PSY280 AUGUST 7.docx

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University of Toronto St. George

PSY280 AUGUST 7, 2012 PROPRIOCEPTION Somat cortex in parietal Somatosensation - Includes touch - Think of som of body think of touch - Touch allows us to interact with environment, effectionate - Tocuh we use when cant see objects – looking through purse - Reproduction – touch - Temp relative to temp, regulate internal state and external env - Somat dtetcing threat to body – notice when there is threat to internal state - Prop – detect limbs in space postion – kinesthesia type of propsenation intercgangably - Olympics prop gymnast hit those beams Somat - Diff fibers for dif senses like vison and hearing segregated independt and inergrate higher levels - Dif receptors - Machno – pressure changes – touch - Thermo – changes in temp – heat vs cold - Nociceptor – pain identify damage to skin or internal organs - Propiceptor – allow us detect position if limbs all receptors linked to fibers - A alpha - All fibers linked to spec rec st - 1 prop - 2 touch mach - 3 pain temp - Fin temp pain an itch - Thinner and less myleinated - Myleianted prop - Final is non myle very little Skin - Touch temp and pain is skin - Macono therm in skin - Prop in muscles and tendons - Skin 3 layers - Epi outher layer - Dermis - And subca - Epi dead skin of dermis provides barrier of moisture - Dermis machno rec and rec to touch and dermis largest layer as die pushed to dermis - Sub consist of fat cells - Skin largestheaviest organ, 15 feet extende and 10 pound, complex - All body skin Contd - Can be hairy or hairless - Glabrous hairless - Hairy skin and glab free - Majority is hairy and some hairless - Glab will be palms hands and feetsole, lips, fingertips toes genitals and eye lids - Hairless more sensitive and more machno rec, glab more sens Mach - Touch - Change in pressure or mech - A beta - Middle range of myleinaion - Can be charactrerezied by type of stim - Size of receptive field - And rate of adapation Stim - Vibrating fast perception of warmth – cross perception Size - Vision are visual for touch is skin - Small or large rec filed - Large less acuity not distinct difference across - Small know touches certain touch either on or off rec filed Adpt - Fast or slow - Fast firing bursts when stim on or off body, applying pressure fire when pressure on and then off as soon stim off - Not in between though - Fast changes in pressure and senst to temperal pattern time stim on and off - Slow respond to cont stimulation – on then stays bursts till away contin pressure not time or temperal sens as fast Mach - Dist rate of firing recp field - 4 - Based on small rec field and adaptation - 4 machno based on adap and large or small rec field Contd - Sens to dif stim - Messner slow or short vib – grip slip – grapping cup to heavy and sliping detects slip, short vibrations that are quick - Merkel – short freq but sent to indent – basic pressure – change in indent of skin first hits you first contact with stimulus – texter and patern perception - Pac – highfrq – vibration – skin contact – detects when first make contact – merkel text and pattern – pac when first in contact – pac skin contact and vibration that occur - Ruffini – stretching – bc more into grip bc stretch skin or contraxcitng change in stretching identify how much pressure to grab object – stable grip messner slip - Have key find in pocket shape merkel pressure the texture, shape of finger to grasp key the ruffini grip, not slip the messner hold right pressure, into houselock key to lock the pacinian Tactile - Detect details on skin - Fingertips two points detect diff in pressure - On formarm on point bc tactile less - Ta 2 point threshold - Grating - Or raise patter - 2 point min sep to perceive to two stimuli - Tocu skin two point and when 2 points and not one - Grating – groved stim with orientation and tell direction of grating - Raised – patter like braile and identify dif in surface Contd - Varies diff parts of body - Hairless skin areas - Min threshold toes less for legs - Why diff Contd - Densitiy machno recpetors - Firing rate for intendation - Firing rate of merkel is sim to ind – sens to patter high ta - Pacin not diction of patter - Dens of merkel more grouped together - H dens h ta Tact ac - Small rec filed larger area of cortex and less overlap - So same surface small rec two points disting bc separate cells - Larger cortical areas - Homunculus - Hands and moth larger cortical rep in som cortex then areas of the body so can be distinguished - 2 points in finger diff areas – type of mag same in fovea - Test talk about similarities - Fovea larger in primary visual cortex - Forearm they overlap fingers two points Vibrations - Ability dif in vibration in pcinina - Snese vibration by detecting rapid changes in pressure - Onion - Layers in between is flkuid - Rapid vibration they layer penetrate vibration of fluid - Act fiber - Cont pressure holding point or touch area then not cuase signal to send down to fibr, need fast Texture - Two cues to detect texture - Duplex theory - Two are spatial and temperal - Spatial for fine detail size shape and distribution of texture elements - Temperal – dtect fine texture – has use temperal move hand casue diff in vibration get information of texture of object - Rocks vibration diff then smooth surface - Pac for vibration and merkel for fine detail Contd - Evidence - Adaptation - Adapt machno to high freq elem of pac 250 hertz - Messner 10 - Messner still goos - Knock pac then texture drops to change - Vibration pac important and needed to detect texture perception Objects - Haptic - Knowledge gained of 3d world of sense of touch - Gym bag find socks - Ability to identify objects with only touch - Sens moto and cog - Sens touch temp and texture and prop where hand is over surface - Allows use touch to identidfy objects - Motor movement of finger and hands, move to detec - Cog – high processes senddown signal and rec objects, cup is circular - 3 systems rely on haptic perception Objects - Rec by touch is effortful - Visual very fast - Exp procesueed to identify certain prop - Consistirncy pressure - Allow us identify objects haptic perception Prop - Mach in skin - Prop in muscles and tendons - Provide info of motion and body position of limbs and muscles - Muscle spindle – located in muscle - Golgi around tendons that attach to muscle - Spindle to length leng contracts spdnle to brain - Golgi tenion – Musc spindle - Linked to interfual fibers linked inside musle - Extra provide muscular motion everytime move muscles its those that – extra move stretch or contract - Spindles to central nervous system by ia path and to intra which is spindle send to cortex and receive - Receive gamma inre - Alpha to extra - Extra move so does intra bc lnked - Intra how much stretching and rate to brain Pro - Stretch reflex – strect musle contracts in response - Holding tray gets heavy lengthens goes to brain ia and motor neurons down to muscles or contract - Stretch then conter to contract – ia to brain then send back down using alpha Contd - Vestibular - Inner ear cochlea – behind coch has ves aparr 3 semi circu canalas - Va – info of bodies sense of tilt lean back - And head moving - Hea
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