Dorsal Column-Medial Lemniscal System
| •Mediates mechanical sensations | |
| -touch, limb position sense, vibration sense | |
| •Well established; clinical & experimental |
| •Mediates protective sensations | |
| -Pain | |
| -Temperature (cold & warmth) | |
| -Itch | |
| •Not as definitively established as is the DC-ML system for touch |
| Peripheral somatic sensory receptors are sensitive to different stimulus qualities | ||
| Mechanical | ||
| Thermal (warm, cold) | ||
| Noxious (mechanical, thermal, polymodal) | ||
| Different receptor classes provide
input to different somatic sensory pathways |
||
| Differential thalamic and cortical localization | ||
Dorsal column-medial lemniscal system: Mechanical sensations
Anterolateral system:
Pain, Thermal, Itch
Nociceptors,
thermoreceptors, & itch receptors are
bare nerve endings
Mechano-
receptor
receptive
fields
Fiber Histogram: Sensory axon innervating the skin
1° Somatic Sensory Cortex Output Systems
| Early morphological specialization of DRG neurons sets stage for separate mechanosensory and pain/temp/itch systems | |