5 Somatosensitivity, viscerosensititvity, proprioception and pain I 1 The role of nervous system Input Integration Output REGULATIONREGULATION Potential input Potential output ANTICIPATIONANTICIPATION Sensor Effector Cortex Cortex 2 Receptors/sensors • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus • Mechanoreceptors • Thermoreceptors • Chemoreceptors • Fotoreceptors http://www.slideshare.net/CsillaEgri/presentations 3 Receptor/generator and action potential http://www.slideshare.net/drpsdeb/presentations 4 Receptors/sensors • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus • Mechanoreceptors • Thermoreceptors • Chemoreceptors • Fotoreceptors http://www.slideshare.net/CsillaEgri/presentations 5 Receptors/sensors • Energy convertor – Signal reception – Signal transformation • Receptor potential – Generator potential • Action potential • Adequate stimulus • Non adequate stimulus • Mechanoreceptors • Thermoreceptors • Chemoreceptors • Fotoreceptors http://www.slideshare.net/CsillaEgri/presentations 6 Receptors/sensors • Energy convertor – Signal reception – Signal transformation • Receptor potential • Generator potential • Action potential • Adequate stimulus • Non adequate stimulus • Mechanoreceptors • Thermoreceptors • Chemoreceptors • Fotoreceptors http://www.slideshare.net/CsillaEgri/presentations 7 Receptors/sensors • Energy convertor – Signal reception – Signal transformation • Receptor potential • Generator potential • Action potential • Adequate stimulus • Non adequate stimulus • Mechanoreceptors • Thermoreceptors • Chemoreceptors • Fotoreceptors http://www.slideshare.net/CsillaEgri/presentations 8 Receptors/sensors • Energy convertor – Signal reception – Signal transformation • Receptor potential • Generator potential • Action potential • Adequate stimulus • Non adequate stimulus • Mechanoreceptors • Thermoreceptors • Chemoreceptors • Fotoreceptors http://www.slideshare.net/CsillaEgri/presentations 9 Intensity coding • Amplitude of receptor potential is transtucted into the frequency of AP http://www.slideshare.net/CsillaEgri/presentations 10 Intensity coding • In hte 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 11 Intensity coding Relation between receptor and action potential is logarithmic http://slideplayer.cz/slide/3217923/ Amplitudeofreceptorpotential Actionpotentialfrequency Stimulus intensity Stimulus intensity 12 Qualitative information • 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 http://www.slideshare.net/drpsdeb/presentations 13 Qualitative information • Labeled line coding • Receptive field • Nerve stimulation mimics receptor stimulation http://www.slideshare.net/drpsdeb/presentations 14 Receptive fields • Various size and overlay • Small receptive field – high resolution • Spatial resolving power increased by lateral inhibition http://www.slideshare.net/drpsdeb/presentations 15 Lateral inhibition http://www.slideshare.net/drpsdeb/presentations 16 Receptor adaptation • 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 17 Receptors • Simple • Complex • General – Superficial – somatosensors – Deep – viscerosensors – Muscles, tendons, joints – proprioceptors • Special – Part of sensory organs • Mechanoreceptors • Termoreceptors • Chemoreceptors • Fotoreceptors 18 Receptors • Simple • Complex • General – Superficial – somatosensors – Deep – viscerosensors – Muscles, tendons, joints – proprioceptors • Special – Part of sensory organs • Mechanoreceptors • Termoreceptors • Chemoreceptors • Photoreceptors 19 Receptors • Simple • Complex • General – Superficial – somatosensors – Deep – viscerosensors – Muscles, tendons, joints – proprioceptors • Special – Part of sensory organs • Mechanoreceptors • Termoreceptors • Chemoreceptors • Photoreceptors http://www.slideshare.net/CsillaEgri/presentations 20 Somato/viscero/ proprio sensitivity • Somatosemsitivity – Pain – Temperature – Touch • Viscerosensitivity – Pain • Proprioception – Position – Movement http://www.slideshare.net/CsillaEgri/presentations 21 Somato/viscero/ proprio sensitivity • Somatosemsitivity – Pain – Temperature – Touch • Viscerosensitivity – Pain • Proprioception – Position – Movement http://www.slideshare.net/CsillaEgri/presentations The majority of information does not reach cousciousnes 22 Somato/viscero/ proprio sensitivity • Somatosemsitivity – Pain – Temperature – Touch • Viscerosensitivity – Pain • Proprioception – Position – Movement http://www.slideshare.net/CsillaEgri/presentations The majority of information does not reach cousciousnes Evolutionary point of view 23 Evolutionary point of view • The signals indicating potential damage are the most important and the corresponding systems evolved early – Pain – Temperature http://www.slideshare.net/CsillaEgri/presentations http://www.slideshare.net/CsillaEgri/presentations 24 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 25 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 26 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 27 Free nerve endindgs • Non-specialized nerve endings • Polymodal – Nociception – Termoreception – Mechanoreception • A delta fibres • C fibres http://www.slideshare.net/CsillaEgri/presentations 28 Nerve fibres http://www.slideshare.net/CsillaEgri/presentations 29 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 30 Thermoreceptors • Free nerve endings receptive to thermal stimuli • TRP (transient receptor potential) channels • Each subtype of TRP channel receptive to sensitive to a certain temperature and chemical substance http://www.slideshare.net/CsillaEgri/presentations 31 Thermoreceptors • Perceived temperature is determined by relative activity of cold and warm receptors http://www.slideshare.net/CsillaEgri/presentations 32 Thermoreceptors • Mostly phasic response http://www.slideshare.net/CsillaEgri/presentations 33 The receptors of the skin (rapid vibration) (slow vibration, texture) (rapid vibration) (deep pressure) (movement of hairs) (sustained touch, pressure) Simple versus complex http://www.slideshare.net/CsillaEgri/presentations 34 The receptors of the skin http://www.slideshare.net/CsillaEgri/presentations 35 The receptors of the skin http://neuroscience.uth.tmc.edu/s2/chapter02.html 36