5 Somatosensory system

• Meissner’s corpuscles (RAI)

  • light touch, low-frequence vibration

• Pacinian corpuscles (RAII)

  • largest receptors

  • transient pressure, high-frequency vibration

• Merkel’s disks (SAI)

  • specialized non-neural epithelial cell

  • edges, form, texture

• Ruffini’s endings (SAII)

  • skin stretch, Hand position

• free nerve endings (unmyelinated)

  • pain, temperature

I = small receptive; field II = large receptive field

the area of skin where stimulation changes the firing of a sensory neuron

• Small

  • higher precision

• Large

  • broader sampling, lower localization accuracy