RT Journal Article SR Electronic T1 Tissue dynamics of the forebrain neural plate JF bioRxiv FD Cold Spring Harbor Laboratory SP 016303 DO 10.1101/016303 A1 Stephen Young A1 Joel N. Jennings A1 Guy B. Blanchard A1 Alexandre J. Kabla A1 Richard J. Adams YR 2015 UL http://biorxiv.org/content/early/2015/03/09/016303.abstract AB The forebrain has the most complex shape and structure of the vertebrate brain regions and the mechanisms of its formation remain obscure. Convergence and extension movements are characteristic of the posterior (spinal cord and hindbrain) neural plate (pNP) while tissue deformations and underlying cellular dynamics during the early shaping of the forebrain neural plate (fNP) are undefined. Here, we apply live imaging, automated cell tracking and computational analysis to quantitatively map cell behaviour in the zebrafish fNP. We demonstrate a novel mechanism in which planar cell rearrangements, with a passive signature, are orthogonal to those in the pNP, and cell divisions lacking planar-polarity facilitate thickening from two to three layers. We develop a mechanical model of the fNP in which polarised cell behaviour arises from interactions with dissimilar bordering tissues rather than from intrinsically polarised cells. The model unifies in vivo observations and provides a mechanistic understanding of fNP morphogenesis.