p27(KIP1) regulates neurogenesis in the rostral migratory stream and olfactory bulb of the postnatal mouse.

Neuronal progenitor cells of the anterior subventricular zone (SVZa) migrate along the rostral migratory stream (RMS) to the olfactory bulb, where they exit the cell cycle and differentiate. The molecular mechanisms that regulate SVZa progenitor proliferation and cell-cycle exit are largely undefined. We investigated the role of p27(KIP1) in regulating cell proliferation and survival in the RMS and olfactory bulb between postnatal day 1 (P1) and P14, the peak period of olfactory bulb neuron generation.

Subventricular zone neuronal progenitors undergo multiple divisions and retract their processes prior to each cytokinesis.

Mitotically active progenitor cells from the anterior portion of the forebrain subventricular zone (SVZa), which give rise throughout life to olfactory bulb interneurons, bear processes and express neuronal markers. To understand how rodent SVZa neuronal progenitors coordinate division and process formation, we used time-lapse videomicroscopy to analyse the proliferative behavior of SVZa progenitors in dissociated cell culture continuously for up to five generations. The cell cycle time of these cultured SVZa cells assessed videomicroscopically (cytokinesis to cytokinesis) was similar to the cell cycle time along the rostral migratory stream in vivo (14-17 h).

Prenatal development of the rodent rostral migratory stream.

The aim of this study was to elucidate the embryological origins of the unique neuronal progenitor cells that form the rostral migratory stream (RMS), the path traversed by cells from the anterior part of the forebrain subventricular zone (SVZa) en route to the olfactory bulb. To determine when and where cells constituting the RMS initially exhibit their characteristic neuronal phenotype and high mitotic capacity, we analyzed the cells of the rat forebrain between embryonic day 14 (E14) and postnatal day 2 (P2). At E14, cells with a neuronal phenotype were observed within the ventricular zone in close proximity to the mantle layer of the future olfactory bulb.

Intrinsic and extrinsic regulation of the proliferation and differentiation of cells in the rodent rostral migratory stream.

An overriding principle of development is that neurons become permanently postmitotic once they initiate differentiation. Work in our laboratory, however, has provided evidence for a population of progenitor cells in mammalian forebrain that express properties of differentiated neurons, even though they continue to divide. These neuronal progenitor cells are situated in the rostral migratory stream (RMS), which extends from a specialized portion of the subventricular zone surrounding the anterior tip of the lateral ventricle, referred to as the SVZa, to the middle of the olfactory bulb.

The progenitor cells of the embryonic telencephalon and the neonatal anterior subventricular zone differentially regulate their cell cycle.

For the last 10 years our laboratory has been studying the proliferation, migration and differentiation of neuronal progenitor cells located in the anterior part of the postnatal forebrain subventricular zone (SVZa). SVZa-derived cells possess a number of proliferative characteristics that distinguish them from the other progenitor cells in the central nervous system. This review summarizes our recent findings, in which we compared the pattern of cell cycle inhibitory proteins expressed by the neonatal SVZa to that of telencephalic ventricular zone cells.

Disruption of thermal perception in a multiple sclerosis patient with central pain.

Objective: To investigate integrative thermal perception in a patient with multiple sclerosis.

Design: Quantitative thermosensory testing was used to evaluate pain and other sensations produced by heat, cold, and the thermal grill pain illusion.

Patient: The authors report on a 43-year-old patient with central pain manifest most strongly in her left arm and hand, contralateral to an upper cervical spinothalamic lesion due to multiple sclerosis.