Somatosensitivity, pain Somatosensitivity-pain2 The role of nervous system Somatosensitivity-pain3 Input Integration Output REGULATION Potential input Potential output ANTICIPATION Sensor Effector Cortex Cortex Receptors/sensors Somatosensitivity-pain4 • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus http://www.slideshare.net/CsillaEgri/presentations Receptor/generator and action potential Somatosensitivity-pain5 http://www.slideshare.net/drpsdeb/presentations Receptors/sensors Somatosensitivity-pain6 • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus http://www.slideshare.net/CsillaEgri/presentations Receptors/sensors Somatosensitivity-pain7 • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus http://www.slideshare.net/CsillaEgri/presentations Receptors/sensors Somatosensitivity-pain8 • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus http://www.slideshare.net/CsillaEgri/presentations Receptors/sensors Somatosensitivity-pain9 • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus http://www.slideshare.net/CsillaEgri/presentations Receptors/sensors Somatosensitivity-pain10 • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus http://www.slideshare.net/CsillaEgri/presentations Intensity coding Somatosensitivity-pain11 http://www.slideshare.net/CsillaEgri/presentations • Amplitude of receptor potential is transtucted into the frequency of AP Intensity coding Somatosensitivity-pain12 • In the other words: an increased intensity is associated with increase in frequency of AP • A high-intensity stimulus may also activate more receptors http://neuronresearch.net/neuron/files/neuralcode.htm Intensity coding Somatosensitivity-pain13 http://slideplayer.cz/slide/3217923/ Amplitudeofreceptorpotential Actionpotentialfrequency Stimulus intensity Stimulus intensity • Relation between receptor and action potential is logarithmic Qualitative information Somatosensitivity-pain14 http://www.slideshare.net/drpsdeb/presentations • The law of specific nerve energies: The nature of perception is defined by the pathway over which the sensory information is carried • Labeled line coding define the information about quality Qualitative information Somatosensitivity-pain15 • Labeled line coding • Receptive field • Nerve stimulation mimics receptor stimulation http://www.slideshare.net/drpsdeb/presentations Receptive fields Somatosensitivity-pain16 • Various size and overaly • Small receptive field – high resolution • Spatial resolving power increased by lateral inhibition http://www.slideshare.net/drpsdeb/presentations Lateral inhibition Somatosensitivity-pain17 http://www.slideshare.net/drpsdeb/presentations Receptor adaptation Somatosensitivity-pain18 • The decline of receptor responses in spite of stimulus presence • Tonic receptors – slow adaptation – presence of stimulus, position • Phasic receptors – rapid adaptation – change of stimulus http://www.slideshare.net/CsillaEgri/presentations Receptors Somatosensitivity-pain19 • Simple • Complex • General – Superficial – somatosensors – Deep – viscerosensors – Muscles, tendons, joints – proprioceptors • Special – Part of sensory organs Receptors Somatosensitivity-pain20 • Simple • Complex • General – Superficial – somatosensors – Deep – viscerosensors – Muscles, tendons, joints – proprioceptors • Special – Part of sensory organs Receptors Somatosensitivity-pain21 http://www.slideshare.net/CsillaEgri/presentations • Simple • Complex • General – Superficial – somatosensors – Deep – viscerosensors – Muscles, tendons, joints – proprioceptors • Special – Part of sensory organs Somato/viscero/ proprio Somatosensitivity-pain22 • Somatosensitivity – Pain – Temperature – Touch • Viscerosensitivity – Pain • Proprioception – Position – Movement http://www.slideshare.net/CsillaEgri/presentations Somato/viscero/ proprio Somatosensitivity-pain23 • Somatosensitivity – Pain – Temperature – Touch • Viscerosensitivity – Pain • Proprioception – Position – Movement http://www.slideshare.net/CsillaEgri/presentations Evolutionary point of view Somatosensitivity-pain24 http://www.slideshare.net/CsillaEgri/presentations • 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 Evolutionary point of view Somatosensitivity-pain25 http://www.slideshare.net/CsillaEgri/presentations • 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 Evolutionary point of view Somatosensitivity-pain26 http://www.slideshare.net/CsillaEgri/presentations • 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 Nerve fibres Somatosensitivity-pain27 http://www.slideshare.net/CsillaEgri/presentations Nociceptors • Free nerve endings responding to high-intensiti stimuli • Stimulus – Mechanical ✓High pressure ✓Sharp object – Thermal ✓Above aprox. 