- 947176 한 종 완 -

Lines of evidence supporting the role of different neuron
types in pain discrimination.

Neuron type Line of evidence★
1 2 3 4
Mechanosensitiveprimary afferents
high-threshold A delta
low sensitivity/moderate pressure A delta
high-threshold C
low-threshold A delta /A beta
low-threshold C
. ++. ++
. ++. ++
. ++. ++
. . .+
. . ..
Thermosensitiveprimary afferent
cold A delta
warm A delta /C
high-threshold A delta /C
.+.+
.++
.+..
Mechanothermosen-sitive primary afferents
heat nociceptive A delta
polymodal nociceptive C
mechano-cold nociceptive A delta /C
++++++++
++++++++
.+..
Spinal cord and brain stem
dorsal horn and trigeminal caudalis - WDR
dorsal horn and trigeminal caudalis - NS
n.gigantocellularis - NS and WDR
other - NS and WDR
++++++++
.++++++
++++
.+..
Thalamic nuclei
ventroposterior - WDR
ventroposterior - NS
posterior group -WDR and NS
medial group - WDR
medial group - NS
.+.+
.+.+
.+.+
.+.+
.+.+
Cerebral cortex
WDR
NS
.+.+
.+.+
★LIne of evidence1 = selective stimulation produce pain.
2 = maximum response to noxious stimuli.
3 = selective manipulations reduce neural res- ponses and pain.
4 = appropriate anatomical connection.

WDR = Wide dynamic range neuron.
NS = Nociceptive-specific neuron. ++ strong evidence ; + weak evidence.


References

Willam D.Willis ; The pain system (1985), P.20.










BRAIN FACTS