PSYC1002 Lecture Notes - Lecture 14: Adobe After Effects, Somatosensory System, Proprioception
19 May 2018
School
Department
Course
Professor
Somatosensory system
Premature babies gain wait faster and go home sooner if stimulated by hand massage
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Infant monkeys allowed to see, hear and smell but not touch, mothers become unhappy
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Intimate relationship between touch and emotions
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Importance of touch
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Opponent-like after-effects - texture contrast after-effects (after touching
something rough, something of medium roughness feels smoother), can apply to
temp as well
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Tactile afterimages
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Importance of movement in perceiving spatial patterns in the skin
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Non-moving objects on skin less salient than when skin first perturbed
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Tactile adaptation
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Tactile system evolved to perceive best when exploring
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Active vs passive touch
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Dynamic sensitivity in skin senses
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Touch
and Proprioception
Somatic sensory system
Light, vibration, pressure, cutaneous (skin) tension
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Identify shapes and texture of objects
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Monitor internal and external forces acting on body
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Detection of MECHANICAL STIMULI
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Detect potentially harmful circumstances
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Detection of PAIN AND TEMPERATURE
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Has 2 major subsystems
Stimuli applied to skin deform or change the nerve endings
1.
Affects ionic permeability of the receptor cell membrane
2.
Induces depolarising current in the nerve ending
3.
Triggers action potential (sensory transduction)
4.
All sensory systems work in same general way
Interoception
Mechanosensory processing
Perceptual quality (what and where it is) depends on receptors that respond and where they
project
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Quantity and strength - depends on no. of action potentials generated
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Stimuli
Cutaneous (on skin) and subcutaneous mechanoreceptors at body surface
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Detection of external stimuli
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Receptors located in muscles, joints, deep structures
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Monitor mechanical forces generated by musculoskeletal system
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Proprioceptors
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Receptor types
Mechanoreceptors
Touch fibre types
L3 - the body senses
Saturday, 4 November 2017
6:33 PM
perception Page 1
Mechanoreceptors
elongated receptors contain one or more afferent nerve fibres
that generate rapidly adapting action potential following
minimal skin depression
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Found just beneath epidermis of fingers, palms and soles
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Most common receptors of glabrous skin (smooth and hairless
type)
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Respond best in range of low-freq vibrations 30-50Hz
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Screen clipping taken: 15/11/2017 10:05 PM
Meissner corpuscles
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Large encapsulations
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Found in subcutaneous tissue and gut
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Onion like capsule and fluid filled inner space with one or
more rapidly adapting afferent axons
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Capsule acts like filter, allows on transient high-freq
disturbances 250-350Hz to activate nerve endings
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Stimulation -> vibration/tickle
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Screen clipping taken: 15/11/2017 10:07 PM
Pacinian corpuscles
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Rapidly adapting - info about change or dynamical quality of stimuli
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In epidermis
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About 25% receptors in hand
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Dense in fingertips, lips, external genitalia
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Stimulation -> sense of light pressure
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Merkel disks
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Slowly adapting - info about shape, edges, rough texture, persisting
features
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Touch fibre types
perception Page 2
Document Summary
Premature babies gain wait faster and go home sooner if stimulated by hand massage. Infant monkeys allowed to see, hear and smell but not touch, mothers become unhappy. Opponent-like after-effects - texture contrast after-effects (after touching something rough, something of medium roughness feels smoother), can apply to temp as well. Importance of movement in perceiving spatial patterns in the skin. Non-moving objects on skin less salient than when skin first perturbed. Tactile system evolved to perceive best when exploring and proprioception. Monitor internal and external forces acting on body. All sensory systems work in same general way. Stimuli applied to skin deform or change the nerve endings. Affects ionic permeability of the receptor cell membrane. Perceptual quality (what and where it is) depends on receptors that respond and where they project. Quantity and strength - depends on no. of action potentials generated. Cutaneous (on skin) and subcutaneous mechanoreceptors at body surface.
