Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2r centres are involved in extrapyramidal feedback, namely the olivary nucleus, the cerebellum and the thalamus.14.1.1Olivary NucleusThe olivary nucleus is an intermediate station on the pathway from the higher extrapyramidal command centres to the cerebellum (Figure 14.1). It corresponds to the pont Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2ine nuclei in the pyramidal feedback circuit (Figure 12-2). The site of the olivary nucleus in the medulla oblongata is shown schematically in FigureEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
8.3 (see also Figure 22.7).MidlineLevel of foramen magnumFigure 14.1 Diagram of the feedback circuits of the extrapyramidal system, rhe motor centres 14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2from the cerebellum, rhe globus pall idus is the focal point of, and in this diagram represents, the basal nuclei. The globus pallidus has a feedback circuit through the thalamus and cerebral cortex, which enables the basal nuclei to collaborate with the cerebral cortex, n. = nucleus; nn. = nuclei; Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2m.r.c. = motor reticular centre; and r.f. = reticular formation.Cerebellar cortex14.1.2CerebellumTwo components of the cerebellum, i.e. the cerebellarEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
cortex and the cerebellar nuclei (such as the dentate nucleus), are involved in extrapyramidal feedback circuits. Note the similarity to the pyramida14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2ack circuits which return to the forebrain. The ventral group of thalamic nuclei controls all thalamic feedback circuits.Strictly, it is the ventrolateral thalamic nucleus, as in the pyramidal feedback circuits (Figure 12.2) (see Section 18.17).14.2Feedback CircuitsAll of the nine motor ‘command cen Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2tres’ of the extrapyramidal system together with the pyramidal system have feedback circuits through the cerebellum (see Section 12.2). The function oEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
f these extrapyramidal feedback pathways is to inform the cerebellum of the intended motor actions of the extrapyramidal motor centres and enable the 14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2 (basal ganglia), has a shorter feedback circuit directly through the thalamus to the cerebral cortex. This feedback circuit enables the basal nuclei to carry out their main role, namely collaboration with the cerebral cortex via the thalamus (see Section 13.3).The cerebellar feedback circuits of th Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2e nine extrapyramidal motor command centres (Nos. 1 to 9) are as follows:14.2.1Centres 1 and 2: The Cerebral Cortex and Globus PallidusThe feedback paEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
thways to the command centres 1 and 2 are similar, projecting (in sequence) to the olivary nucleus, to the cerebellar cortex, to a cerebellar nucleus,14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2r way to the cerebellar cortex, and then decussate again on the way back. The circuit for the globus pallidus is finally completed by projections from the cerebral cortex back to the globus pallidus (Figure 14.1).These pathways enter the cerebellum through the caudal cerebellar peduncle, and exit th Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2rough the rostral peduncle (see Sections 16.3 and 16,5). The relay in the thalamus takes place in the ventral group of thalamic nuclei (in the ventrolEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
ateral nucleus, see SeciionliU?).14.2.2Centres 3 and 4: The Midbrain Reticular Formation and Red NucleusAgain these feedback circuits project first to14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2leus (Figure 14.1). As before, they also decussate twice, i.e. on the way in and the way out of the cerebellum.Entrance to the cerebellum is gained through the caudal peduncle, and the outlet is via the rostral cerebellar peduncle, as for Centres 1 and 2.14.2.3Centres 5 and 9: The Tectum and Vestibu Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2lar NucleiCentres 5 and 9 are the extrapyramidal motor centres that are associated with information from the special senses. Their feedback pathways mEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
iss out the olivary nucleus, projecting via the caudal cerebellar peduncle directly to the cerebellar cortex. They receive return pathways from a cere14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2ck pathways of the extrapyramidal centres; i.e. the left vestibular nuclei project to, and receive return projections from, the left side of the cerebellum. Correlate this with the fact that the vestibulospinal tract does not decussate (see Section 9.3).The tectal pathways to and from the cerebellum Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2 pass through the rostral cerebellar peduncle; the afferent and efferent vestibular pathways use the caudal cerebellar peduncle (see Sections 16.3 andEbook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2
16,5).14.2.4Centres 6, 7 and 8: The Pontine Motor Reticular Centres the Lateral Medullary Motor Reticular Centres and the Medial Medullary Motor Reti14Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree major Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 2s via a cerebellar nucleus (Figure 14.1).All of these pathways from the hindbrain command centres of the reticular formation to the cerebellum travel in the caudal cerebellar peduncle (see .Section Ebook King’s applied anatomy of the central nervous system of domestic mammals (2/E): Part 214Extrapyramidal Feedback and Upper MotorNeuron DisordersFeedback of the Extrapyramidal System14.1Neuronal Centres of the Feedback CircuitsThree majorGọi ngay
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