Download BASAL GANGLIA: A "pit stop" that integrates the movement

BASAL GANGLIA: A "pit stop" that integrates the
movement, cognition and emotion.
Poster No.:
C-0795
Congress:
ECR 2011
Type:
Educational Exhibit
Authors:
V. M. González Montaño , T. M. Zamorano Pozo , R. Querol
1
1
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2
1
Pascual , J. Alvarez Linera , R. Palacios , M. Á. FERNÁNDEZ
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GIL ; Badajoz/ES, Madrid/ES, Badajoz, Ba/ES
Keywords:
Neuroradiology brain, MR, MR-Functional imaging, Education,
Motility, Dementia
DOI:
10.1594/ecr2011/C-0795
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Learning objectives
The basal ganglia are a collection of nuclei whose main function is to intervene in the
control of motor actions. Our intention is...
- To explain the anatomy of this area of the Central nervous system.
- We will use this schemes as well as MRI images that allow us to better understand
this region.
Background
The basal ganglia are a group of subcortical nuclei, located in the centre of the Central
Nervous System.
They have numerous connections between themselves and with other structures.
Knowledge of these connections help us to better understand their different functions.
They are involved in the motion control. But not only influence on the movements, also
play an important role in cognition and emotion.
Any alteration on them is related to motor impairment, as well as psychiatric and memory
disorders.
COMPONENTS OF THE BASAL GANGLIA
Basal ganglia are composed by:
• N. Accumbens
• N. Caudate
• Putamen
• Globus Pallidus: 1. External segment 2. Internal segment
• Subthalamic nucleus
• Substantia Nigra: 1. Pars compacta 2. Pars reticulata
The nucleus accumbens, the n. caudate and putamen have a common embryological
origin, similar histological features and similar connections. These three form the
Striatum.
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The putamen and globus pallidus, in turn, form the Lenticular nucleus.
The striatum and the globus pallidus are the fundamental components of the basal
ganglia.
LENTICULAR NUCLEUS:
It has a wedge shaped.
The putamen (" shell " in Latin) is located in the outer portion of the lenticular nucleus
and is in contact with the insula. Located in the border region between diencephalon
and telencephalon. It is separated from the outer portion of G. Pallidus by the Lateral
Medullary Lamina.
The globus pallidus is divided into two parts by the Internal Medullary Lamina: External
segment and Internal segment.
Figure 1.
Figure 2.
Figure 3.
CAUDATE:
The Caudate rests on the lateral ventricular wall and acquires with him a form as a "C".
It has 3 parts:
- Head: frontal horn located adjacent to the lateral ventricle.
- Body: lateral wall of the lateral ventricles.
- Tail: it borders with the inferior horn.
Figure 4.
Figure 5.
INTERNAL CAPSULE:
Set of axons that come and go to the cerebral cortex.
It separates the striatum into three components.
It also separates the inner segment of g. pallidus and the pars reticulata of the substantia
nigra.
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EXTERNAL CAPSULE:
White matter that contains association fibers cortico-subcortical .
It separates the putamen from the insular cortex.
Inside we see a thin band of neurons called Claustrum, that has interconnections with
the cerebral cortex.
Figure 6.
Figure 7.
N. ACCUMBENS:
Nuclear structure located in the ventral striatum.
The most anterior region of N. accumbens, n. caudate, putamen and ventral striatum
form a part of the limbic system.
Figure 8.
SUBTHALAMIC NUCLEUS:
It has a convex lens shape.
It is surrounded by white matter and located between the cerebral peduncle and
thalamus.
Figure 9.
SUBSTANTIA NIGRA:
It is composed by 2 parts:
- Pars Compacta, that is composed of pigmented neurons "packed". They issue
dopaminergic and modulating projections to other parts of the basal ganglia.
Pars Reticulata, that is near to the brainstem. It contains a smaller number of neurons,
mostly nonpigmented. It is one of the core issuers GB.
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Figure 9.
CIRCUITS OF THE BASAL GANGLIA:
The nuclei of the basal ganglia may be divided into three groups, depending on their
connections:
- INPUT NUCLEI: They receive different projections of the rest of the basal ganglia. In
turn, they emit projections to the input nuclei and to the intrinsic nuclei.
- Caudate
- Putamen
- Accumbens
- OUTPUT NUCLEI: They project to regions of the diencephalon and brainstem that are
not part of the basal ganglia.
- G. Pallidus (internal segment)
- Ventral pallidum
- S. Nigra (Pars reticulata)
- INTRINSIC NUCLEI: The connections are restricted to the components of the basal
ganglia.
- G. Pallidus (external segment)
- Subthalamic N.
- S. Nigra (Pars compacta)
- Ventral tegmental area
Most of the inputs come through the striatum .
The outputs make it through the external segment of G. Pallidus.
There is a excitatory complex and inhibitory complex in the basal ganglia, mediated by
many neurotransmitters.
All these connections involve a variety of functions:
General motor control.
Eye movements.
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Cognitive functions.
Emotional functions.
We can see the main inputs in the figure number 10 and the main outputs in the figure 11.
Figure 12.
We can identify four channels through the basal ganglia.
1. Motor channel. Figure 13.
2. Oculomotor channel. Figure 14.
3. Prefrontal channel. Figure 15.
4. Limbic channel. Figure 16.
We can see the intrinsic circuit of the basal ganglia in the figure 17.
Images for this section:
Fig. 1
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Fig. 2
Fig. 3
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Fig. 4
Fig. 5
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Fig. 6
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Fig. 7
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Fig. 8
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Fig. 9
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Fig. 10
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Fig. 11
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Fig. 12
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Fig. 13
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Fig. 14
Fig. 15
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Fig. 16
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Fig. 17
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Imaging findings OR Procedure details
We have anted to clarify the anatomy and connections of the BG, reviewing the neuractive
agents and the routs which connect each other and other pathways, using simple and
elemental drawings and conventional MRI.
Conclusion
- The alteration of the basal ganglia are related with motion control deficits , since the
tremor to the rigidity of Parkinson's, as well as Huntington's movements.
- In addition, the pathology of the basal ganglia are also accompanied by impaired
intellectual ability, suggesting their involvement in cognition and memory.
This core group is also involved in diseases related to drug addiction and various
psychiatric disorders.
- Anatomical knowledge of this area is essential for proper radiologic evaluation of it,
which will help us to understand the relationship of radiation-clinical alterations.
Personal Information
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