Touch

kinesthesia

perception of the position and movement of our limbs in space

proprioception

preception mediated by kinesthetic and internal receptors

somatosensation

collecitve sensory signals from skin, msucles, tendons, joints and internal receptors

tactile touch

the experience of mechanical interactions with the skin

haptic perception

processing of inputs from discrimitative touch in the context of active information seeking

interoception

the sensation of the internal state of the body

affective touch

the social and emotional aspects of touch

A-alpha fibers

wide diameter, myelinated sensory nerve fibers that transmit signals from proprioceptive receptors in muscles and tendons

A-beta fibers

wide diameter, myelinated sensory nerve fibers that transmit signals from mechanical stimulation

A-delta fibers

intermediate sized, myelinated sensory nerve fibers that transmit pain and temperature signals

C fibers

narrow diameter, unmyelinated sensory nerve fibers that transmit pain and temperature signals

meissner corpuscles

fast adapting, small receptive fields that detect low frequency vibrations

merkel cells

slow adaptation, small receptive fields

pacinian corpuscles

fast adaptation, large receptive fields that detect high frequency vibration

ruffini endings

slow adaptation, large receptive fields, detect finger position

kinesthetic receptors

mechanoreceptors in muscles, tendons and joints

muscle spindle

a sensory receptor located in a muscle that senses its tension

thermoreceptors

sensory receptors that signal information about changes in skin temperature

warmth fibers

sensory nerve fiber that senses when temperature increases

cold fibres

sensory nerve fiber that sense when temp decreases

free nerve fibres

they have raw nerve endings rather than specialized receptors

Nocioceptors

transmit info about noxious stimulation or pain

thermo TRP channel

thermally sensitive transient receptor potential ion channel found in sensory neurons

pruriceptors

neural fiber that carries the sensation of itchiness

labeled lines

each fiber type from the skin codes a particular touch sensation

somatotopic organization

adjacent areas of the skin project to adjacent areas in the spinal cord

spinothalamic pathway

carries most. ofthe information about skin temperature and pain

dorsal column medial lemniscal pathway

carries signal from skin, muscles, tendons and joints

cuneate

extracts information about orientations and movement of object edges

gracile

extracts fine touch information and proprioceptive information

thalamus

multisensory integration of touch with vision and auditory information

emotional touch

processes pleasant touch sensation, relates touch to emotional state

interoception

connection of touch to internal body states, especially emotional state

salience network

identify and attend to important stimuli

insula functions

emotional touch, interoception, pain, salience networks

anterior cingulate cortex functions

emotional regulation, pain processing, salience network

tactile agnosia

the inability to identify objects by touch caused by lesions to the parietal lobe

allodynia

when pleasurable touch sensations cause pain instead

hyperesthesia

hypersensitivity to touch all over the body resulting in avoidance of touch

dyesthesia

distortion of touch sensation

amorphagnosia

inability to dicern the shape of an object by touch

associative tactile agnosia

inability to associate the percieved tactile features of an object with its name or function

neuroplasticity

the ability of neural circuits to undergo changes in function or organization as a result of previous activity

phantom limb

sensation percieved from a physically amputated limb of the body

discriminative touch

actively using touch to sense and identify the world

two point threshold

the minimum distance at which two stimuli are just felt as seperate

pleasant touch

mediated by unmyelinated peripheral C fibers known as tacticle afferents

anterior cingulate cognitive response to pain

associated with the percieved unpleasantness of pain sensations

prefrontal cortex response to pain

concerned with cognition and executive control

gate control theory of pain

inhibitory neurons decide which signals to send and which to block

analegsia

decreasing pain sensation during conscious experience

endogenous opiates

a chemical that blocks the release or uptake of neurotransmitters to send pain signals

placebo

experience an expected effect when the drug that induces the event is not present

hyperalgesia

a heightened response to a normally painful stimulus

nocebo effect

experiencing an increase in pain when there is an expectation that pain will occur

haptic perception

knowledge of the world that is derived from sensory receptors in skin, muscles, tendons and jounts

somatosensory preparation

evaluates and predicts sensation based on object knowledge and multisensory input

exploratory procedure

a hand movement pattern used to contact objects in order to percieve their properties

egocenter

the center of a reference frame used to represent locations relative to the body

frame of reference

the coordinate system used to define locations in space