Anatomical Substrates
of
Somatic Sensation
Dorsal Column-Medial Lemniscal System
Dorsal column-medial lemniscal system: Mechanical sensations
Anterolateral system:
Pain,
Thermal, Itch
Mechanoreceptors
are encapsulated
Nociceptors,
thermoreceptors, & itch receptors are
bare nerve endings
Key Characteristics of DRG Neurons
CNS Neurons have Receptive Fields
Key Characteristics of DRG Neurons
Mechano-
receptor
receptive
fields
Mechano-
receptor
receptive
fields
Nociceptors,
thermoreceptors, & itch receptors are
bare nerve endings
Nociceptors
respond to
noxious
stimuli
Peripheral
nerve
cross
section
Fiber Histogram: Sensory axon innervating the skin
Fiber Histogram: Sensory axon innervating a muscle
Receptor projections to systems
Brodmann’s
cytoarchitectonic
areas
Somatic Sensory Cortical
Areas
for Mechanosensations