Behavioral Neuroscience, lecture on Lordosis Behavior
LORDOSIS
III. Sensory Reception - Afferent Circuitry
!First Neural Circuit for a Mammalian Behaivor!
A. Tactile Receptors
1. male's body against female's rump region
a. or sensory inspection
2. Ruffini endings
a. slowly adapting: to a barrage of impulses
i. sub-cutaneous mechanoreceptive units with soma in
dorsal root ganglia
b. respond to sustained pressure stimulation
i. most primary sensory neurons respond
ii. only pressure units and type I (hair + pressure) units
have sustained responses to lordosis-triggering
pressure
(1) specialized sensory response
(a) Ruffini end organs
(i) run parallel to skin
(ii) also found in finger tips
(iii) respond to slippage, chage of angle, thermoreception
(2) spatial summation across pressure units
facilitates reflex
c. E2 stimulates increased Ruffini receptors
i. expanded receptive field of pudendal nerve
(1) broader
d. mating/repeated mating can increase receptivity
i. increased LQ
ii. requires intromission - vaginal, cervical stimulation
3. Sensory fibers to spinal cord
a. from skin of rump, tail base and perineum
i. via the dorsal roots at L5, L6 and S1
ii. pudendal nerve
b. from flanks
i. via L1 and L2
c. cell bodies in dorsal root ganglia
d. the terminals are deep in the dorsal horn
of the spinal cord
i. units responding only to pressure
found primarily in the intermediate gray
ii. Units responding to movement of hair located
more dorsally in the dorsal horn
iii. Units responding to subdermal stimulation
usually found at greater depths
e. transmitters of these neurons are colocalized peptides
i. inhibited by another peptide