45°C ✓Low treshold – variable – Chemical ✓pH ✓Mediators of inflammation and so on Somatosensitivity-pain28 Thermoreceptors Somatosensitivity-pain29 http://www.slideshare.net/CsillaEgri/presentations • Free nerve endings receptive to thermal stimuli • TRP (transient receptor potential) channels • Polymodal receptor (chemoreception, thermoreception) • Present also in many cells (including neurons, keratinocytes, mechanoreceptros) Thermoreceptors Somatosensitivity-pain30 • Perceived temperature is determined by relative activity of cold and warm receptors http://www.slideshare.net/CsillaEgri/presentations Thermoreceptors Somatosensitivity-pain31 • Mostly phasic response http://www.slideshare.net/CsillaEgri/presentations The receptors of the skin Somatosensitivity-pain32 • Simple versus complex (rapid vibration) (slow vibration, texture) (rapid vibration) (deep pressure) (movement of hairs) (sustained touch, pressure) http://www.slideshare.net/CsillaEgri/presentations The receptors of the skin Somatosensitivity-pain33 http://www.slideshare.net/CsillaEgri/presentations The receptors of the skin Somatosensitivity-pain34 http://neuroscience.uth.tmc.edu/s2/chapter02.html Viscerosensitivity Somatosensitivity-pain35 • An information from visceral and cardiovascular system • Linked to the autonomic nervous system • The most of information does not reach higher structures than hypothalamus • The most of information does not reach consciousness Proprioception Somatosensitivity-pain36 • Information from – Muscles – Tendons – Joints • Important for – Precise coordination of movements – Overload protection Somatosensory pathways Somatosensitivity-pain37 • Three systems • (Archispinothalamic) – Interconnection of adjacent segments (tr. Spinospinalis) • Paleospinothalamic – tr. Spinoreticularis, tr. Spinotectalis… • Neospinothalamic – tr. Spinothalamicus • Dorsal column system – tr. Spinobulbaris Somatosensory pathways Somatosensitivity-pain38 • Three systems • (Archispinothalamic) – Interconnection of adjacent segments (tr. Spinospinalis) • Paleospinothalamic – tr. Spinoreticularis, tr. Spinotectalis… • Neospinothalamic – tr. Spinothalamicus • Dorsal column system – tr. Spinobulbaris Somatosensory pathways Somatosensitivity-pain39 • 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 – fine touch Somatosensory pathways Somatosensitivity-pain40 • 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 – fine touch Paleospinothalamic system Somatosensitivity-pain41 • 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 Paleospinothalamic system Somatosensitivity-pain42 • 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 Paleospinothalamic system Somatosensitivity-pain43 • 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 Neospinothalamic system Somatosensitivity-pain44 • 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 Neospinothalamic system Somatosensitivity-pain45 • 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 Neospinothalamic system Somatosensitivity-pain46 • 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 Dorsal column system Somatosensitivity-pain47 • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Fine motor control • Better object recognition • Adaptive value • The fibers cross midline at the level of medulla oblongata Dorsal column system Somatosensitivity-pain48 • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Fine motor control • Better object recognition • Adaptive value • The fibers cross midline at the level of medulla oblongata Dorsal column system Somatosensitivity-pain49 • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Fine motor control • Better object recognition • Adaptive value • The fibers cross midline at the level of medulla oblongata Dorsal column system Somatosensitivity-pain50 • Tr. Spinobulbaris • The youngest system • High capacity • Tactile sensation • Vibration • Fine motor control • Better object recognition • Adaptive value • The fibers cross midline at the level of medulla oblongata Dermatoms Somatosensitivity-pain51 http://www.slideshare.net/drpsdeb/presentations http://www.slideshare.net/CsillaEgri/presentations • Somatotopic organization somatosensitve nerves Trigeminal system Somatosensitivity-pain52 • Spinal TS – Pain, temperature • Main sensory TS – Touch, proprioception http://neuroscience.uth.tmc.edu http://www.slideshare.net/drpsdeb/presentations Somatosensory pathways Somatosensitivity-pain53 http://neuroscience.uth.tmc.edu/s2/chapter02.html Tr. spinobulbaris Thalamus and neocortex Somatosensitivity-pain54 • 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 Somatosensitivity-pain55 • Somatotopic organization • Cortical magnification http://www.shadmehrlab.org/Courses/physfound_files/wang_5.pdfhttp://www.slideshare.net/drpsdeb/presentations Pain Somatosensitivity-pain56 • Distressing feeling associated with real or potential tissue damage • Sensor x psychological component • Physiological pain (nociceptor activation) • Pathological pain (not mediated by nociceptors) • Acute (up to 6months) – „activiting“ • Chronic (more than 6 months) – „devating“ https://www.cheatography.com/uploads/davidpol_1460561912_Pain_Scale__Arvin61r58.png Descendent pathways modulating pain Somatosensitivity-pain57 • Somatosemcoric cortex • Hypotalamus • Periaquaeductal gray • Nuclei raphe http://www.slideshare.net/drpsdeb/presentations Pain modulation on the spinal level Somatosensitivity-pain58 Gate control theory of pain https://en.wikipedia.org/wiki/Gate_control_theory Referred pain Somatosensitivity-pain59 http://www.slideshare.net/drpsdeb/presentations Phantom limb pain Somatosensitivity-pain60 http://www.slideshare.net/drpsdeb/presentations