somatosensation ( physiology of touch )

somatosensation

Collectively, sensory signals from the skin, muscles, tendons, joints, and internal receptors

tactile, thermal, nociception, kinesthesia

Classes of sensation

kinesthesia

Perception of the position and movement of our limbs in space

proprioception

Perception mediated by kinesthesia and internal receptors

type 1

Small receptive field

type 2

large receptive field

fast adaptation

Means the receptor/fiber responds transiently

slow adaptation

Means that the receptor/fiber has a sustained response

mechanoreceptors

Meissener corpuscles, Merkel cell neurite complexes, ruffini endings, pacinian corpuscles

Meissner corpuscles

Fast adaptation, small receptive field (FA 1)

Merkel cell neurite complexes

Slow adaptation, small receptive field (SA 1)

Ruffini endings

Slow adaptation, large receptive field (SA2)

pacinian corpuscles

Fast adaptation, large receptive field (FA 2)

Thermoreceptor

e sensory receptors that signal information about changes in skin temperature – Receptors are bare nerve endings

nociceptor

sensory receptors that transmit information about noxious stimulation that causes damage or potential damage to skin – Receptors are bare nerve endings

a-delta fibers and c fibers

Groups of nociceptors

a-delta fibers

Quick sharp pain, Intermediate-sized, myelinated sensory nerve fibers that transmit pain and temperature signals; better for localizing pain

c-fibers

Throbbing pain, Narrow-diameter, unmyelinated sensory nerve fibers that transmit pain and temperature signals

muscle spindles

sensory receptors located in muscles that senses their tension

Golgi tendon organs

Sensory receptors in tendons that signal tension in muscles attached to tendons

labeled lines

Each fiber type from the skin codes a particular touch sensation

dorsal horn

horn is organized into multiple layers, or laminae, every skin mechanoreceptor projects into the dorsal horn

spinothalamic

Pathway married most of the info about skin and pain (slower)

dorsal column-medial lemniscal (DCML)

Pathway carries skin from skin, muscle, tendons, and joints

homunculus

Maplike represntation of regions of body in the brain

neural plasticity

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

body image

Refers to our mental representation of our body’s extemn and position in space

anterior cingulate

A region of the brain associated with the perceived unpleasantness of pain sensations

prefrontal cortex

A region of the brain concerned with cognition and executive control-may contribute to pain sensitization

analgesia

Decreasing pain sensation during conscious

gate control theory of pain

Description of the pain transmitting system that incorporated modulating signals from the brain

haptic perception

refers to the knowledge of the world that is derived from sensory receptors in skin, muscles, joints, tendons, usually involving active exploration

exploratory procedure

stereotypical hand movement pattern used to contact objects in order to perceive their properties; each exploratory procedure is best for determining one or more object properties

frame of reference

coordinate system used to define locations in space

egocenter

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

what system

geometric properties of objects are most important for visual recognition

action for perception

using hands to actively explore the world of surfaces and objects outside of our bodies

where system

knowing where objects are in the environment using only touch perception - finding snooze button on alarm clock in the morning