7 Somatosensitivity, viscerosensititvity, proprioception and pain III Evolutionary point of view • The signals indicating potential damage are the most important and the corresponding systems evolved early – Pain – Temperature • The touch signals have adaptive value and evolved later http://www.slideshare.net/CsillaEgri/presentations http://www.slideshare.net/CsillaEgri/presentations Evolutionary point of view • The signals indicating potential damage are the most important and the corresponding systems evolved ealry – Pain – Temperature • The touch signals have adaptive value and evolved later http://www.slideshare.net/CsillaEgri/presentations http://www.slideshare.net/CsillaEgri/presentations Evolutionary point of view • The signals indicating potential damage are the most important and the corresponding systems evolved early – Pain – Temperature • The touch signals have adaptive value and evolved later • The structure of the receptor, nerve fibers and pathways reflects the evolution http://www.slideshare.net/CsillaEgri/presentations http://www.slideshare.net/CsillaEgri/presentations Somatosensory pathways • Three systems • (Archispinothalamic) – Interconnection of adjacent segments (tr. Spinospinalis) • Paleospinothalamic – tr. Spinoreticularis, tr. Spinotectalis… • Neospinothalamic – tr. Spinothalamicus • Dorsal column system – tr. Spinobulbaris Somatosensory pathways • Three systems • (Archispinothalamic) – Interconnection of adjacent segments (tr. Spinospinalis) • Paleospinothalamic – tr. Spinoreticularis, tr. Spinotectalis… • Neospinothalamic – tr. Spinothalamicus • Dorsal column system – tr. Spinobulbaris Somatosensory pathways • Paleospinothalamic – Low resolution – dull, diffuse pain („slow pain“) • Neospinothalamic – High resolution – sharp, localized pain („fast pain“), temperature – Low resolution – touch • Dorsal column system – High resolution – touch, proprioception Somatosensory pathways • Paleospinothalamic – Low resolution – dull, diffuse pain („slow pain“) • Neospinothalamic – High resolution – sharp, localized pain („fast pain“), temperature – Low resolution – touch • Dorsal column system – High resolution – touch, proprioception Somatosensory pathways http://neuroscience.uth.tmc.edu/s2/chapter02.html Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… • Evolved before neocortex Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… • Evolved before neocortex • The primary connection to the subcortical structures Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… • Evolved before neocortex • The primary connection to the subcortical structures • Basic defensive reactions and reflexes - vegetative response, reflex locomotion - opto-acoustic reflexes etc. Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… • Evolved before neocortex • The primary connection to the subcortical structures • Basic defensive reactions and reflexes - vegetative response, reflex locomotion - opto-acoustic reflexes etc. • Secondarily connected to cortex (after its evolution; tr. Spinoreticulo-thalamicus), but this system has a small resolutions – dull diffuse pain Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… • Evolved before neocortex • The primary connection to the subcortical structures • Basic defensive reactions and reflexes - vegetative response, reflex locomotion - opto-acoustic reflexes etc. • Secondarily connected to cortex (after its evolution; tr. Spinoreticulo-thalamicus), but this system has a small resolutions – dull diffuse pain • This tract is not designed for „such a powerful processor as neocortex“ Paleospinothalamic system • Tr. Spinoreticularis, spinotectalis… • Evolved before neocortex • The primary connection to the subcortical structures • Basic defensive reactions and reflexes - vegetative response, reflex locomotion - opto-acoustic reflexes etc. • Secondarily connected to cortex (after its evolution; tr. Spinoreticulo-thalamicus), but this system has a small resolutions – dull diffuse pain • This tract is not designed for „such a powerful processor as neocortex“ • Approximately half of the fibers cross the midline http://neuroscience.uth.tmc.edu Neospinothalamic system • Tr. Spinothalamicus Neospinothalamic system • Tr. Spinothalamicus • Younger structure primarily connected to neocortex • „High capacity/resolution“ Neospinothalamic system • Tr. Spinothalamicus • Younger structure primarily connected to neocortex • „High capacity/resolution“ • Detail information about pain stimuli (sharp, localized pain) • Information about temperature Neospinothalamic system • Tr. Spinothalamicus • Younger structure primarily connected to neocortex • „High capacity/resolution“ • Detail information about pain stimuli (sharp, localized pain) • Information about temperature • Crude touch sensation Neospinothalamic system • Tr. Spinothalamicus • Younger structure primarily connected to neocortex • „High capacity/resolution“ • Detail information about pain stimuli (sharp, localized pain) • Information about temperature • Crude touch sensation • The fibers cross midline at the level of entry segment http://neuroscience.uth.tmc.edu Dorsal column system • Tr. Spinobulbaris Dorsal column system • Tr. Spinobulbaris • The youngest system • High capacity Dorsal column system • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Proprioception Dorsal column system • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Proprioception • Fine motor control • Better object recognition • Adaptive value Dorsal column system • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Proprioception • Fine motor control • Better object recognition • Adaptive value • The fibers cross midline at the level of medulla oblongata http://neuroscience.uth.tmc.edu Dermatoms http://www.slideshare.net/drpsdeb/presentations Dermatoms http://www.slideshare.net/drpsdeb/presentations http://www.slideshare.net/CsillaEgri/presentations Trigeminal system http://www.slideshare.net/drpsdeb/presentations http://neuroscience.uth.tmc.edu Thalamus a neocortex • Almost all the afferent information gated in the thalamus • Olfaction is an exception • Bilateral connections between neocortex and thalamus http://www.slideshare.net/drpsdeb/presentations Neocortex http://www.shadmehrlab.org/Courses/physfound_files/wang_5.pdfhttp://www.slideshare.net/drpsdeb/presentations Pain • Distressing feeling associated with real or potential tissue damage • Sensor x psychological component • Physiological x pathological pain • Acute (up to 6months) x chronic (more than 6 months) https://www.cheatography.com/uploads/davidpol_1460561912_Pain_Scale__Arvin61r58.png Limbic system Navratilova E, Porreca F. Reward and motivation in pain and pain relief. Nat Neurosci. 2014;17:1304–1312. NAc – nucleus accumbens ACC – ant. Cingulate cortex. RVM – rostral ventromedial medulla Descendent pathways modulating pain • Somatosemcoric cortex • Hypotalamus • Periaquaeductal gray • Nuclei raphe Pain modulation on the spinal level Gate control theory of pain https://en.wikipedia.org/wiki/Gate_control_theory Referred pain http://www.slideshare.net/drpsdeb/presentations Phantom limb pain http://www.slideshare.net/drpsdeb/presentations