RESUMO
O Tronco encefálico (TE) é uma estrutura singular do sistema nervoso central, pois nele passam tratos sensoriais ascendentes da medula espinal, tratos sensoriais da cabeça e do pescoço, os tratos descendentes motores originados no prosencéfalo (divisão mais rostral do encéfalo), e as vias ligadas aos centros de movimento dos olhos. Contém ainda os núcleos dos nervos cranianos e está envolvido na regulação do nível de consciência através de projeções ao prosencéfalo oriundas da formação reticular. Todas essas estruturas coexistem em um espaço muito exíguo, o que faz com que o TE seja um local muito sensível às alterações patológicas, sendo que os pacientes apresentam muitos sinais neurológicos mesmo com lesões muito pequenas nesse local. Compreender a anatomia interna do TE é essencial para o diagnóstico neurológico e a prática da medicina clínica. Outros profissionais da saúde também se beneficiam desse conhecimento para melhor manejo dos seus pacientes neurológicos. Essa revisão apresenta detalhes da anatomia macroscópica e microscópica do bulbo, bem como seus correlatos clínicos frente às lesões mais comuns dessa divisão particular do TE, conhecidas como síndromes bulbares.
The brainstem is a unique structure in the central nervous system, since it gives way to ascending sensory tracts from the spinal cord, sensory tracts from the head and neck, motor descending tracts originating from the forebrain, and the pathways connected to the eye movement centers. It also contains the cranial nerve nuclei and is involved in the regulation of consciousness levels through projections to the forebrain originating in the reticular formation. All these structures coexist in a very small space, which makes the brainstem very sensitive to pathological changes, with patients presenting several neurological symptoms even with very small brainstem lesions. Understanding the internal anatomy of the brainstem is essential for neurological diagnosis and the practice of clinical medicine. Other health professionals also benefit from this knowledge to better manage their neurological patients. This review presents detailed information on the macroscopic and microscopic anatomy of the medulla, as well as its clinical correlates in the face of the most common lesions of this particular division of the brainstem, known as medullary syndromes.
Assuntos
Humanos , Síndrome Medular Lateral/diagnóstico , Bulbo/anatomia & histologia , Tratos Piramidais/anatomia & histologia , Formação Reticular/anatomia & histologia , Núcleo Espinal do Trigêmeo/anatomia & histologia , Área Postrema/anatomia & histologia , Pedúnculo Cerebral/anatomia & histologiaRESUMO
RESUMEN: La neuroanatomía y la neurofisiología han permitido en gran parte entender de forma más integrada las estructuras que conforman el sistema nervioso y los mecanismos asociados con la transmisión de los potenciales de acción, relacionados con la vía corticoespinal en la ejecución de movimientos voluntarios. Se realizó una revisión histórica sobre la vía corticoespinal, desde el punto de vista neuroanatómico y neurofisiológico mediante una revisión de literatura en distintas bases de datos y libros de texto dedicados a estas vías nerviosas. La información obtenida se ordenó cronológicamente, seleccionando los datos más relevantes que desde el punto de vista neuroanatómico y neurofisiológico han permitido comprender su mecanismo funcional. Actualmente se tiene un conocimiento muy depurado de los distintos elementos que componen la vía corticoespinal, lo que permitirá su aplicación en el campo de la salud y resolver múltiples problemas de la función motora.
SUMMARY: Neuroanatomy and Neurophysiology have, in large part, permitted a more thorough understanding of those structures that conform the nervous system and mechanisms associated with the transmission of action potentials associated with the corticospinal tract. This assertion is made based upon a literature review of various databases and textbooks dedicated to said nerve tracts. The information obtained was ordered chronologically, and data was selected that, from the neuroanatomical and neurophysiological viewpoints, were most relevant and have permitted the comprehension of its functional mechanism. The thorough understanding of those elements that compose the corticospinal tract will permit its application in the health field and resolve multiple motor function problems.
Assuntos
Humanos , História Antiga , História do Século XVII , História do Século XVIII , História do Século XIX , História do Século XX , Tratos Piramidais/anatomia & histologia , Tratos Piramidais/fisiologia , Neuroanatomia/história , Neurofisiologia/históriaRESUMO
The descending corticospinal (CS) projection has been considered a key element for motor control, which results from direct and indirect modulation of spinal cord pre-motor interneurons in the intermediate gray matter of the spinal cord, which, in turn, influences motoneurons in the ventral horn. The CS tract (CST) is also involved in a selective and complex modulation of sensory information in the dorsal horn. However, little is known about the spinal network engaged by the CST and the organization of CS projections that may encode different cortical outputs to the spinal cord. This study addresses the issue of whether the CS system exerts parallel control on different spinal networks, which together participate in sensorimotor integration. Here, we show that in the adult rat, two different and partially intermingled CS neurons in the sensorimotor cortex activate, with different time latencies, distinct spinal cord neurons located in the dorsal horn and intermediate zone of the same segment. The fact that different populations of CS neurons project in a segregated manner suggests that CST is composed of subsystems controlling different spinal cord circuits that modulate motor outputs and sensory inputs in a coordinated manner.
Assuntos
Córtex Cerebral/fisiologia , Potenciais Evocados/fisiologia , Tratos Piramidais/anatomia & histologia , Tratos Piramidais/fisiologia , Medula Espinal/fisiologia , Potenciais de Ação/fisiologia , Animais , Mapeamento Encefálico , Córtex Cerebral/citologia , Estimulação Elétrica , Masculino , Neurônios/fisiologia , Ratos , Ratos Wistar , Tempo de Reação , Medula Espinal/citologiaRESUMO
Hallucinations can be auditory, visual, tactile, gustatory, or olfactory, and can be caused by psychiatric (such as schizophrenia and depression), neurological (such as cerebrovascular accidents, neoplasia, and infection), or endocrine and metabolic disorders. Musical hallucinations related to neurological disorders are rare. The authors present a case of a patient with a right insular glioma who developed transient musical hallucinations after microsurgical resection of the tumor.