| 1. |
- Gunhaga, Lena, et al.
(författare)
-
Specification of dorsal telencephalic character by sequential Wnt and FGF signaling.
- 2003
-
Ingår i: Nature Neuroscience. - : Springer Science and Business Media LLC. - 1097-6256 .- 1546-1726. ; 6:7, s. 701-707
-
Tidskriftsartikel (refereegranskat)abstract
- Dorsoventral patterning of the telencephalon is established early in forebrain development and underlies many of the regional subdivisions that are critical to the later organization of neural circuits in the cerebral cortex and basal ganglia. Sonic hedgehog (Shh) is involved in the generation of the ventral-most telencephalic cells, but the identity of the extrinsic signal(s) that induce dorsal character in telencephalic cells is not known. Here we show in chick embryos that sequential Wnt and fibroblast growth factor (FGF) signaling specifies cells of dorsal telencephalic character.
|
|
| 2. |
- Marklund, Matthew, et al.
(författare)
-
Retinoic acid signalling specifies intermediate character in the developing telencephalon.
- 2004
-
Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 131:17, s. 4323-4332
-
Tidskriftsartikel (refereegranskat)abstract
- The organisation of the telencephalon into its major structures depends on its early regionalisation along the dorsoventral axis. Previous studies have provided evidence that sonic hedgehog (SHH) is required for the generation of telencephalic cells of ventral character, and that sequential WNT and fibroblast growth factor (FGF) signalling specifies cells of dorsal telencephalic character. However, the signalling mechanisms that specify telencephalic cells of an intermediate character remain to be defined. We provide evidence here that retinoic acid has a crucial role in specifying telencephalic progenitor cells of intermediate character.
|
|
| 3. |
- Nordström, Ulrika, 1971-, et al.
(författare)
-
An early role for WNT signaling in specifying neural patterns of Cdx and Hox gene expression and motor neuron subtype identity
- 2006
-
Ingår i: PLoS biology. - : Public library of science. - 1544-9173 .- 1545-7885. ; 4:8, s. 1438-1452
-
Tidskriftsartikel (refereegranskat)abstract
- The link between extrinsic signaling, progenitor cell specification and neuronal subtype identity is central to the developmental organization of the vertebrate central nervous system. In the hindbrain and spinal cord, distinctions in the rostrocaudal identity of progenitor cells are associated with the generation of different motor neuron subtypes. Two fundamental classes of motor neurons, those with dorsal (dMN) and ventral (vMN) exit points, are generated over largely non-overlapping rostrocaudal domains of the caudal neural tube. Cdx and Hox genes are important determinants of the rostrocaudal identity of neural progenitor cells, but the link between early patterning signals, neural Cdx and Hox gene expression, and the generation of dMN and vMN subtypes, is unclear. Using an in vitro assay of neural differentiation, we provide evidence that an early Wnt-based program is required to interact with a later retinoic acid- and fibroblast growth factor–mediated mechanism to generate a pattern of Cdx and Hox profiles characteristic of hindbrain and spinal cord progenitor cells that prefigure the generation of vMNs and dMNs.
|
|
| 4. |
|
|
| 5. |
- Azim, Eiman, et al.
(författare)
-
Skilled reaching relies on a V2a propriospinal internal copy circuit
- 2014
-
Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 508:7496, s. 357-363
-
Tidskriftsartikel (refereegranskat)abstract
- The precision of skilled forelimb movement has long been presumed to rely on rapid feedback corrections triggered by internally directed copies of outgoing motor commands, but the functional relevance of inferred internal copy circuits has remained unclear. One class of spinal interneurons implicated in the control of mammalian forelimb movement, cervical propriospinal neurons (PNs), has the potential to convey an internal copy of premotor signals through dual innervation of forelimb-innervating motor neurons and precerebellar neurons of the lateral reticular nucleus. Here we examine whether the PN internal copy pathway functions in the control of goal-directed reaching. In mice, PNs include a genetically accessible subpopulation of cervical V2a interneurons, and their targeted ablation perturbs reaching while leaving intact other elements of forelimb movement. Moreover, optogenetic activation of the PN internal copy branch recruits a rapid cerebellar feedback loop that modulates forelimb motor neuron activity and severely disrupts reaching kinematics. Our findings implicate V2a PNs as the focus of an internal copy pathway assigned to the rapid updating of motor output during reaching behaviour.
|
|
| 6. |
- Gunhaga, Lena, et al.
(författare)
-
Sonic hedgehog signaling at gastrula stages specifies ventral telencephalic cells in the chick embryo
- 2000
-
Ingår i: Development. - 0950-1991 .- 1477-9129. ; 127:15, s. 3283-3293
-
Tidskriftsartikel (refereegranskat)abstract
- A secreted signaling factor, Sonic hedgehog (Shh), has a crucial role in the generation of ventral cell types along the entire rostrocaudal axis of the neural tube. At caudal levels of the neuraxis, Shh is secreted by the notochord and floor plate during the period that ventral cell fates are specified. At anterior prosencephalic levels that give rise to the telencephalon, however, neither the prechordal mesoderm nor the ventral neural tube expresses Shh at the time that the overt ventral character of the telencephalon becomes evident. Thus, the precise role and timing of Shh signaling relevant to the specification of ventral telencephalic identity remains unclear. By analysing neural cell differentiation in chick neural plate explants we provide evidence that neural cells acquire molecular properties characteristic of the ventral telencephalon in response to Shh signals derived from the anterior primitive streak/Hensen's node region at gastrula stages. Exposure of prospective anterior prosencephalic cells to Shh at this early stage is sufficient to initiate a temporal program of differentiation that parallels that of neurons generated normally in the medial ganglionic eminence subdivision of the ventral telencephalon.
|
|
