The Human Brain : From Neurone to Nervous System

STRUCTURE OF THE THALAMUS; SOMATOSENSORY and MOTOR NUCLEI


  1. The Thalamus is about the size of a walnut, situated in the centre of the brain, and divided into two halves, one on either size of the third ventricle. The internal capsule, which contains axons connecting the cortex with other parts of the CNS, including the motoneurones, separates the thalamus from the basal ganglia.

  2. The Thalamic nuclei include relay stations in all the major sensory pathways; somatosensory modalities use separate nuclei within the ventrobasal and posterior thalamus.

  3. Other nuclei, concerned with motor control, provide feedback to the cortex from the cerebellum and basal ganglia.

  4. The thalamus consists of many nuclei with different specific functions, separated from each other by bands of axons called laminae. Each side of the thalamus is concerned with sensory information from the contralateral side of the body, and objects in the contralateral visual and auditory fields.

  5. The thalamus is surrounded by a thin layer of non-specific nuclei, known as the Reticular Nucleus of the thalamus, which is concerned with regulating the overall activity of the cerebral cortex, and plays a role in the sleep/waking cycle.

  6. Key Words: Thalamic nuclei and connections; sensory and motor functions of the thalamus; Reticular Nucleus of the Thalamus.







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