Fig. 1. The basal telencephalon contains a repulsive activity for tangentially
migrating cells. (A) Schematic of the slice transplantation paradigm used to
analyze the migration of MGEGFP-derived cells in the absence of
cortex. (B,C) Migration of MGEGFP-derived cells (asterisk) after 48
hours in culture, labeled with GFP (B), and schematic representation of the
routes followed by the MGEGFP-derived cells (C). Arrowheads point
to cells in the pallial/subpallial boundary, dorsal to the striatum. (D)
Schematic of the slice transplantation paradigm used to analyze the migratory
behavior of MGEGFP-derived cells transplanted into dorsal
(striatal; position 1), intermediate (pallidal; position 2) or ventral
(preoptic; position 3) regions within the subpallium. (E,F) Migration of
MGEGFP-derived cells after 48 hours in culture, labeled with GFP.
Examples of migratory behavior of cells derived from transplants (asterisks)
into intermediate (E) or ventral (F) regions the subpallium. Arrowheads point
to cells migrating from the transplants. Note the limited number of cells
migrating from the transplant in position 3. (G) Schematic of the slice
transplantation paradigm used to analyze the behavior of
MGEGFP-derived cells forced to migrate towards the preoptic area.
(H) Migration of MGEGFP-derived cells (asterisk) after 48 hours in
culture, labeled with GFP. Note that very few cells migrate into the MGE
mantle (arrowhead) and virtually none into the POa. (I) Analysis of the number
of cells that migrated in to the mantle of the LGE, MGE or POa [which contains
the ventral midline (m)] in the experiments described in G. Total number of
cells (n=25): 5240 (LGE), 711 (MGE), 123 (POa). Histograms show
averages±s.d. Asterisks denote significant differences in migration
between the LGE and MGE (*) and between the MGE and POa (**).
P<0.001 in both cases. LGE, lateral ganglionic eminence; m,
ventral midline; MGE, medial ganglionic eminence; NCx, neocortex; PCx,
piriform cortex; POa: preoptic area; Str, striatum. Scale bars: 300 µm.