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 1 2 1 Pascual, J. Alvarez Linera, R. Palacios, M. Á. FERNÁNDEZ 3 1 2 3 GIL ; Badajoz/ES, Madrid/ES, Badajoz, Ba/ES Keywords: Neuroradiology brain, MR, MR-Functional imaging, Education, Motility, Dementia DOI: 10.1594/ecr2011/C-0795 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 21
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. Page 2 of 21
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. Page 3 of 21
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. Page 4 of 21
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. Page 5 of 21
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 Page 6 of 21
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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 References - Sobotta. Atlas de Anatomía Humana. 20ª edición. Tomo 1. Cabeza, cuello y miembro superior. - Neuroanatomy through Clinical Cases. Hal Blumenfeld, M.D. - Neuroanatomy text and atlas. John H. Martin. Third edition. - The Human Brain. An introduction to its functional anatomy. John Nolte. Sixth edition. - Striatal volume loss in HD as measured by MRI and the influence of CAG repeat. H.D. Rosas, J. Godman, Y.I. Chen, B. G. Jenkins, D.N. Kennedy, M. Patti, l. J. Seidman, L.J. Seidman, M. F. Beal, W. J. Koroshetz. Neurology. - Huntington Disease: Volumetric, Diffusion-weighted, and Magnetization Transfer MR Imaging of Brain. Mario Mascalchi, Francesco Lolli, Riccardo Della Nave, Carlo Tessa, Page 20 of 21
Raffaele Petralli, Cinzia Gavazzi, Letterior S. Politi, Marco Macucci, Massimo Filippi, Silvia Piacentini.September 2004 Radiology, 232, 867-873 Page 21 of 21