The posterior column-medial lemniscus pathway (called the dorsal column in non-humans) is the sensory pathway responsible for transmitting discriminative sensation from the skin to the thalamus, and on to the cerebral cortex. Senses are the physiological methods of perception. ... Diagram of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system made up of a layer of tissues that protect underlying muscles and organs. ... MRI cross-section of human brain, with thalamus marked. ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ...

The name comes from the two structures that the sensation travels up: the posterior (or dorsal) columns of the spinal cord, and the medial lemniscus in the brainstem. Cross-section through cervical spinal cord. ... The medial lemniscus, also known as Reils band or Reils ribbon, is a pathway in the brainstem, that carries sensory information from the gracile and cuneate nuclei to the thalamus. ... The brain stem is the stalk of the brain below the cerebral hemispheres. ...

Journey of the posterior column-medial lemniscus pathway

Discriminative sensation is well developed in the fingers of humans, and allows us to feel fine textures and determine what an unknown object in our hands is without looking at it. Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are biologically classified as bipedal primates belonging to the mammalian species Homo sapiens (Latin for wise man or thinking man) under the family Hominidae (the great apes). ...

This fine sensation is detected by Meissner's corpuscles that lie in the dermis of the skin close to the epidermis. When these structures are stimulated by slight pressure, an action potential is started. Meissners corpuscles (discovered by the anatomist Georg Meissner (1829-1903) are a type of mechanoreceptor and more specifically, a tactile corpuscle(corpusculum tactus). ... The dermis is the layer of skin beneath the epidermis, that consists of connective tissue and cushions the body from stress and strain. ... Diagram of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system made up of a layer of tissues that protect underlying muscles and organs. ... Epidermis is the outermost layer of the skin. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ...

The action potential travels up an axon (the cell body of the neuron will be in a dorsal root ganglion). (The neurons are classified as unipolar, so they are regarded as having just one long process, an axon.) So the sensation travels from the skin, along the axon, past the neuronal cell body, and into the dorsal column of the spinal cord. An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Drawing by Santiago Ramón y Cajal of cells in the pigeon cerebellum. ... This is a dorsal root ganglion (DRG) from a chicken embryo (around stage of day 7) after incubation overnight in NGF growth medium stained with anti-neurofilament antibody. ...

The axons continue inside the spinal cord, running up the posterior (dorsal) column. Axons from the lower body are most medial (closer to the midline), and run in the gracile tract of the spinal column. Sensory axons from the upper body enter the spinal cord later, so are more lateral and travel up the cuneate tract.

At the brainstem

At the level of the closed medulla oblongata, these axons synapse with neurons in the gracile and cuneate nuclei. The secondary neurons (that start in the nuclei) cross over to the other side of the medulla (as internal arcuate fibres) to form the medial lemniscus. Position of medulla oblangata in the human brain The medulla oblongata is the lower portion of the brainstem. ... Illustration of the major elements in a prototypical synapse. ... The medial lemniscus, also known as Reils band or Reils ribbon, is a pathway in the brainstem, that carries sensory information from the gracile and cuneate nuclei to the thalamus. ...

At the medulla, the medial lemniscus is orientated perpendicular to the way the fibres travelled in the posterior columns. For example, in the columns, lower limb is medial, upper limb is more lateral. At the medial leminiscus, axons from the leg are more ventral, arm fibres more dorsal. Fibres from the trigeminal nerve (supplying the head) come in dorsal to the arm fibres, and travel up the lemniscus too. In humans, the lower limb is an anatomical term for the limb that is attached to the pelvic girlde, what is commonly referred to as the leg. ... In humans, the upper limb is an anatomical term for the limb that is attached to the pectoral girdle. ... The trigeminal nerve is the fifth (V) cranial nerve, and carries sensory information from most of the face, as well as motor supply to the muscles of mastication (the muscles enabling chewing), tensor tympani (in the middle ear) and other muscles in the floor of the mouth, such as the... For other uses of the word head, see head (disambiguation). ...

The medial lemniscus rotates 90 degrees at the pons. The secondary axons from neurons giving sensation to the head, stay at around the same place, while the leg axons move outwards. Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ...

The axons travel up the rest of the brainstem, and synapse at the thalamus (at the ventral posterolateral nucleus). Neurons starting in the thalamus travel up the posterior limb of the internal capsule, and again head and leg swap relative positions. The axons synapse in the primary sensory cortex, with lower body sensation most medial (e.g., the paracentral lobule) and upper body more lateral. MRI cross-section of human brain, with thalamus marked. ... The internal capsule is an area of white matter in the brain that separates the caudate nucleus and the thalamus from the lenticular nucleus. ... ...