Plasticity of the rat olfactory bulb during postnatal development: a parametric MRI study.

We analyzed modifications in transversal relaxation time (T2) and regional cerebral blood volume (rCBV) in two areas of the limbic system,i.e., olfactory bulb (OB) and amygdala (AMY), in pre-puberty and post-puberty female rats. The aim of this work was to extend the knowledgeabout physiological modifications of these MRI parameters at different developmental phases. No significant difference was observed in T2values of the OB between the two groups (pre-puberty: T2 = 86.92 ± 8.57 ms, post-puberty: T2 = 88.11 ± 13.06 ms; mean ± S.D.). On thecontrary T2 values of the AMY were significantly different (P = 0.0001) between the two groups (pre-puberty 76.08 ± 3.2, post-puberty81.77 ± 11.77 ms). rCBV values of OB were significantly different (P = 0.0025) between pre-puberty (0.38 ± 0.12 a.u.) and post-pubertyfemale rats (0.15±0.09 a.u.). A significant decrease in rCBV (P = 5.1×10−13) between pre-puberty and post-puberty females (pre-puberty:0.36 ± 0.12, post-puberty: 0.07 ± 0.05 a.u.) was also observed in the AMY. These findings suggest that in the limbic system, microvascularplasticity parallels neuronal maturation and indicate the importance of an appropriate baseline study in experiments dealing with the limbicsystem performed at different time-points.© 2004 Elsevier Ireland Ltd. All rights reserved.