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The medial lemniscus, also known as Reil's band or Reil's ribbon, is a large ascending bundle of heavily myelinated axons that decussate in the brain stem, specifically in the medulla. The medial lemniscus is formed by the crossings of internal arcuate fibers. The internal arcuate fibers are composed of axons of nucleus gracilis and nucleus cuneatus. The axons of the nucleus gracilis and nucleus cuneatus in the medial lemniscus have cell bodies that lie in the contralaterally. Lesion of the medial lemnisci causes an impairment of vibratory and touch-pressure sense. The medial lemniscus is part of the posterior column-medial lemniscus pathway, which ascends from the skin to the thalamus.〔Kamali A, Kramer LA, Butler IJ, Hasan KM. Diffusion tensor tractography of the somatosensory system in the human brainstem: initial findings using high isotropic spatial resolution at 3.0 T. Eur Radiol. 2009 19:1480-8. doi: 10.1007/s00330-009-1305-x.〕 ==Path== After neurons carrying proprioceptive or touch information synapse at the gracile and cuneate nuclei, axons from secondary neurons decussate at the level of the medulla and travel up the brainstem as the medial lemniscus on the contralateral (opposite) side. It is part of the posterior column-medial lemniscus pathway, which transmits touch, vibration sense, as well as the pathway for proprioception. The medial lemniscus carries axons from most of the body and synapses in the ventral posterolateral nucleus of the thalamus, at the level of the mamillary bodies. Sensory axons transmitting information from the head and neck via the trigeminal nerve synapse at the ventral posteromedial nucleus of the thalamus. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「medial lemniscus」の詳細全文を読む スポンサード リンク
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