Faculty Bibliography

Previous studies have shown that rat pups have an enhanced metabolic activity to familiar odors in specific glomeruli of the olfactory bulb. The present study examined extracellularly recorded mitral cell responses to odors in this glomerular region, in odor-familiar and odor-unfamiliar pups. Mitral cells in odor-familiar pups had significantly fewer excitatory and more inhibitory responses to the familiar odor than controls. There were no differences between groups in responses to a novel odor. These results demonstrate that neonatal exposure to odors selectively alters subsequent mitral cell responsiveness to that odor

The postnatal development of short-term potentiation (STP) and long-term potentiation (LTP) was examined in the neocortex and dentate gyrus of rats aged 7 days to adult. STP and LTP of the transcallosal response in the neocortex could not be demonstrated until the third postnatal week. STP and LTP of the perforant path-dentate response could not be demonstrated until the second postnatal week. In both cases, STP appeared several days before LTP. Structural and neurochemical correlates of STP/LTP development, and their implications for possible STP/LTP mechanisms, are discussed

The postnatal development of short-term potentiation (STP) and long-term potentiation (LTP) of the transcallosal response (TCR) was examined in anesthetized rats, aged 7 days (PN7) to adult (greater than or equal to PN180). Stimulation of callosal fibers produced a biphasic, positive-negative TCR recorded at the surface of the anterior neocortex in all age groups. The TCR showed a decrease in threshold, latency and halfwidth, and an increase in peak amplitude with age. High frequency callosal stimulation produced marked STP and LTP of the mature TCR. STP in young animals, however, could not be reliably detected until after PN16. LTP was not detected until PN18. STP and LTP approached adult levels rapidly after their initial appearance. The correlations between STP/LTP onset and development and known structural developments such as initial synaptogenesis, spine formation and myelinogenesis were not particularly strong. The implications of these results for specific hypotheses of STP/LTP mechanisms were discussed