tone and muscle force
Select and inhibit specific motor synergies;
- from putamen to the output nuclei : select synergies (direct path)
- via the globus pallidus externus and subthalamic nucleus : inhibit synergies (indirect path)

25. Pathology of the basal ganglia
Movement disorders
- hypokinetic disorders
parkinson’s disease
- hyperkinetic disorders
Huntington’s disease
Dystonia
Subtype of cerebral palsy
Difference in abnormal movements are due to dysfunction in specific parts of the basal ganglia-thalamocortical motor circuit and in the basal ganglia-pedunculopontine nucleus
The basal ganglia inhibit the motor thalamus and the pedunculopontine
Excessive inhibition : hypokinetic disorder
Inadequate inhibition : hyperkinetic disorders

26. Parkinson’s disease:
Muscular rigidity
Shuffling gait
Drooping posture
Rhythmical muscular tremors
Masklike facial expression
Parkinson’s disease interferes with both voluntary and automatic movements
Pathology : the cause of cell death is unknown
- the death of dopamine-producing cells in the substantia nigra compacta and acetylcholine-producing cells in the pedunculopontine nucleus

27. The loss of dopamine in the basal ganglia direct pathway : reduces activity in the motor areas of the cerebral cortex, decreasing voluntary movements
The loss of pedunculopontine cells, combined with increased inhibition of the pedunculopontine nucleus : disinhibits the reticulospinal and vestibulospinal tracts, producing excessive contraction of postural muscles
People with parkinson’s disease : difficulty coming to standing from sitting, flexed posture, shuffling of the feet, decreased or absent arm swing

30. Signs of parkinson’s disease
Rigidity : increased resistance to movement in all muscles; causes active muscle contraction, directly
Hypokinesia : decreased ranges of active motion and in the lack of automatic movements, including facial expression and normal arm swing during walking, decreased ability to control the force output of muscles
Resting tremor : pill-rolling tremor; tremor is prominent when the hand is at rest and diminishes during voluntary movement
Freezing during movement : when their movements abruptly cease (interrupts gait)
Visuoperceptive impairments : deficit in using visual information to guide movements (ex: a walker)

31. Parkinson’s dementia :
Postural instability : secondary to the extreme stiffness of postural flexor and extensor.
Parkinson’s dementia :
Autonomic dysfunction
Interfere with the ability to plan, to maintain goal orientation, and to make decision.

32. Dopamine (L-dopa) : initially effective in reducing signs of the disease
However, tolerance to L-dopa, side effects (hallucinations, delusions, psychosis, dyskinesia) and progression of the disease with involvement of other cells
Disknesia : involuntary movements
- chorea: brisk, jerky movements
- dystonia : involuntary sustained postures or repetitive movements
Surgical procedure
Physical and occupational therapy : improve movement and functional abilities ; moderate level of activity

36. parkinsonism
Collective name for disorders that cause signs similar to parkinson’s disease
disorders that cause the signs seen in parkinson’s disease and encompasses disorders of toxic, infectious, or traumatic etiology
Lesions of the lentiform nucleus are associated with parkinsonism
Side effect of drugs that treat psychosis or digestive problems
Phenothiazine, thioxanthine, antiemetics and other drugs that block CNS dopamine receptor

37. Multiple system atrophy
Multiple system atrophy(MSA) :
progressive degenerative disease affecting the basal ganglia, cerebellar, and autonomic systems and cerebral cortex
MSA is characterized by;
Parkinsonism
Cerebellar signs
Autonomic dysfunction

38. Parkinsonism : slow movements and rigidity
Cerebellar aspects : dysarthria (uncoordinated speech), truncal and gait ataxia (narrow-based)
Autonomic aspects : postural hypotension, bladder and bowel incontinence, abnormal respiration, decreased sweating, tears, saliva, impotence in men
A decrease in goal-oriented cognitive ability and difficulty with directing attention
In men : usually impotence
In women : difficulty urinating

39. Diagnosis
Pure parkinsonism : if no autonomic or cerebellar signs are present
Pure autonomic failure : orthostatic hypotension and other autonomic signs occur without signs of basal ganglia or cerebellar involvement
- affects postganglionic neurons of the sympathetic system
- MSA : both the preganglionic and postganglionic neurons in the sympathetic and parasympathetic systems
In MSA : autonomic neurons :
- lost from brain stem nuclei and from the spinal cord
- Parkinson’s disease is the most common misdiagnosis, and one third of people with MSA die while still misdiagnosed
- poor response to L-dopa, orthostatic hypotension, difficulty with urination, rapid progression of functional limitations, lou

40. MSA poor response to L-dopa orthostatic hypotension
difficulty with urination
rapid progression of functional limitations
Loud breathing
impotence

41. MSA is synonymous Treatment
Olivopontocerebellar atrophy : incoordination, dysarthria, balance deficits
Striatonigral degeneration : rigidity and bradykinesia
Shy-Drager syndrome : autonomic dysfunction
Treatment
drugs
Decrease orthostatic hypotension
- slow position changes
- avoiding prolonged standing
- eating smaller meals
- use of elastic garments
- avoidance of warm temperature
Exercise programs to maintain strength and physiologic fitness

42. Hyperkinetic Disorders
Abnormal involuntary movements
Huntington’s disease
Dystonia
Some type of cerebral palsy

43. Huntington’s disease Autosomal dominant hereditary disorder
Causes degeneration in many areas of the brain, most prominently in the striatum and cerebral cortex
Decrease in signals from the output nuclei, resulting in disinhibition of the motor thalamus and pedunculopontine nucleus -> disinhibition of the motor thalamus and pedunculopontine nucleus -> excessive output from the motor area of the cerebral cortex
Signs : chorea, consisting of involuntary, jerky, rapid movements, dementia
Onset : 40~ 50 age
Progressive, resulting in death about 15 years after signs first appear
Prevalence : 5~10 cases per 100,000 people

44. Dystonia Avoidance of heavy gripping of instruments Sensory retraining
Genetic, usually nonprogressive
Movement disorders : involuntary sustained muscle contractions causing abnormal postures or twisting, repetitive movements
Focal dystonias: limited to one part of the body (writer’s cramp, musician’s cramp) ; reduced reciprocal inhibition due to decreased descending inhibition
Treatment
Avoidance of heavy gripping of instruments
Sensory retraining
Mental rehearsal of the target movement without overt body movement
Motor control
Heat, cold and exercise
Medications : acetylcholine, GABA, dopamine
Surgical lesion of the motor thalamus or injection of botulinum toxin into the affected muscles
Segawa’s dystonia : interfere with walking and may mimic the appearance of cerebral palsy; progress slowly and can be effectively treated with medications

45. Choreoathetotic cerebral palsy
Abnormal involuntary movements
People with choreoathetosis, a type of cerebral palsy
Chorea : abrupt, jerky movements
Athetosis : slow, writhing, purposeless movements

46. summary Basal ganglia disorders
interfere with voluntary and automatic movements
Produce involuntary movements
Hypokinesia : decrease in the amount of and speed of voluntary and automatic movements (Parkinson’s disease)
Hyperkinesia : abnormal excessive movement (huntington’s disease, dystonia, choreoathetotic palsy)