2-Minute Neuroscience: Touch and the Dorsal Columns-Medial Lemniscus
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  • Release Date: 2024-05-11
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  • sensations
  • neurons
  • CNS
  • sensory pathway
Video Introduction

Somatosensation involves sensations from the body. When these sensations come from the external environment, they are picked up by receptors in the skin called cutaneous receptors. There are several different types of cutaneous receptors, each designed to respond to specific types of touch sensations like pressure, pain, or vibration. 

The main pathway that carries information about touch to the brain is the dorsal columns-medial lemniscus (also called the posterior columns-medial lemniscus). This pathway also carries information about proprioception, or the position of the body in space; these signals come from proprioceptors in muscles and joints. Fibers in the dorsal columns-medial lemniscus leave cutaneous receptors or proprioceptors and enter the spinal cord via the dorsal roots. They travel up the spinal cord to the medulla in one of two fiber bundles within the dorsal columns: the fasciculus gracilis, which carries information from the lower half of the body, or the fasciculus cuneatus, which carries information from the upper limbs and torso. In the medulla, the fasciculus gracilis and fasciculus cuneatus synapse on the next neurons in the pathway in areas called the nucleus gracilis and the nucleus cuneatus, respectively. It is from these nuclei that the second part of the pathway arises: a fiber bundle called the medial lemniscus. The medial lemniscus leaves the dorsal column nuclei and quickly decussates, or crosses over to the other side of the brain, before traveling up to the thalamus, where it synapses in a part of the thalamus called the ventral posterolateral nucleus, or VPL.

A third part of the pathway arises from the thalamus and travels up to an area of the cortex called the postcentral gyrus, which contains the main sensory area for touch in the brain: the somatosensory cortex. Specific parts of the somatosensory cortex receive signals from specific areas of the body, an arrangement that is known somatotopic. Information about the nature and location of the sensation are integrated in the somatosensory cortex, where the conscious perception of the sensation begins. [1]

References
  1. Nolte J. The Human Brain: An Introduction to its Functional Anatomy. 6th ed. Philadelphia, PA. Elsevier; 2009.
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Challenged, N. 2-Minute Neuroscience: Touch and the Dorsal Columns-Medial Lemniscus. Encyclopedia. Available online: https://encyclopedia.pub/video/video_detail/1236 (accessed on 25 May 2024).
Challenged N. 2-Minute Neuroscience: Touch and the Dorsal Columns-Medial Lemniscus. Encyclopedia. Available at: https://encyclopedia.pub/video/video_detail/1236. Accessed May 25, 2024.
Challenged, Neuroscientifically. "2-Minute Neuroscience: Touch and the Dorsal Columns-Medial Lemniscus" Encyclopedia, https://encyclopedia.pub/video/video_detail/1236 (accessed May 25, 2024).
Challenged, N. (2024, May 11). 2-Minute Neuroscience: Touch and the Dorsal Columns-Medial Lemniscus. In Encyclopedia. https://encyclopedia.pub/video/video_detail/1236
Challenged, Neuroscientifically. "2-Minute Neuroscience: Touch and the Dorsal Columns-Medial Lemniscus." Encyclopedia. Web. 11 May, 2024.
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