Tempting Fate and Commitment in the Developing Forebrain

Abstract

cells which integrated into the striatum were labeled for both M6 and [ 3 H]thymidine. The three populations of Department of Physical Therapy Temple University cells grafted by Campbell et al. integrated into a wide variety of host locations, including the striatum, septum, Philadelphia, Pennsylvania 19140 diencephalon, and, to a lesser extent, cortex. There were distinct patterns of integration for each precursor type. For example, their extensive analysis revealed that a Transplantation is a time-honored method that has been larger proportion of LGE cells than of MGE cells incorpoused for over a century by experimental biologists to rate into striatum. This suggests that at least a portion examine mechanisms involved in the formation of reof the mitotically active LGE neurons were regionally gional tissue patterns. This technique has been applied specified at the time of transplantation. The cells that recently to the mammalian forebrain to explore the exintegrate into the striatum express phenotypes approtent to which regionalization of this structure is regulated priate for their site of integration, such as striatal neuroby intrinsic versus extrinsic mechanisms. While a growchemical markers and projections. ing body of studies highlights compelling evidence for Campbell et al. also examined the exact nature of the role of extrinsic cues in driving phenotypic committhe cell-cell interactions occurring during migration. The ment of forebrain precursors, the studies reported in a mouse-rat graft-host chimeras show an association of recent issue of Neuron (Brü stle et al., 1995; Campbell dispersed mouse neurons with mouse glial cells, as did et al., 1995) have some remarkable findings. They illuschimeric striatal cells in grafting studies by Deacon et trate the extensive multipotentiality of both striatal and al. (1994). The neuronal and glial daughter cells of the cortical precursors when integrated into a wide variety mouse progenitors appear to differentiate in close conof forebrain regions. Striatal precursors placed into a tact with each other in many of the integrative sites. cortical environment display morphological and neuro-One possible explanation for this finding is that the glial chemical attributes of the host region, as do cortical cells are used at earlier stages for radial glial guidance precursors after integration into striatum. Furthermore, as the neurons move to their final laminar or nuclear the movement of the injected cells throughout the entire group locations. The use of the chimeric grafting techventricular system gives them access to ventricular zone nique, in combination with mouse antibodies, creates regions beyond the forebrain. Grafted chimeric cells can the potential for more precise examination of the in vivo be found integrating into areas as distant as mesencephalon, although further characterization is needed interactions of neurons and glia during migration. to examine the full extent of this integration. This grafting Brü stle et al. (1995), in the same issue of Neuron, ...

Differential effects of spinal cord gray and white matter on process outgrowth from grafted human NTERA2 neurons (NT2N, hNT)

“…Specifically, we found no evidence for phenotypic change in grafted NT2N neurons located in distinct spinal cord locations, except for differences in the outgrowth patterns of their processes. This is consistent with findings from embryonic cell transplantation studies (Tonder et al, 1988(Tonder et al, , 1990Wictorin et al, 1990;Fujii, 1991Fujii, , 1994Stromberg et al, 1992;Davies et al, 1993Davies et al, , 1994Li and Raisman, 1993;Barbe, 1996) in which precursor cells isolated from phenotypically different embryonic brain regions showed a multipotentiality that postmitotic neurons do not.…”

Pull-Push Neuromodulation of LTP and LTD Enables Bidirectional Experience-Induced Synaptic Scaling in Visual Cortex

“…The WM-IV inputs express pairing-induced NMDAR-dependent LTP/LTD (Figure 6A) for a brief postnatal critical period (Crair and Malenka, 1995; Dudek and Friedlander, 1996; Jiang et al, 2007). In slices from young individuals (P14-P15) isoproterenol selectively blocked LTD (F (3,14) = 14.79, p = 0.0003.…”

Transplanted multipotential neural precursor cells migrate into the inflamed white matter in response to experimental autoimmune encephalomyelitis

“…Transplanted multipotential stem cells migrate and integrate in the embryonic and newborn rodent CNS to adopt cellular identity according to local and temporal cues (Brustle et al, 1995(Brustle et al, , 1998Barbe, 1996). While the developing CNS is permissive for migration and integration of transplanted cells (Brustle et al, 1998;Flax et al, 1998), the normal adult brain does not permit large distance migration and does not support trans- planted neural cell survival (O'Leary and Blakemore, 1997).…”