Download Sensory axons in peripheral nerves

‫פיסיולוגיה מורחב‬
08-9
Somatosensory System
and Pain
lecture 4: Afferent input to the spinal cord
Prof. Marshall Devor, Ph.D.
Dept. of Cell & Animal Biology and
Center for Research on Pain
Institute of Life Sciences
Hebrew University of Jerusalem
flexor reflex
• flexor reflex afferents
• nociceptors
• multisegmental response
Collateral branching
flexion 
extension 
nociceptive afferent
flexor reflex
segmental reflex
primary
sensory
neurons
D
V
somatotopic mapping
rostral
(note overlapping RFs)
rostral
cranial
cervical
thoracic
lumbar
sacral
coccygeal
caudal
caudal
substantia gelatinosa
A
Aδ
C
Rexed laminae
dorsal horn
ventral horn
SP
substance P – neurotransmitter/ neuromodulator
NK1
neurokinin 1 (NK1) SP receptor
• somatotopic mapping
• Rexed’s laminae
• divergence
• convergence
somatotopic map
dermatome
T11
T10
dermatome
L1
T10-T11 overlap
L4
L6
opthalmic division
maxillary division
mandibular division
trigeminal system V1,V2,V3
V = 5th cranial nerve
caudal trigeminal nucleus
= dorsal horn of V
rostral
fore
distal
rostro-caudal
proximo-distal
proximal
proximal
hind
Lat.
somatotopic map
distal
Med.
caudal
Lat.
somatosensory
mapping
succinyl dehydrogenase
• somatotopic mapping
• Rexed’s laminae
• divergence
• convergence
Rexed’s laminae
some SG neurons are
"nociceptive specific"
low threshold specific
WDR
multireceptive
X
BT+
P+
P-
synaptic input into the dorsal horn
divergence
Divergence
SA1
Convergence
Convergence
divergence
convergence
‫פיסיולוגיה מורחב‬
Somatosensory System
and Pain
lecture 4: Afferent input to the spinal cord
Prof. Marshall Devor, Ph.D.
Dept. of Cell & Animal Biology and
Center for Research on Pain
Institute of Life Sciences
Hebrew University of Jerusalem
simple behavior
Muscle spindle
afferent (DRG)
Muscle spindle
‫כישור שריר‬
Polysynaptic
antagonist muscle
(inhibitory interneuron)
Monosynaptic
agonist muscle
myotactic (stretch) reflex
…demo