[Abstract Title]. - Society for Neuroscience

compared to control-reared offspring. Furthermore, the early switch from depolarizing to
hyperpolarizing GABAergic responses in control female offspring was prevented by maternal
enrichment.
Disclosures: R. Mashoodh, None; J. Nuñez, None; C.J. Sinal, None; T.S. Perrot-Sinal, None.
Poster
281. Stress and the Brain: Early Life Experience I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 281.24/OO4
Topic: E.01.d. Development
Support: NIH grant HD049336
Title: Maternal care effects on SNB motoneurons and male copulatory behavior: The mediating
role of sensory afferent activity
Authors: *K. M. LENZ, D. R. SENGELAUB;
Psychol & Brain Sci., Indiana Univ., Bloomington, IN
Abstract: Early maternal care shapes the sexual behavior of male rats, with reductions in
maternal licking of the perineum producing adult copulatory deficits. Maternal care also
influences the development of the spinal nucleus of the bulbocavernosus (SNB), a sexually
dimorphic motor nucleus in the lumbosacral spinal cord that controls the penile reflexes involved
in copulation. Previous research has shown that reductions in maternal licking produce decreased
adult SNB motoneuron number, size and dendritic length in offspring, especially in the rostral
portion of the nucleus. We have begun to study the mechanisms through which maternal licking
influences SNB development, with a focus on cutaneous sensory afferents from the perineal skin.
Our previous work has shown that these sensory afferents are distributed in a caudally biased
manner relative to the SNB dendritic field, suggesting that these sensory afferents may
sufficiently support the caudal SNB dendritic arbor even when maternal licking is decreased, but
render the rostral arbor more vulnerable to decreases in afferent activity. In the current studies,
we used immediate early gene analysis to investigate whether licking-like tactile stimulation of
the perineum increases local spinal cord activity in the area of the SNB dendritic field.
We simulated maternal licking by stroking neonatal rats with a paintbrush, and subsequently
measured the expression of the immediate early gene product, Fos, in the lumbosacral spinal
cord using immunohistochemistry. Relative to unstimulated controls, pups that received lickinglike
stimulation showed a dramatic increase in the number of Fos-positive neurons in the area of
the SNB dendritic field, suggesting that maternal licking increases local neuronal activity during